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  Volkswagen Fixes.

Repacking Front Wheel Bearings

This procedure is based on the Haynes Manual, with notes from John Muir and Rob Boardman.
NOTE: The front wheel bearings should be serviced every 30,000 miles and/or when the brake linings are changed. Additionally, the bearings should be checked whenever the front of the vehicle is raised for any reason.
1. Raise the vehicle and support it securely on jackstands. Spin each wheel and check for noise, rolling resistance and freeplay. The wheels should turn freely without binding.
2. Grasp the top of each tire with one hand and the bottom with thej other. Move the wheel in-and-out on the spindle. If there's any noticeable movement, the bearings should be checked and then repacked with greases or replaced if necessary.
3. Remove the wheel.
4. On the driver's side, remove the clip from the end of the speedometer cable. On both sides, pry the dust cap off the hub.
5. Loosen the spindle nut lockbolt with a 6mm Allen wrench.
6. Remove the spindle nut and washer from the end of the spindle.
NOTE: The left side spindle has left hand threads.
7. Pull the hub assembly out slightly, then push it back into its original position. This should force the outer bearing off the spindle enough so it can be removed.
8. Pull the hub assembly off the spindle.
9. Use a screwdriver to pry the seal out of the rear of the hub. As this is done, note how the seal is installed.
10. Remove the inner wheel bearing from the hub.
11. Use solvent to remove all traces of the old grease from the bearings, hub and spindle. A small brush may prove helpful; however, make sure no bristles from the brush embed themselves inside the bearing rollers. Allow the parts to air dry.

12. Carefully inspect the bearings for cracks, heat discoloration, worn rollers, etc. Check both the inner and outer bearing races inside the hub for wear and damage. If the bearing races are defective, the hubs should be taken to a machine shop with the facilities to remove the old races and press new ones in. Note that the bearings and races come as matched sets and old bearings should never be installed on new races.
13. It is possible to install the new outer race yourself. Clean the wheel hub thoroughly. Hold the whole bearing up to the hub to make sure you know how it goes, with the heavy part in, then get the outer race started in the hole evenly all around. Use two hammers, one on the race and one to tap it with. Tap this race into the hub until it is inside the hub, then tap it in with a dull chisel until the race is seated on the shoulder of the hub. You can tell by the solid sound when it's seated. Now proceed to packing the bearings.
14. Repack both the inner and outer bearings with high-temperature front wheel bearing grease.
NOTE: Make sure the bearings are absolutely clean and dry. If they still have solvent on them (if you're replacing them, not putting new ones in), you cannot pack them until they have dried completely so put them in the sun and wait.
15. With the bearing in the palm of your hand, work the grease completely into the rollers, forcing it between the rollers, cone and cage from the back side.
16. Apply a thin coat of grease to the spindle at the outer bearing seat, inner bearing seat, shoulder and seal seat.
17. Put a small quantity of grease inboard of each bearing race inside the hub. Using your finger, form a dam at these points to provide extra grease availability and to keep thinned grease from flowing out of the bearing.

John Muir says to pack the hub full of grease. It will take about 50 grams of wheel bearing grease, a small handful. Start jambing the wheel bearing grease into the outboard end of the drum hub. Covering the inboard hole in the hub with your hand, fill the whole hub completely. Push the grease in really well, think of the 30,000 miles and smile.
Note from Rob Boardman: The bearings are not sealed themselves, so the hub needs to be packed with grease. This supplies a very large quantity of grease to the bearings, and so they last a long time. If the grease is renewed about every 30,000 miles (the grease seal too) the bearings will last forever.
If this process is done right, you'll probably find that the NEXT time you do it - there will be a small ridge of grease around the inside of the end (bearing) cap - close to the bearing. This means that the hub was nice and full, as when it got warm and expanded, a little was pushed out past the outer bearing and the spinning wheel stuck it to the inside of the bearing cap.
18. Place the grease-packed inner bearing into the rear of the hub and put a little more grease outboard of the bearing.
19. Place a new seal over the inner bearing and tap the seal evenly into place with a hammer and block of wood until it's flush with the hub.

The grease seal is rubber coated, and has a spiral spring around a groove in the seal. This spring keeps the inner sealing lip in contact with the axle as the wheel and seal rotate. This spring must face the inside of the bearing, so you only see the back of the seal when you install it. place the drum on a clean flat surface - smear a thin coat of grease on the seal where is will slide into the drum, place it on the drum and place a piece of smooth flat wood over the back of the seal. Now tap the wood with a mallet or hammer, gently working around the perimeter of the seal so it goes in a little at a time. It doesn't take a lot of force, but must be done evenly around the perimeter of the seal so it doesn't end up distorted.

20. Carefully place the hub assembly onto the spindle.
Note from John Muir: Wipe your greasy hands clean again, grab the hub and push it onto the axle. Help is nice at this point as you are trying to put the wheel on the axle while keeping grease in the hub with your third and fourth hands. As soon as the axle appear out the hub, pick up the outboard bearing and push it on, as it helps to hold the grease in. Don't be so enthusiastic about shoving grease back that you push it out the back hole. Just use all that it will hold.
Note from Rob Boardman: Any grease which get pushed out as the axle comes through is easy to push back in by running a finger round and round the axle.
21. Push the grease-packed outer bearing into position.
22. When the axle is out as far as it will come, tap the outboard bearing into its race and the hammer and dull chisel. Lift the wheel straight up with your foot so you can tap the bearing in. Clean up around the place with a little rag or rags, then go to the next step and adjust the bearings.

Note from Rob: The race has been fitted previously of course, so this just means inserting the bearing cage over the axle.
23. Install the washer and spindle nut. Tighten the nut only until all freeplay is gone.
Note from Rob: Nice and snug - as I've mentioned before. You should feel the drum start to bind. Keep turning the wheel/drum as you do this to help the bearing seat all the way in.)
24. Spin the hub in a forward direction to seat the bearings and remove any grease or burrs which could cause excessive bearing play later.
25. Check to see that the tightness of the spindle nut is still the same.
26. Tighten the nut by hand until all looseness and freeplay are gone. Now tighten the nut with a wrench approximately an addition 1/4 turn to create a very slight preload, than back it off about 1/8 turn. The acceptable amount of endplay is 0.001 to 0.003 inch.</LI<< P>
Note from Rob: I haven't done it exactly this way - just tightened it up till it started to bind, loosened it until the binding was free, then HAND (or a very light hand on a wrench) tightened it until it was just touching against the washer, then grab the upper and lower edges of the drum and push-pull to check for any play (look closely at the grease around the small bearing/washer/nut to see if it "bulges" as you push-pull). Re-do the tightening sequence if necessary. If it's loose the wheel will wobble - even if you can't feel it - and wear the bearings out, and if it's too tight, there will be insufficient grease between each roller and the race, so the bearing will run hot.
27. Tighten the spindle nut lock bolt with an Allen wrench to hold the spindle nut in place.
Note from John Muir: Put the washer on the axle, then the ... nut (left axle has left-hand threads).


From Rob: Good point that one. Designed so that if the allen key is not tight enough, the rolling wheel/drum will tend to do the nut up, rather than loosen it.
28. Use the crescent wrench to run this nut up pretty tight (7 ft-lb) while you hand turn the drum. This turning will take the slack out of the bearings. Now loosen the nut with the crescent a little at a time until you can just move the washer under the nut with the big screwdriver. Tighten it again, then loosen it until you can just move the washer. When that washer first moves upon prying it, this is the point that gives the wheen about .001" of end play.
29. Install the dust cap on the passenger's side, tapping it into place with a rubber mallet.
30. On the driver's side, reach behind the spindle and push the speedometer cable through the dust cap. Then install the dust cap and reinstall the clip to hold the speedometer cable in place.
31. Make sure that the studs in the brake drum are tight and secured with Loktite. Install the wheel on the studs in the hub and tighten the lug nuts.
32. Grasp the top and botom of the tire and check the bearings in the manner described earlier.
33. Lower the vehicle.
 


Remove/Install Instrument Cluster/Speedometer Cable

NOTE: For this procedure, "front" will mean the side of the instrument cluster from which the driver views the gauges; "back" will mean the side of the instrument cluster to which the speedometer cable and the various wires are attached. This use of "front" and "back" is opposite that normally used in discussing VWs, where "front" means the front of the car and "back" means the back of the car.
Instrument Cluster Removal:
1. Detach the cable from the negative battery terminal.
2. Remove the instrument cluster by carefully prying it away from the dash with your fingers (if you use a screwdriver, be very careful not to scratch the dash or the bezel around the instrument cluster.
NOTE: The instrument cluster is just pressed into the dash and held in place by a ribbed rubber boot that fits around it.
3. Disconnect the speedometer cable from the speedometer by unscrewing the threaded fitting that attaches it to the back of the instrument cluster. This fitting should only be finger tight.
4. If you need to take the instrument cluster completely out of the car draw and diagram of the back side of the instrument cluster and clearly label all of the wires (there are a total of twelve connection points). It is also a good idea to note all of the wire colors on your diagram just to make sure.
Speedometer Cable Removal:
1. Firmly set the parking brake, block the rear wheels, raise the front of the car and set it firmly on jack stands.

2. Remove the circlip which secures the end of the cable to the wheel bearing dust cap.
3. Working from the back side of the wheel, pull the cable out of the steering knuckle.
4. Pull the speedometer completely out through the hole in the dash.
NOTE: It will help to have an assistant under the car as you slowly pull the cable out so he can note the routing. Getting the new cable back in can be tricky.
Speedometer Cable Installation:
1. Pull the cable right out of it's sheath, wipe it clean with a rag, and rub grease down it's length with your fingers. Reinsert the cable in the sheath.
NOTE: If you are just lubricating a cable that you plan to reuse, grease it carefully, as you may find a 'sprung' wire or two, and wire punctures in the skin HURT. This will also tell you if it needs replacing again :-) The cable usually breaks near the wheel end, as this bit gets flexed in all directions and the wheel bounces and steers.
2. It's a good idea to install a new rubber sleeve in the steering knuckle to keep water out. If water gets into the knuckle, it can damage the bearings and allow the cable to freeze--and stick--in the winter.
3. Working with one person in the car and one person under the car, route the new cable from the hole in the dash through the hole in the firewall (there should be a grommet in this hole) and on down to the back side of the steering knuckle, following the same route that the old cable took.

NOTE: Route the cable to eliminate sharp bends (no radius less than six inches). Make sure it isn't kinked or pulled too tight anywhere in the turning radius of the front wheel. Be careful not to unseat the grommet when threading the new cable through.
4. Insert the wheel-end of the cable into the steering knuckle (from the back side). You will probably have to remove the dust cover to get the end of the cable properly aligned in the square hole. Install a new circlip at the end of the cable.

NOTE: It is actually the dust cap which turns the cable and thus drives the speedometer and odometer. Make sure the end of the cable is seated securely in the dust cap.
5. Screw the threaded fitting on the dashboard end of the speedometer to the back of the instrument cluster.
Instrument Cluster Installation:
1. Carefully reattach all of the wires (12) to the back of the instrument cluster, making doubly sure that each attaches at the correct point.
2. Orient the cluster properly and press it back into the hole in the dash.
 

Types of Ignition –

Introduction -

We have now tracked the fuel/air mixture from the carburetor, through the intake manifold, and into the cylinders by way of the intake valve. In the cylinders the fuel/air mixture is ignited by the spark plug, and the action within the engine begins. The ignition system is designed to get spark to the cylinders to burn the fuel to make the power to turn the engine, the transmission, and the differential and, finally, the wheels.

Look to a little left of the center of the engine and find a brown or black round plastic thing with five heavy wires sticking out of it. That's the distributor cap.

By the way, Front means the Front of the car and in the United States the "driver's side" is the left side. In England, Australia, etc. the "driver's side" is the right side.

Under the distributor cap is the distributor and inside the distributor are the rotor, the points and sometimes the condenser, but usually the condenser, which is a small cylinder, is attached to the outside of the distributor. The function of the condenser is to smooth and control the low voltage spark and keep the points from burning and pitting too rapidly.

There may be a bright metal biscuit, about 3" in diameter, on the side of the distributor with one or two metal or rubber hoses leading out of it; this is the vacuum advance. If you don't have this biscuit, your distributor is a centrifugal advance type.

When the ignition key is turned on, electrical current goes from the battery to the ignition coil, usually mounted on fan housing. Inside the coil are thousands of turns of wire, which increases the voltage to something like ten thousand volts, which is now available at the center large outlet from the coil and connects to the center large connection at the distributor cap. It takes a lot of voltage to make a spark jump across the spark plug gap, and this is the way we get it.

The coil also has two side connections where smaller wires are either bolted or push-on connected. On one side is a thin wire that goes from the coil to the distributor (usually green); on the other side are a wire that brings juice from the ignition switch, a wire that goes to the automatic choke, a wire to the carburetor cut-off jet, and a wire to the back-up lights.

The function of the distributor is to time the spark impulses to the spark plugs so that they fire at the proper time so as to burn the compressed fuel/air mixture, drive the pistons, and provide power to the car. The distributor shaft is driven round and round by a gear on the crankshaft. As it goes round and round inside the distributor it opens and closes a set of ignition points.

The distributor shaft inside the distributor is almost square, and at each point of the square it opens the ignition points. In between the high places the points close. When the points are closed, the twelve volt current (or six volt in older VWs) from the key is built up to high voltage (think of it as pressure) in the coil so that when the points open there is plenty of voltage to make the spark jump from the rotor to the pin inside the distributor cap and thus through the heavy wires to the spark plugs, providing a hot spark to burn the compressed fuel/air mixture in the cylinders.

So when the points open there are two sparks that jump in the distributor cap -- one 12-volt (or 6-volt) spark in the bottom between the points, and one high-voltage spark in the distributor cap.

Back to the heavy wires coming out of the distributor cap. These are the spark plug wires which carry high voltage current from the distributor to the spark plugs, which are down on either side of the engine. Two go to the right to cylinders 1 (front) and 2 (rear), and the other two go to the right to cylinders 3 (front) and 4 (rear). On the spark plug end of each heavy wire is a plastic spark plug connector which screws onto the end of the wire.

NOTE: You must never pull on the spark plug wire -- always pull on the plastic connector to get the connector off of the spark plug -- they just push on.

Around the plastic spark plug connector is a rubber seal which keeps air from coming out of the shrouding (all that tin around the engine). These seals must always be in good condition and pushed into place so as to seal the air in; otherwise cooling air from the fan will leak out and the engine will get hot. If they are beat, make a note to get new ones and put them on.
To summarize: The high-voltage current passes from the center of the coil through the center of the distributor cap to the rotor. From there the current jumps to the post in the cap and through the proper wire to the proper spark plug to ignite the compressed fuel/air mixture in the proper cylinder at just the right time -- and this happens more than 7000 times a minute!


*How to Keep Your Volkswagen Alive --
A Manual of Step-by-Step Procedures
for the Compleat Idiot,
1976 Edition, pages 14 and 37.
 

Types of Ignition Systems

There are four different ignition systems you can use on a VW:
1. The stock points/condensor system. Works OK, but the voltage at the plugs gradually drops as the rpm increases (this happens with all points/condensor systems) and the points will also start to "float" at very high rpm. The plugs get about 18,000 volts. The points wear fast because they have to switch about 5 amps, and so they spark. The condensor reduces the sparking but it still happens so the points wear out (burn). The spark also slows down the switching process, so the coil gets a "soft" switch and the resulting plug voltage is a little less than it could be. (The coil produces the high voltage to the plugs when the points open and the magnetic field inside the coil collapses. The faster you can cut the power to the coil the faster that field collapses so the better the plug voltage).
2. The Pertronix/compufire points replacement modules. These replace the points with a hall-effect sensor or (in some earlier models) an optical sensor. They electronically switch the power to the normal coil, so the coil is still working at 12v (but the elecronic switching is faster than the sparking points so coil performance is a little better). The plugs get about the same 18-20,000 volts. These points replacement units don't wear so your timing stays very steady and doesn't need adjusting much.

3. Transistor assisted ignition. These use a very small current through the points to switch a power transistor on and off (imagine the power transistor as an electronic relay - using a small current to switch a bigger current) and the power transistor supplies a normal 12v to the coil. But like the Pertronix it provides faster switching than sparking points can, so coil performance is a little better than stock - still in the 18-20,000 volts range to the plugs though. The points last a long time as they don't spark any more - only a tiny trigger current flows through them. These systems are not very common these days, but will work well, and are easy to build. You could consider these sytems as a cheap alternative (but roughly equivalent) to the Pertronix/Compufire.

4. CDI - Capacitance Discharge Ignition. This can be triggered by 1 or 2 above, but is not used in conjunction with 3 at all. (Consider it as a BOOSTED #3). The CDI system has a couple of very large capacitors continously charging from a high frequency circuit using a "toroid" (donut shaped) transformer inside the unit (the high frequency produces the characteristic whine like a camera flash charging up) and when the points or the Pertronix triggers it, the capacitors dump about 400v through the coil, so you get about 40,000 volts out of it for the plugs, rather than the normal 18-20,000v. This provides a thinner but much hotter spark which will light a weak or rich mixture, so you get easier starting, and you also get slightly better economy, and your plugs last longer. And of course - if you use it with the normal points, the points will last a long time because they are only providing a small trigger current - the capacitors are providing the main pulse to the coil. You can open the plug gap a little with a CDI - for a longer spark. Up to about 45thou, but if you set it at 35thou you can forget the plugs for many thousands of miles - the electrodes with still burn away slowly, but won't go "over gapped" because you started with a modest increase. One useful feature of POINTs fired CDIs is that they can be used to upgrade the ignition on early VW engines and still retain the retarded No3 ignition which is needed for the non-doghouse engines.
MSD is usually a variation of the CDI - providing a multi spark rather than a single spark.
There are also magnetos which will fit the VW engine - these are self contained ignition systems - no battery is needed, and are sometimes used in VW aircraft engines.


 

Wisdom of Bob Hoover

 

Dave wrote to Bob Hoover, a well-known VW guru in Southern California -
Bob, I need some input regarding the single vs double vacuum distributor... It's not real clear to me which of the two distributors (single/double vacuum) is the right one to use with my 34 PICT/3 carburetor.
I called the man at a local VW repair shop; the guy called the warehouse and talked to them about the double vacuum distributor. They want over $300 for it new! They asked him why he wanted to know; he told them what I had said (passing along your advice) about the 009 and the 34 PICT being incompatible. They said that the double vacuum distributor was made for use in California ONLY!
This shop has a rebuilt single vacuum distributor for about $90.
So once again I'm in a quandary. Do I believe a source that has proven itself unreliable and buy the cheaper single vacuum model and hope for the best? (I'm inclined to, as I really don't want to have to shell out over $300 for a new distributor!)
Do you have any cogent words of wisdom? I'm getting desperate with this lousy hesitation problem; I want to do the right thing, hopefully without breaking the bank!
Bob Hoover responded -
1. The 34PICT's will work with ANY vacuum-advance distributor.
2. The double-canister distributors are used on engines having a very low static-timing point to insure complete combustion at idle speeds. (The alternative would have been using a different cam.)
 

3. The VW cam, valves, intake & exhaust volume dictate a particular advance-point for proper operation, which is up around 30 degrees BEFORE TDC and which generally is all-in by about 2500 rpm. Above that, the same factors serve to limit the engine's output, a very sophisticated form of rev-limiting.
4. A vacuum-advance distributor will NOT give you that much advance in a linear fashion.
Now look at what you've got: A dictated AFTER-TDC static-timing point on an engine whose optimum operating speed demands a firing point of about 30 degrees BEFORE-TDC... and inherent limitations in vacuum-advance distributors which prevent them from covering that range.
So you use a composite distributor, one having BOTH vacuum advance, which gives the required responsiveness, AND centrifugal advance, which gives you the desired range.
The retard side of the canister was added to insure a positive back-down of the firing point when the throttle was closed. Otherwise, the firing point would decay according to the speed of the engine (ie, under the control of the centrifugal-advance system). Even then, it was an interim solution until they could get the bugs out of the fuel injection system. (Mexican bugs are fuel injected. Very nice, reliable system. Illegal in Ami-Rica, of course.)
If you do not see the retard function, don't use it. On a dual chamber canister that means disconnecting the retard-signal line. (It will usually be the lowest pick-off point on the carb.) You need to seal the lines to prevent anything getting into the canister or being sucked into the manifold. And of course, re-time the thing.

If you have a single-canister distributor (or a dual-canister distributor with the retard side disabled), set your static timing at about 7.5 degrees BEFORE TDC and drive on. Most vacuum-advance distributors will give you about twenty degrees total advance. Check it with a timing light by revving the engine. Tweak accordingly but don't push it too far -- hot day, low-octane fuel, you?ll get detonation even though everything is set to spec. I fun about 28 degrees total advance.
(In earlier messages to you and Rob I've not mentioned the initial static timing point because I assumed the principle was understood with regard to emissions and the carb/distributor combo.)
If you don't have a good vacuum-advance distributor, go get one. Go to a junkyard and buy half a dozen of the things in beater condition. Remove the vacuum canisters. If you can't find a good vacuum canister, go buy one. (Replacements run about $25, new, Bosch, here in southern California.) Throw the distributors in a can of oil to soak over night, then dismantle them. Be careful to preserve the spacers and washers -- they're hard to find (I often buy a new -009 just to get the spacers!) Match the best fitting shaft-to-housing and reassemble the distributor using a proper number of shims and spacers to give minimum end-play. Go drive the thing.
If you want to make it last forever, or at least longer than the 70,000 or so it normally lasts, get rid of the points. Opening the points represents as asymmetric load on the distributor. Opening the points is the major cause for wear on the shaft and bushings. So get rid of them. Use a Pertronix unit. No load on the distributor shaft. Runs concentrically. Vastly reduces the wear-rate which is already pretty low because the distributor only turns at one-half engine speed. (Don?t use an optically triggered unit. The Pertronix is magnetic. The Hall effect sensor, amplifier and SCR are contained in the pick-up unit.)

Okay, so you're not a mechanic (you should be, if you want to own/operate an orphaned, antique vehicle). A new, vacuum advance distributor costs about $90. Roland Welhelmy bought one a couple of weeks ago from the Old VW Company in Escondido and sent a note about it to the Type 2 mailing list. (OVW = (760) 73-7587). Give them a call, see if they'll send you one. Ditto for the Pertronix unit, while you're at it. (It runs about $60.)
Regarding advance mechanisms: You can make a centrifugal system advance as far as you want and at whatever rate you want. Friction and loss of spring tension is the only problem. But with a vacuum-advance system, the thing is only linear across a fairly narrow range, although marvelously responsive within that range. Most cars use composite or combination systems -- a vacuum-advance to initiate acceleration and a mechanical-advance to continue that advance to whatever limits -- and at whatever rate -- the engineers decided upon.
But one thing you CAN'T do is stick a purely mechanical system into a VW and expect it to be responsive to the throttle. First, you must bring about a change in rpm, usually by feathering the throttle -- pumping a little more gas -- THEN the advance kicks in -- and will advance as far as you want it to, depending on what you've done to the bob-weights and springs. This is perfect for the dragstrip, where you jack it up to three grand before you even pop the clutch, and thereafter go flat-out thru only two gears, at most. The -009 is great for that. Otherwise it's a piece of crap.
Personally, I think you should be driving a Toyota. Early air-cooled Volkswagens require about ten times the annual preventative maintenance of a modern vehicle and it must be SKILLED maintenance. If you gotta pay someone to do it, you VW is going to cost you more than a luxury car. And if you don't do the maintenance, you're going to have a crappy ride. And if you try to do it yourself and screw things up. A Toyota seems like a good idea to me.
 


 

Notes on the Centrifugal vs Vacuum Controversy

Pro Centrifugal Advance -

John Muir* wrote -

Just what kind of distributor do you have? Volkswagen has used three main types through the years: mechanical (centrifugal) advance, semi-mechanical advance and vacuum advance. The first two types have been the same all the way, but the vacuum advance distributor has gone through several modifications and has been standard equipment on all models for many years. I hate them! They are another sop to American buyers who refuse to learn to shift a car with a little coordination. This is just a personal beef, so forgive me. I use a straight mechanical advance distributor, called the Porsche Type, which advances the distributor on rpm as the engine speeds up. Most VW race cars and beach buggies use the same. It gives a very good power curve on the VW engine.

The vacuum distributor advances the spark based on the vacuum in the carburetor (as opposed to rpm) and they will never make good since the principle is wrong. That, however, is what they give you with the car. I saw a demonstration 1969 accessory car on a VW showroom floor with a speed set-up on the engine, and guess what? Right. It has a mechanical advance distributor on it and at o only $30.00 extra, so when you get bread ahead, buy one for your jewel. You have to block up the hole (or holes) in the carburetor so it doesn't leak vacuum. Vacuum leaks burn valves, if you didn't know. Now that's out of my system.

*How to Keep Your Volkswagen Alive --
A Manual of Step-by-Step Procedures
for the Compleat Idiot, 1976 edition, page 90


Rob Boardman says -
The 009 does often cause acceleration flat spots, and these can usually be overcome by ensuring the accelerator pump is adjusted for it's maximum stroke, and you might need a richer main jet in the carby.
I have heard of a couple fixes for a 34PICT and 009. One from this newsgroup which is to pop rivet the hole in the throttle plate and the other is to go with a bigger idle jet.
Dave wrote to Rob -
Regarding the distributor: Have you been following the responses on the Newsgroup to the guy who put in a 009 and thought it was wonderful? The responses are running VERY heavily in favor of the vacuum advance dizzy. I think we did the right thing.
Rob responded -
Yes, I noticed this too. Since I found out what they were originally designed for (hard working 1200 busses, and they also appeared on some of the industrial engines, which work at more constant speeds), I've been telling the story to anyone who'd listen. My main argument is that since VW obviously ARE familiar with 009s, and didn't use them with any of the bigger engines, they obviously felt that the engines worked better with vacuum distributors. There were only ever two kinds of centrifugal-only, the 009 and the VW equivalent (which I think was a 050), but they tried lots of variations in the vacuum distributors, so the inference is that they found the 009 etc. unacceptable, but in their inimitable style, they fine tuned the vacuum distributors with the various engines.

Pro Vacuum Advance -
Rob wrote -
The 009s are a very common replacement distributor, but have serious limitations when used in road vehicles, since they are centrifugal only, and so they can't "load sense" like the vacuum distributor.
They are also a "one size fits all" distributor, which means that they are not "ideal" for any particular engine type. They do work quite well in applications where the VW engine is operating at high rpm and high power, for example, racing VW engines, or powering compressors and power generators.
And when rpm is high we need more advance, and when rpm is low we need less advance.
Fortunately, the vacuum distributor (and the combined centrifugal/advance of 74+ distributors) does a reasonable job of following these two conflicting needs. The vacuum port on solex carburettors is placed just UNDER the main venturi, close to where the throttle plate passes as it opens. So imagine the engine idling. The throttle plate is nearly closed, so there is a low airspeed through the main venturi - not much vacuum there or just under it (above the throttle plate). The vacuum port sees very little vacuum, and the idle advance setting prevails (7.5-10BTDC on most models).
Now open the throttle a little, so the edge of the throttle plate passes by the vacuum port. This creates a mini-venturi with very high air speed, which creates a lot of vacuum, so you get a shot of advance to help speed up the engine (this effect is entirely missing with the Bosch 009 distributor, which is what causes the "009 flat spot"). Since in a part-throttle condition you still have a high proportion of burned gases for a low flame speed, this high advance also meets the advance condition needed to deal with that too.

Now open the throttle right up. The throttle plate moves away from the vacuum port (no mini venturi) and so the MAIN venturi is providing the vacuum effect, but since the airspeed hasn't yet increased much yet (engine hasn't yet increased rpm), the vacuum signal is lower than part throttle, so the advance is reduced a little. Perfect for a fresher mixture (lower proportion of burned gases with an open throttle remember?). Now the engine rpm starts to catch up with the open throttle, so the airspeed through the main venturi increases, vacuum increases, and the advance increases progressively, which is just what you want for the increasing rpm, since the crankshaft is rotating in less time so you need more advance to get that fresh charge completely burned at the right moment.
So the vacuum distributors allow for high advance at high rpm/open throttle, where rpm is the dominant factor; and also allows high advance at part throttle/medium rpm, where the proportions of burnt/fresh mixture is the predominant consideration.
"Speedy" Jim wrote -
Sounds like somebody substituted the well-known Bosch ?009) distributor. This has centrifugal advance only. Some people swear by it. (Others swear at it!) Lacking vacuum advance, it is slower to respond to load changes or throttle opening and thus the hesitation. (Do check the pre-heat temp, though, as well.
My personal preference is for the stock (double vacuum) distributor, but they are hard to find in good condition and expensive to buy new. Swap meets are a good source. Be aware, though, that there were a dozen or more models, all look alike.
See The Wisdom of Bob Hooveron this subject.

Dave wrote, regarding installation of the vacuum advance distributor -
I turned the rotor to #1 and pulled the 009 distributor out. Then I set the points in the new one (double vacuum) and slipped it in place. It's interesting that #1 is on the left side; it was on the right on the 009. I attached the vacuum port on the silver canister to the port on the back (back) of the carburetor with rubber tubing. Then I attached the port on the bottom front (front) of the canister to the vacuum port on the left side of the carburetor--rubber tubing on the ends and a piece of copper tubing bent in the shape of a trap in the middle.
I static timed it to 5 degrees ATDC just to get in the ball park, and fired her up. The car started with no problem. I pulled it out of the garage onto the driveway and proceeded thru the detailed tuning -- dwell angle at 50 degrees, timing at 5 degrees ATDC with the timing light -- then to the idle. No dice. I tried to reduce it below 1200rpm -- wasn't having any. The engine died when I got it down to 1000. I'm absolutely clueless.
(Dave later discovered a severe air leak around the throttle shaft in the bottom of the carburetor into the intake manifold, which was making the fuel mixture very lean and requiring a high idle to keep the engine running. This discovery resolved Dave's nagging problems with hesitation and inability to properly set the idle.)
Then I took the car out for a test drive. It's considerably better, but not perfect. My wife said it seemed to "fweem" better to her, and it does. But it's still a little rocky. The guy at the VW shop claims that the problem is the 34 PICT carburetor (they put it on the engine when they rebuilt it!). He says I should go to either the 30 or 31 -- the car will never run right with the 34. The best combination (he claims) is the 009 dizzy and the 31 carburetor. I'm getting too much advice -- I don't know who to believe! Actually, yes I do. I lean heavily to your advice (Rob) and that of Bob Hoover, and I will continue down the vacuum advance dizzy path.


Dave wrote to Bob Hoover -
Thanks for the great "sermon" on vacuum vs centrifugal distributors. It finally tipped me over the edge--yesterday I bought and installed a rebuilt vacuum advance distributor, replacing the 009 that was causing our '73 SB to hesitate on acceleration. The guy that sold me the new dizzy said, "Be sure to keep the 009--you'll be putting it back on in a week!" I don't think so--the new dizzy has virtually eliminated the hesitation problem that has been plaguing us from day one. (There sure is a widely divided opinion on centrifugal vs vacuum advance distributors!)
Rob wrote -
Don't forget, with the 009 distributor you normally need to run a larger main jet, and sometimes a smaller air correction jet (I'm not sure how the progressives are actually set up). This helps make up for the lack of vacuum, and reduces any flat spots in acceleration, at the expense of higher fuel consumption.


 

The 009 Centrifugal-Advance Distributor --
History and Notes


Someone wrote -
Ever since I came into the VW scene (about 2 yrs) I've been hearing people going on and on and on for the 009. Where the heck did it come from? Was it a stock part for certain VW's? And what difference will it make on my 1969 1300sp engine. Oh yeah, and whats that "flat spot" all about?. Im VERY confused.
Rob responded -
VW built a lot of industrial engines (called type 122 for the 1200 and 124 for the 1600) as well as those built for the beetle itself.
Industrial engines powering generators, compressors and such are near enough to constant speed, so only a simple distributor was needed. So a centrifugal distributor was developed by VW, and later by Bosch. This type of distributor increases the amount of advance as the engine speed rises, but can not sense the throttle position (engine load). This is fine for engines operating at constant speeds, or at high power and high rpm (for VW racing engines for example, plus the previously mentioned industrial engines).
When the first Type 2 (Kombi etc) vehicles came out (1954 I think), they used the 1200 VW engine and needed reduction hubs so that the tiny engine could push a heavy vehicle (with a top speed of about 85kmh since the reduction hubs meant it was revving it's heart out!).
Because these engines in the Type 2 were working at high rpm and high throttle most of their life, the VW version of the centrifugal distributor was used on them too (but just try getting one off the line - they needed a lot of revs and clutch slip to avoid bogging down).

Most engines in road vehicles operate at various engine rpm and load conditions, which requires a lot of variation in the amount of advance needed for optimum engine performance and economy. Ideally, the amount of advance varries from about 7 degrees to about 42 degrees, depending on the engine model and it's intended use.
So most road vehicles use vacuum sensing, or a combination of vacuum and centrifugal, to get the best timing over a wide range of engine operations -- low throttle low rpm, low throttle high rpm, high throttle high rpm and every variation in between.
The early beetles used single vacuum distributors (SVSA). Then in 1971 they introduced the double advance technique -- using both rpm-related and vacuum-related advance. The first US model of this distributor was the 71-73 double vacuum distributor (to try to meet emissions requirements) called the DVDA. In other parts of the world a single-vacuum dual advance (SVDA) was used. From 1974 onwards the US also went to the SVDA. The SVDA distributor works like a high quality 009 with added vacuum advance.
These distributors are quite expensive to build in comparison with the Bosch 009 (the Bosch equivalent of the VW centrifugal distributor). So the cheap-to-build Bosch 009 became the "one size fits all" replacement distributor, since it IS so cheap, and it does work moderately well. But precisely because the 009 is a "one size fits all" distributor, it is NOT ideal for most engines, and it can cause problems for some engine/carby set-ups.

To accelerate an engine smoothly, you need both extra fuel and an extra advance. The accelerator pump provides the extra fuel and the vacuum distributors provide the additional advance needed. But a 009 cannot provide any advance until AFTER the engine rpm starts to increase (the advance starts happening at around 1200-1300 rpm) so, if the carby is set to run a little lean (LESS fuel), you get a hesitation or "flat spot," which usually means the driver has to blip the throttle a time or two to get the rpm up to the point where the 009 is starting to advance, then "feather" the throttle (and slip the clutch) so the rpm stays high, to avoid that flat spot.
The most common technique to overcome the 009 flat spot is to replace that "missing" advance with extra fuel - a larger main jet, max stroke on the accelerator pump, and in some cases filling in the air-bleed hole in the throttle butterfly. By running the engine richer than normal throughtout its operation, the flat spot is minimised.
The earlier Solex carburettors (28PCI, 28PICT and 30PICT/1 and /2) are set to run a little on the rich side - the VW engine actually likes around 13.8:1 air/fuel ratio, where the ideal is 14.5:1). So since these carbies are set to run rich anyway, the flat spot is often not noticable, or can be tuned out with minor adjustments.
But in 1970/71 the emissions problem was becoming recognised and VW changed the jetting on the 30PICT/3 (1970 US only) and the 34PICT/3, and /4 to run the carby leaner - closer to the ideal 14.5:1 air/fuel ratio (the California 34PICT/4 used especially lean jetting and a throttle positioner to ensure that the throttle closed slowly after you lifted your foot off the pedal).

So with this leaner running carby set-up, the 009 flat spot becomes a real issue.
You'll hear most complaints from folks who use the 34PICT/3, 34PICT/4 or the modern equivalent for the smaller carbs - the Brosol H30/31 (which is almost identical to the 1970 30PICT/3) - all of which normally come with lean jetting.
Another issue with the 009 is the limited maximum advance. The vacuum distributors can run up to about 40-42 degrees under the right conditions (light throttle and medium speeds for example) and this helps fuel economy. But if you maintained that much advance with a full throttle and low/medium rpm, the engine would ping/detonate, a problem which can destroy an engine if not corrected. The reason is rather technical, but is mainly related to the amount of residual exhaust gases which are left in the cylinder compared to the incoming charge. There is always SOME residual gas, since there's a head space above the cylinder. At part throttle there is a proportionally larger amount of burned gases in comparison to the fresh stuff (throttled fresh mixture but same head space of burned gasses). At full throttle there's a lower proportion of burned gases because you are letting in MORE fresh mixture for the fixed volume of head space. This "contamination" of the fresh mixture alters the flame speed (the time it takes for the fuel/air mixture to burn) so open-throttle needs less advance (burns faster) and part-throttle needs more advance (burns slower) at any particular rpm.

Incidentally, this is part of the reason why the low compression 1200s need more advance - usually 10BTDC compared to 7.5 BTDC for most 1500/1600s. Low compression means more head space (compared to the cylinder volume), and so there is more contamination of the fresh charge throughout the rpm range, and that means a little more advance is needed so all the fuel is burned just as the piston starts it's descent.
There is an rpm-related issue, too. As the engine rpm increases, the spark needs to occur sooner (more advance) to make sure the maximum pressure on the piston occurs just as it starts its descent.
The vacuum distributor senses throttle position, so if you floor the throttle at low-medium speeds, the distributor is able to "back off" the advance until the engine speed catches up with the new throttle position (slowly allowing the extra advance back in as the rpm/airflow rises). The 009 can't do this, so it HAS to be set to "worst case," which is between 28 and 32 degrees at 2500-2600 rpm (which is why we set the 009 at 3000rpm - to make sure that all the advance is present).
Since the 009 has been limited to 28-32 degrees compared to the vacuum distributor's 40-42, it's actually UNDER-ADVANCED for a lot of driving conditions, and this means worse fuel economy. And because you need to set the carby to run rich to reduce the flat spots, fuel economy suffers even more.
Because the 009 is built very cheaply, the total amount of advance varies from one to the next. This means that when setting the 009, it's important to set it at max rpm, not idle, since the max advance is much more important for most engine conditions. Always use as much of the 28-32 as the engine can take without pining/detonating, as this will reduce any flat spots just a little, and also help fuel economy just a little. If it still pings at 28 degrees, always use a higher octane fuel. NEVER use less than 28 degrees because it means the engine is seriously under-advanced at higher rpm and will run hotter than it needs to, and fuel economy will suffer as well.
In the heavier-bodied Kombi/Bus and Karmann Ghia vehicles, you might need to limit the max advance to the 28-30 degree range. These engines are less likely to tolerate the 32 degree maximum, as they are driven with more throttle to accelerate the heavier body.
Once you have determined the maximum advance which works well for your 009, you can then measure the idle advance (which will probably be between 5 and 10 BTDC but might be outside that range). If you want to, you can then use THAT setting for THAT 009 distributor to set it at idle or static.
So you can see that the 009 distributor is NOT ideal, but it will work. For best performance under all engine operating conditions, we recommend using a vacuum distributor.
Hope all that makes sense.
There are Tune-up Articles on our Web site which include info on both vacuum and 009 distributor settings.

Rob wrote -
My Bug is telling me that it needs a little TLC -- just a slight tendency to run rough at idle. I'll bet it's a "hill" growing on the points, a common problem with mine. I keep a "points file" (like a flat nail file) handy for just this purpose. If it goes off between oil changes (when it gets looked at each time), a few gentle rubs with the file by pushing them open when they are closed -- off the cam -- and letting the points spring hold the two sides of the points against the file. About two minutes and it's done. Emery paper works too -- but since the stuff is non metallic, anything left behind will act as an insulator, which occasionally causes it not to fire until you pull something else between the points and wipe them clean. The points file, being a metal file, doesn't have this problem.
The "hill" which grows between the points has the effect of reducing the advance -- sparking later -- and if left to get too bad it will cause it to "miss" the occasional spark altogether.
That is certainly one advantage of the electronic ignitions - no wear on the points, or eliminating the points altogether, so there is no wear on the rubbing block either.
 

Operation of the Vacuum Lines


Dave wrote to Rob regarding the vacuum lines on a dual vacuum distributor -
I've never understood completely which vacuum line went where. I think I've got the vacuum lines hooked up backwards! Let me make sure I have this straight:
• The MAIN vacuum line attaches to the port on the vacuum chamber at the rear (actually mine comes out of the side pointing toward the fuel pump, but that's okay) and goes to the vacuum port on the left side of the carby under the stepped cam. This is the line that is metal and has the dipsy-doodle fuel condensation trip in it.
• The RETARD vacuum line attaches to the port on the front (front) bottom of the vacuum chamber and goes to the port on the rear of the carburetor, just to the right of the throttle return spring.
~~~
Retard Line
Question -
Is there a way to determine whether the retard vacuum line is inoperative?
Rob responded -
Yes -- take the cap off the distributor and suck on each of the lines in turn. You should see the points plate move in opposite directions. The retard line will only retard a little of course, compared to the main vacuum's advance.
Question -
If the retard vacuum line is malfunctioning, what is the fix?

Rob responded -
First see if the hole in the carburetor is clear -- put the vacuum line back on it and blow from the dizzy end to see it you get air through. If it's good, the most likely cause is a broken/leaking vacuum chamber on the dizzy. The retard line only works (when it's working) at idle anyway, so it's less critical than the (working) advance line.
The main vacuum line gets quite a lot of vacuum with the engine running, and may cope with a small leak, but I think the retard vacuum probably operates at a lower pressure difference (engine idling anyway), so would be more susceptible. You can check for a leaky diaphragm by sucking on the main vacuum line, then block the line with your tongue and see if the points plate stays put. If it slowly moves back then you have a leak.
If you do end having to replace the vacuum chamber, they are pricey (here they cost more than a whole 009), and (on the single vacuum units like mine anyway) you have to check for a number on the vacuum operating arm inside the dizzy (the pushrod). This identifies the exact vacuum chamber for that distributor (there are several versions at least for the single vacuum units).
 

Advance Line

From Rob -
Try this... put the timing light on it and get is up to a steady speed where you see some advance but not all of it say 1500-2000. Now blip the throttle open and let it go so the revs don't change much but the load does. If the vacuum line is operating at all you should see the advance change momentarily then return to whatever it was. If the advance vacuum line is not working, the advance should stay reasonably steady -- only changing with the revs. If this is the case, the dizzy is definitely a dual advance (vac/centrifugal) operating like a 009 (centrifugal only), and this would explain the hesitation you are still getting. These dizzies are supposed to provide the best of both worlds for the VW if you can get it working right.
~~~
Overall Operation
Dave wrote -
We went out and conducted the test you suggested this evening. Here are the results:
1. Sucking on the main advance line alone products no movement in the points plate (however, the spark DOES advance with increasing RPMs, as we have shown with the timing light).
2. Sucking on the retard line alone moves the plate clockwise.
3. Sucking on both lines (advance first, then retard and holding suction on both) produces no discernible effect.
We have already established that this distributor is a combination centrifugal/vacuum advance model.
I hope these results mean something to you that you can then share with us so we can improve the around-town performance of this car.

Rob responded -
You have said that the retard line DOES work (that's the front line - nearest to the distributor body). So since the engine is off when you do it, then contrary to John's reply, it HAS to be retarding from neutral.
And there is only a tiny amount of suction in the advance line at idle, so how is the retard line supposed to be "only working to reduce the main advance". That doesn't make sense to me. Sure the two vacs work against each other as you open the throttle - the retard vac drops away because it works at the edge of the throttle plate which is now moving away (opening), and at the same time the airflow through the main carby venturi is increasing which increases the main vac, so the retard drops out and the main vac pulls in some advance.
Dave wrote -
So it is my understanding that the retard line works to pull in retard first, then the main vacuum takes over as you open the throttle.
Rob responded -
On my vacuum-only dizzy, the plate moves counterclockwise to produce advance (the vac arm pulls outwards). The retard line pushes the arm inwards and rotates the plate clockwise (same direction as the rotor moves). The RETARD pipe on the canister is the FRONT one - nearest the distributor body. The ADVANCE line is on the REAR (outer) side of the canister.
Another test to check it all out -

Try running the engine at 3000-3500 and check the timing. It should be AT LEAST 30 degrees or more (30 degrees if only the centrifugal is working - more if the vac advance is working too). If it's less than 30 degrees, disconnect both vac lines at the carby and plug them, then adjust the timing for 30 degrees at 3000rpm (this means you are setting it using just the centrifugal advance), then reconnect both vac lines.
Now drop the revs back to idle and look at the timing again. Is it 5ATDC or thereabouts? If so, the retard vac line is working OK. And if it is working, as you gently open the throttle with the timing light still on, the timing should change rapidly from 5ATDC to some positive figure as the retard line stops working.
But if its somewhere from 0 to 10BTDC at idle, my guess is that it's the RETARD line which is not working. I say 0-10 because I don't know exactly what the "neutral" plate position is on these dizzies.
This is just a test set-up, and I haven't tried it myself as I don't have the same distributor, but it might help determine which vac line is actually working and which isn't.
You'd need to re-time the engine properly after doing this test (5ATDC at idle with vac line properly connected.)
Dave asked, regarding disconnect of the vacuum hose(s) during timing -
The manuals don't clarify which end of the hose is to be disconnected from the distributor and plugged -- the point is to keep the carburetor from sucking air. Right?

Rob responded -
Precisely. The aim is two fold:
1. Stop the advance plate from moving so you can set the 7.5BTDC idle unaffected by any vacuum. Plugging the distributor end of the vac line is irrelevant at this point -- it's inoperative anyway.
2. Prevent the carby from sucking air through the vac line so it idles evenly whilst making the idle adjustment. So you pull the vac line off and plug the carby end. The carby creates the vacuum, the distributor uses it.
It doesn't matter how the carby's plugged ( on the carby on the other end of the vac line) so long as it's the carby which is plugged, not the distributor.
Dave wrote -
The book is not specific -- it just says "plug the line". And so I did -- on the wrong end!
Rob responded -
A nice laugh. That's what we are trying to do with the Joe Shadetree aren't we -- avoid ANY ambiguity.

A final thought from Rob -
If I ever need to replace my distributor, I'll probably be going for one of these SVDA types too. I suspect it will work just a little better than the vac-only unit I have at present. The only concern I have with them for my car is that the rate of centrifugal advance (the 009 part of it) may be slightly different to the vac-only rate of advance at each point in the rev range, which may change the engine acceleration characteristics a little, since it's a single port 1600, with different head/gas dynamics to the tp1600. And the 30PICT/2 carby produces a different flow rate through the venturi than the larger throat 34. It will be interesting to find out if any difference is noticeable.

Vacuum Distributor Test


To determine for sure which vacuum line is working and which isn't:
1. Put the timing light on and rev the engine up to a steady spead (1500 2000 rpm). Then 'blip' the throttle open and let it go so that the revs don't change much but the load does. If the advance vacuum line is working, I should see an immediate change in the advance, before the engine revs change much, and then a rapid change back again as the throttle is released. If the advance vacuum line is NOT working, there will only be a steady change as the revs increase the advance won't 'blip' with the throttle movement itself.
To put it another way, if the engine revs alter by say 500rpm as I 'blip' the throttle, I should see a timing change of maybe 2 3 degrees caused by the centrifugal advance. But if the vac line is working, you should see it rapidly advance by maybe 8 10 degrees as the throttle arm is moved.
2. Then run the engine at 3000 3500 and check the timing. If my theories (and Rob's) are correct, It should be AT LEAST 30 degrees or more (30 degrees if only the centrifugal is working more if the vac advance is working too).
3. If it's less than 30 degrees, then I'll disconnect both vac lines at the carby and plug them, then adjust the timing for 30 degrees at 3000rpm (this means setting it using just the centrifugal advance), then reconnect both vac lines.
4. Then drop the revs back to idle and look at the timing again. It should be 5ATDC or thereabouts. If so, the retard vac line is working OK. But if its somewhere from 0 to 10BTDC at idle, then I would guess is that it's the RETARD line which is not working.
5. Having confirmed that the retard vac line is working, then I will gently open the throttle with the timing light still on the timing should change rapidly from 5ATDC to some positive figure as the retard line stops working.
6. Re time the engine properly after doing the test (5ATDC at idle).


 

Distributor Questions and Answers


All responses are from Rob Boardman unless otherwise indicated.
Question -
Ever since I came into the VW scene (about 2 yrs) I've been hearing people going on and on and on for the 009. Where the heck did it come from? Was it a stock part for certain VW's? And what difference will it make on my 1969 1300sp engine. Oh yeah, and what's that "flat spot" all about?. I'm VERY confused and I hope you fellow fweemers can sort it out for me (and other newcomers).
Response -
VW built a lot of industrial engines (called type 122 for the 1200 and 124 for the 1600) as well as those built for the beetle itself.
Industrial engines powering generators, compressors and such are near enough to constant speed, so only a simple distributor was needed. So a centrifugal distributor was developed by VW, and later by Bosch. This type of distributor increases the amount of advance as the engine speed rises, but can not sense the throttle position (engine load). This is fine for engines operating at constant speeds, or at high power and high rpm (for VW racing engines for example, plus the previously mentioned industrial engines).
When the first type2 (Kombi etc) vehicles came out (1954 I think), they used the 1200 VW engine and needed reduction hubs so that the tiny engine could push a heavy vehicle (with a top speed of about 85kmh since the reduction hubs meant it was revving it's heart out!).
Because these engines in the type2 were working at high rpm and high throttle most of their life, the VW version of the centrifugal distributor was used on them too (but just try getting one off the line - they needed a lot of revs and clutch slip to avoid bogging down).

Most engines in road vehicles operate at various engine rpm and load conditions, which requires a lot of variation in the amount of advance needed for optimum engine performance and economy.
So most road vehicles use vacuum sensing, or a combination of vacuum and centrifugal, to get the best timing over a wide range of engine operations.
The early beetles used single vacuum distributors; there is a version of double vacuum distributor (for emissions reasons) for the 71-73 beetles in some countries only; and from 74 onwards VW used a combination distributor - like a 009 with added vacuum advance.
These distributors are quite expensive to build in comparison with the Bosch 009 (the Bosch equivalent of the VW centrifugal distributor). So the cheap-to-build Bosch 009 became a sort of "common" replacement distributor, since it IS so cheap, and it does work (sort of). But it's a "one size fits all" distributor, so it's NOT ideal, and it can cause problems for some engine/carby set-ups.
To accelerate an engine smoothly, you need both extra fuel and a shot of advance. The accelerator pump provides the extra fuel and the vacuum distributors provide the additional advance needed. But a 009 cannot provide any advance until AFTER the engine rpm starts to increase (actually from about 1200rpm) so, if the carby is set to run a little lean (LESS fuel), you get a hesitation or flat spot, which usually means the driver has to blip the throttle a time or two to get the rpm up to the point where the 009 is starting to advance, then "feather" the throttle (and slip the clutch) so the rpm stays high, to avoid that flat spot.

The most common technique to overcome the 009 flat spot is to replace that "missing" advance with extra fuel - a larger main jet, max stroke on the accelerator pump, and in some cases filling in the air-bleed hole in the throttle butterfly.
The earlier Solex carburettors (28PCI, 28PICT and 30PICT/1 and /2) are set to run a little on the rich side - the VW engine actually likes 13.8:1 air/fuel ratio, where the ideal is 14.5:1). So since these carbies are set to run rich anyway, the flat spot is often not noticeable, or can be tuned out with minor adjustments.
But in 1970/71 the emissions problem was becoming recognised and VW changed the jetting on the 30PICT/3 (1970 US only) and the 34PICT/3, and /4 to run the carby leaner - closer to the ideal 14.5:1 air/fuel ratio (the California 34PICT/4 uses a main jet which is about 6 sizes smaller than "normal"!).
So with this leaner running carby set-up, the 009 flat spot becomes a real issue.
You'll hear most complaints from folks who use the 34PICT/3, 34PICT/4 or the modern equivalent for the smaller carbs - the Brosol H30/31 (which is almost identical to the 1970 30PICT/3) - all of which normally come with lean jetting.
Your 1969 1300 with 30PICT/2 carby is one of the older variety carbies with slightly richer settings so you would not notice the 009 flat spot so much (if at all).
Another issue with the 009 is the limited maximum advance. The vacuum distributors can run up to about 40-42 degrees under the right conditions (light throttle and medium speeds for example) and this helps fuel economy. But if you maintained that much advance with a full throttle and low/medium rpm, the engine would ping/detonate. The reason is rather technical, but is mainly related to the amount of residual exhaust gases which are left in the cylinder compared to the incoming charge. There is always SOME residual gases, since there's a head space above the cylinder. At part throttle there is a proportionally larger amount of burned gases in comparison to the fresh stuff (throttled fresh mixture but same head space of burned stuff) - at full throttle there's a lower proportion of burned gases because you are letting in MORE fresh mixture for the fixed volume of head space. This "contamination" of the fresh mixture alters the flame speed (the time it takes for the fuel/air mixture to burn) so open throttle needs less advance (burns faster) and part throttle needs more advance (burns slower) - at any particular rpm.
(Incidentally, this is part of the reason why the low compression 1200s need more advance - usually 10BTDC compared to 7.5 BTDC for most 1500/1600s). Low compression means more head space (compared to the cylinder volume), and so there is more contamination of the fresh charge throughout the rpm range and that means a little more advance is needed so all the fuel is burned just as the piston starts it's descent.
The vacuum distributor senses throttle position, so if you floor the throttle at low-medium speeds, the distributor is able to "back off" the advance until the engine speed catches up with the new throttle position (slowly allowing the extra advance back in as the rpm rises), but the 009 cant do this, so it HAS to be set to "worst case" which is between 28 and 32 degrees at 25-2600+rpm (which is why we set the 009 at 3000rpm - to make sure that all the advance is present).
Since the 009 has been limited to 28-32 degrees compared to the vacuum distributor's 40-42, it's actually UNDER-ADVANCED for a lot of driving conditions, and this means worse fuel economy. And because you need to set the carby to run rich to reduce the flat spots, fuel economy suffers even more.
Because the 009 is built very cheaply, the total amount of advance varies from one to the next. This means when setting the 009, it's important to set it at max rpm, not idle, since the max advance is much more important for most engine conditions. Always use as much of the 28-32 as the engine can take without pining/detonating, as this will reduce any flat spots just a little, and also help fuel economy just a little. If it still pings at 28 degrees, always use a higher octane fuel, NEVER use less than 28 degrees because it means the engine is seriously underadvanced at higher rpm and will run hotter than it needs to.
Once you have determined the maximum advance which works well for your 009, you can then measure the idle advance (which will probably be between 5 and 10 BTDC) and you can then use THAT setting for THAT 009 to set it at idle or static if you want to.
So you can see that the 009 is NOT ideal, but it will work. For best performance under all engine operating conditions, you need a vacuum distributor.
Hope all that makes sense.
There are tune-up articles on our web site which include info on both vacuum and 009 distributor settings.
Question -
I'm having a problem with my car. The other day I went down and washed my engine. Now it won't start. I used my manuals and the coils still strong, the distributors working. I pulled the spark plugs and replaced them all. I tested them out of the engine and they are sparking just fine. So now I'm questioning the fuel system. The pumps working fine. I pulled the air cleaner but no gas is coming from the carb into the throat. (I'm guessing the gas comes from that pipe from the top of the carb once the air cleaner is removed, the one above the first butterfly valve) I have a brand new battery and the starter is turning the engine over. Also gas is coming out of the bottom of the engine from unknown location. I tried to pore a little gas into the carb but no firing... How could washing the engine screw this up so bad! I could use some help.
Response -
VWs hate wet distributors and will leak the spark to ground very easily. At night you can try getting a friend to crank the engine and look for sparks over the dizzy cap (interesting when you see this - quite pretty!). Try removing the centre electrode from the cap and wiping around it with a dry cloth/tissue. Same thing with the coil - make sure the area around the centre connector is very clean and dry. Replace and test for spark with the spark plug end of one wire and a spare plug - held against the engine casing (you'll need a friend to crank the engine a couple of times). The spark is much easier to see in the shade or at night. Be very careful you don't tangle with the fan belt/pulleys when working near a turning engine.

If no spark, also check for 12v at the coil (on the + side). If you don't have a voltmeter, just use any 12v globe and connect to the + side of the coil and to ground (engine case), and turn the ignition on. If the light glows, then the coil is getting power. If your car has reversing lights, this test can be done by putting the car in reverse and turning on the ignition, since the reversing lights get there power from the 12v connector on the coil (the 66 didn't originally have reversing lights though).
Also try removing the cap and wiping it inside with a dry cloth - even a tiny mist of water there will cause problems. If there IS a little moisture inside, dry the points too (not as sensitive as the cap since the points only see 12v, and the cap sees 18,000 volts), but still useful sometimes to dry the whole thing with a hair drier etc if needed. You could also try spraying copious amounts of WD40 around to disperse the water, but this will cause a mess in itself, and a dust trap later on.
Question -
(My engine) idles perfectly, if you step on the gas, the engine coughs and sputters before revving up. Could that be caused by the distributor?
Response -
The distributor, or a combination of distributor and the carby.
Question continued -
I spent all day messing with the mixture screw. It does it at every setting from as far in as the screw can be while still running to the screw practically falling out of the carb.
Response -
Do you get any variation in the idle when you play with the screw? If not then the idle jets themselves may be blocked.
Question continued -
So I'm pretty sure the problem isn't the mixture. I just changed the distributor from a 009 to a stock vacuum advance, could the vacuum advance distributor be crap and be causing this problem?
Response -
It's possible. You can check the vacuum arm operation very easily - take the cap off the dizzy so you can see the points plate, take the vacuum line off the carby, and suck on it. The points plate should move and then stay put if you cover the tube with your tongue. If it drifts back the diaphragm is holed and it won't pull in advance like it should (not as fast anyway).
I forget exactly what carby you had on too - the vacuum distributor does not need as rich a mixture ( can use smaller jets) compared to the 009, but if the richer ones are in their, then you should not get the hesitation anyway. You have the vacuum line connected to the port on the left side of the carby - just above the throttle arm?
You should have the idle set at 10BTDC (static) for the vacuum distributor on that engine.
Oh - and I presume the vacuum canister is the old variety, with an adjusting nut in the middle of it? There are several types of vacuum canister, to suit the different vacuum signals from different sized carburettors. I'm no expert on the 36hp engine, but I know it had an adjustable vacuum diaphragm.
Have you checked the operation of the vacuum canister? Remove the vacuum pipe from the left side of the carby (the vacuum point just above the throttle shaft is the advance vacuum line) and with the top off the distributor, suck on the vacuum line (still connected to the vacuum canister). You should see the vacuum arm move and it should stay put if you then cover the vacuum pipe with your tongue. If it doesn't move the vacuum canister is shot of sticking, and if it drifts back when blocked then the diaphragm is holed - it will still work (sort of) but will then stumble as you try to accelerate.
If your car has a single vacuum canister (only one vacuum line to the canister on the carby), then as I said above this must be connected to the left side vacuum port. Any vacuum ports on the rear (rear of car) of the carby must be plugged - they are not used with single vacuum distributors (double vacuum distributors were used mostly in the USA and DO use the rear vacuum ports on the carby).
Question -
The cam duration is marginally more than stock, will the distributor advance correctly?
Response -
It should be OK, since as you say you will have a larger capacity feeding through the same carb - you should have a good airflow for good vacuum signal. With the SVDA type distributor you have, the vacuum is only providing about 8 degrees of the advance and the centrifgual part the other 30 degrees or so, so a fractional difference in the rate of advance should not be noticable.
It's certainly another reason for sticking to a mild cam though - too much overlap and you won't get that early vacuum advance kicking in properly.
Bob Hoover wrote -
VW distributors are not well sealed. There is always some amount of oil vapor inside the unit. Combined with the carbon granules that wear off the central button in the distributor cap,over time this obscures the IR pickup on the optical sensor and results in misfires.
Someone responded -
Of course, VW did include a dust shield in their later distributors which would help the carbon granule problem immensely. The Haynes and Chilton's manuals both show a plastic shield which sits on the rim of the distributor body, held in place by the cap. The hole in the middle is hardly larder than the shaft of the rotor, and any carbon granules from the carbon button would have a hard time finding their way through the gap in between.
However, my own distributor aside, I have yet to see *any* aircooled VW with its shield still in place (though admittedly, I haven't looked under *that* many distributor caps ) They seem to fall victim to the "runs fine without it there, so throw it out" mentailty at some point in most cars' histories. Watercooled VW's have similar distributors, and guess what? They have the same dust shield too. In fact, the dust shield, distributor cap, rotor, and anti static shield from many Watercooled VW's fit just fine on the later aircooled distributors.
The caps I saw on the watercooled VW's at the local salvage yard were the exact same part number as the cap I already had on my distributor. The one rotor I brought back as a sample was somewhat different though. Fits just fine, but has a resistance of 1K instead of 5K (this offset partly by the fact that extra resistance was designed into the spark plug wire connector at the distributor cap, and more by the factory use of carbon wires rather than copper). John C has mentioned that the stock rotor sometimes dies over time with the extra energy from a CDI. I think one of the 1K watercooled rotors may survive better, and save the trouble of digging out the epoxy and soldering in a chunk of brass as John suggests.
Dave wrote -
I'm guilty! I'm a heretic!! I did the unthinkable! I put the 009 dizzy back in!
I static timed it and took it out for a test drive. Pretty good -- better than the vacuum dizzy, I have to say. So I backed it into and slapped the timing light on it. It was just a tad advanced, so I turned the dizzy back just a titch. Revved it up, and right up to my 30-32 degree mark it went. Took it out again -- the car has NEVER run better!
Rob responded -
OK, so now we know there probably IS a fault in the double vac unit. So is it the retard vac in the canister, or the points plate sticking? I guess you could check the points plate by disconnecting the vac actuating arm and seeing if the plate moves freely through it's range. If so, it must be the canister. THIS should be findable (new of course -- second hand would be just asking for the problem again). I can buy vac canisters over the counter here (pricey but available), so they MUST be available there somewhere.
You could also try using the vac unit as a single vac, and see if that gets rid of more of the hestitation. It still may not be perfect of course, because the carby tuning is really set up for the idle retard, but it might come very close.
Dave wrote -
I can go around a corner in second gear with out even touching the clutch -- not even a hint of hesitation. It still revs a little before taking hold ...
Rob responded -
That's the 009 centrifugal only advance for sure.
Dave wrote -
My conclusion from all this is that my vacuum distributor is defective. That's the only conclusion that makes sense, because I remain convinced that the double vac dizzy is the one that should be used with the 34-PICT/3 carby. Maybe I'll be able to fix it, like Bob Hoover recommends, but junked VWs are almost impossible to find around here.
Rob responded - As I said, if you can get a new vac canister, and the points plate works OK, that may be all you need. Alternatively, Bob Hoover says the spacing washers from a 009 make dandy spacing washers to fix the free play in vacuum units.

Dave wrote - Well, I did it. I ordered a Single Vacuum Dual Advance (SVDA)distributor ...<.P> I backed the Bug into the garage and pulled the 009 distributor out of it. Then I put the new SVDA dizzy in -- a VERY tight fit. I had to remove the bracket and then gently persuade it over the seal and onto the shaft, then push and push to get the shaft down into the hole. This is good -- we certainly shouldn't be getting anymore oil leakage! How some ever -- I'm confused. The #1 notch on the rim of the distributor ends up being at about 1 o'clock, which I've never heard of before -- it's supposed to be at 5 o'clock.

Rob responded - Yes that's correct -- should be about 5 o'clock. But I seem to remember you saying the 009 had #1 cylinder in the 1 o'clock too, so it may be that the camshaft has been inserted wrong. If this is the case it shouldn't matter so long as the plug leads are fitted appropriately.

Dave wrote - I went ahead and attached the wires that way -- 1-2-3-4 around the distributor counterclockwise (opposite the way it runs).
Rob responded -
Firing order is 1432, so if you start at 1 o'clock, the connections on the dizzy would be --
2 1
0
3 4
I think that's the same as you described above.
Dave wrote -
Then I static timed it, started it up and timed it with the timing light (the static timing was right on). It purrs like a kitten in the driveway, but it doesn't run any better on the road -- in fact, I think it's worse -- it always hesitates when I goose it and when I let out the clutch after turning a corner.
Rob responded -
Could just be the tuning is wrong for the new distributor -- other than that I'm not sure.
Dave wrote -
There's got to be something basically wrong here that I'm overlooking. The fact that #1 is at 1 o'clock on the distributor is weird and makes me very suspicious. I think that the firing sequence is all screwed up, but I'm not smart enough to know how to test it and correct it. I suspect I should pull the #1 plug and make sure it's at TDC when the notch on the pulley lines up with the split in the crankcase -- THEN put the distributor in and see where the rotor points. I think I'm 180 degrees out of phase or something.
Rob responded -
That's possible. Yes -- pull the #1 plug and the right rocker cover. Find TDC with BOTH valves shut (loose) -- this will be the firing stroke for #1, and see where the rotor is pointing. That will be your starting point. Once you have #1 the others will follow the correct sequence.
Dave wrote -
It seems to be possible to put the drive shaft back in any old way, as long as it engages the crankshaft gear. That would explain a LOT!
Rob responded -
Could just be the tuning is wrong for the new distributor.
Dave wrote -
Could you be just a little more precise? What aspect of the "tuning" may be wrong? What should I experiement with? Different point settings? The timing? Idle?
Rob responded -
I was thinking of the carby settings -- it runs better with richer settings for the 009, maybe too rich for the single vacuum dizzy? Could try a little less squirt on the accel pump, and adjusting the volume screw (smaller one).
Dave wrote to John Connolly -
I have successfully installed the SVDA Distributor you sent me, and the car is running very well.
However, I have a question -- I am confused by the fact that the notch for the #1 cylinder is at about 1 o'clock on the distributor rim -- according to the manuals it's supposed to be at about 5 o'clock. I have verified that the #1 piston is at TDC with the pulley at the TDC mark and the rotor pointing to the notch on the distributor rim. The valves are closed, so I know that #1 is at TDC.
John responded -
That distributor came out of a type 4 engine, that's all. Since there is no retard on #3, you just wire it up. Make SURE you don't have plug wires crossing one another, that's asking for trouble.
Dave wrote -
My distributor driveshaft is a little bit cockeyed, but I don't think that should make a difference as long as the spark plug wires are attached properly (counterclockwise from the notch, 1 2 3 4; firing order 1 4 3 2).
I would appreciate any advice -- this situation seems a little strange (though the car is running better than it ever has before).
Dave wrote to John -
I found that 1 & 2 and 3 & 4 were crossed; I corrected that, and it DID make a difference. I was not aware that that could be a problem, and I doubt that many VW owners are.
John responded -
Now I need to convince you to the Pertronix and CDI. Next step up in the running good process.
Dave wrote -
I've been interested in the Pertronix system for some time. Is there some place on the Internet where I might learn more about it; e.g., performance, installation, etc.?
John responded -
Read the tech articles on our site (Aircooled.Net), especially the bolt on mods (the first one). They are easy to install (about an hour total).
Rob wrote -
I had a chat with my mechanic friend at Intervolks this morning. Apparently we can't get single vac dizzies any more in Aus, although replacement vac canisters can still be obtained (just over $50). the 009 here cost about $130, which is about right with exchange rates and freight. He didn't know the SVDA was available anywhere, so I told him about aircooled.net. He's using a 009 on his 69 1500 with 30PICT carby, says it runs great after altering the jets in the carby. We know that story don't we! As we know, the 30s cope with the 009 better than the 34s anyway.
Someone wrote -
The cam duration is marginally more than stock, will the distributor advance correctly?
Rob responded -
It should be OK, since as you say you will have a larger capacity feeding through the same carb - you should have a good airflow for good vacuum signal. With the SVDA type distributor you have, the vacuum is only providing about 8 degrees of the advance and the centrifgual part the other 30 degrees or so, so a fractional difference in the rate of advance should not be noticable. It's certainly another reason for sticking to a mild cam though - too much overlap and you won't get that early vacuum advance kicking in properly.
Someone wrote -
I guess I should have said it idles perfectly, if you step on the gas, the engine coughs and sputters before revving up. Could that be caused by the distributor?
Rob responded -
The distributor, or a combination of distributor and the carby.
Question -
I spent all day messing with the mixture screw. It does it at every setting from as far in as the screw can be while still running to the screw practically falling out of the carb.
Response -
Do you get any variation in the idle when you play with the screw? If not then the idle jets themselves may be blocked.
Question continued -
So I'm pretty sure the problem isn't the mixture. I just changed the distributor from a 009 to a stock vacuum advance, could the vacuum advance distributor be crap and be causing this problem?
Response -
It's possible. You can check the vacuum arm operation very easily - take the cap off the dizzy so you can see the points plate, take the vacuum line off the carby, and suck on it. The points plate should move and then stay put if you cover the tube with your tongue. If it drifts back the diaphragm is holed and it won't pull in advance like it should (not as fast anyway).
I forget exactly what carby you had on too - the vacuum distributor does not need as rich a mixture ( can use smaller jets) compared to the 009, but if the richer ones are in their, then you should not get the hesitation anyway. You have the vacuum line connected to the port on the left side of the carby - just above the throttle arm?
You should have the idle set at 10BTDC (static) for the vacuum distributor on that engine.
Oh - and I presume the vacuum canister is the old variety, with an adjusting nut in the middle of it? There are several types of vacuum canister, to suit the different vacuum signals from different sized carburettors. I'm no expert on the 36hp engine, but I know it had an adjustable vacuum diaphragm.
 

Ignition Wires and Spark Plugs

NOTE: Regarding the "reading" of spark plugs, please see the Spark Plug article.

Misfiring

A question is often asked about why the engine “shakes” at idle.

Rob gives several possible reason for the “shakes” -- those pertinent to wires and plugs are as follows -

A wobbling engine usually means one cylinder is not firing properly.

Here are some things you can check -

1.     Spark Plugs -- Sometimes a spark plug will not work well as idle but will work OK when the engine is running faster. Pertonix Ignition may help, as the Pertronix ignitor usually makes better sparks at low speeds than the standard ignition.

2.     Spark Plug Wires -- Make sure the spark plug wires are not shorting out. You may be able to see this arcing on a dark night with the engine running. If you have Pertronix ignition, a hotter spark is produced that will jump through old spark plug wires.

3.     Low Compression -- (See our discussion of engine diagnostics for a compression test procedure.)

4.     Carburetor Shut-Off Solenoid -- (See our discussion of engine wobble for a check of the shut-off solenoid.)

5.     Air Leakage Into the Intake Manifold -- (See our air inleakage discussion.)

Test for Cylinder Mis-Firing -

(Sometimes called a “power balance” test.) This test provides a good indication of how much each cylinder contributes to the overall power output of the engine. In addition, it also isolates which cylinders contribute little to manifold vacuum.

You can perform this test at home on any VW engine except those with electronic ignition. If there is a suspected burned valve or other major problem, this quick and easy test will indicate which cylinder it is. Because VWs have only four cylinders, a faulty one will show up relatively quickly.
To perform a cylinder mis-firing test -
1. Remove all the spark plug leads from the spark plugs.
2. Set the leads lightly back on the tops of the spark plugs. This will enable the lifting of each lead off its plug without using too much force.
3. Pull the lead away from the plug one cylinder at a time, and ground the lead against the cylinder head. This will prevent that cylinder from firing. The engine will be running on only three cylinders as you test each cylinder sequentially.
4. As you disable each cylinder, listen to the change in engine rpm and performance.
If a cylinder is faulty, when it is disabled it will have little or no effect on the engine’s speed or performance, as it will not be contributing fully to the overall engine power.
A dwell-tachometer will give a more accurate indication of changes in engine rpm as you conduct the test.
 

Ignition Wires

I would stick with the stock type ignition wires as they often have a lower resistance than silicone wires with graphite leads.
Rob reports -
My original set (of spark plug wires) stayed in the car 18 years till they became hardened and brittle. (Dave, being obsessive and ultra-conservative, replaced his after only two years.)
Dave wrote to John Connolly (Aircooled.Net) with regard to ignition wires to be used with a CDI system -
I'm still not clear about the plug wires for use with the CDI system. Some say the sturdier wires (i.e., Jacob's or Megavolt) are necessary; others say the stock wires are just fine (mine are almost new -- I'm loath to replace them already).
John responded -
If they are almost new, don't change them. However, give them a check once in a while, because the additional spark energy can break them down quicker than with the stock ignition (weak).
 

Spark Plugs

Someone on the RAMVA Newsgroup wrote -
NGK's are the better of any commonly available plugs, and can be cleaned with a wire brush, for so being re-gapped.
>
Dave wrote to Rob -
The Bug is starting to run rough. I think its those cheap Champion plugs I put in (just because they were hanging around my work bench) a few months ago. Tonight I'm going to let my fingers to the walking through the Yellow Pages and try to find a set of the NGK plugs--B5HS for the 12mm ones, if memory serves.
Rob responded -
B5HS is the standard electrode plug. These are the ones I'm using, and they are working well, but only 1000 miles or so on them, so time will tell.
B5HY is the equivalent grooved electrode version, and I'll try to find a set of these at next replacement time too, for comparison.
In NG parlance, B is the thread size 14m (A=18mm, C=10mm), 5 is the heat range (2 is hottest, 13 is coldest), H is thread length 12 mm (# for 19mm), and S is standard electrode (Y=grooved, V=precious metals, VX=platinum, etc) and you might come across an additional letter for the plug gap (9 for .9mm, 10 for 1mm, 11 for 1.1mm, and 13 for 1.3mm; but not on the plugs suitable for VW as far as I know.)
Rob wrote regarding grooved electrodes -
The multiple electrodes tend to shield the spark from the mixture a little, which is OK in a slow revving aircraft engine, but not so good in a higher revving auto engine. Then they developed a "surface electrode" type, which had the cavity filled with bakelite or similar, and the spark jumped from inward facing 'bumps' on the rim to the inner electrode, all of which were flush with the bakelite filling the cavity. Supposed to be harder to clog, because there was no cavity to hold the gunk. Not even used in cars to my knowledge. NGK do make a grooved electrode plug though, and this is supposed to make the spark on the outer edge of the side electrode, instead of jumping to the center electrode right in the middle. Supposed to eliminate any possible shielding of the spark more exposure to the fuel/air mix.
Rob wrote in response to a query -
The VW engine works best with Bosch WA8C or NGK B5HS plugs. (Champion L87Ys are the right heat range too, but they have cut threads not rolled and tend to strip out the aluminium heads.) You can do a plug test by running down the road at a good speed (with the engine properly warmed up), and shutting off/declutching/tuning engine off in the middle of the run, and coasting to a stop. This is necessary so the reading is not contaminated by any idling.
The plugs should have a grey/black thin coating on the rim of the threaded section. The centre porcelain insulator should be off white, turning darker deeper into the plug (about 1/2 way down the insulator) and the tips of the outer electrodes should be grey/white, turning darker on the bend, to blend into the dark grey of the rim of the plug. Black/oily is a good indicator of a worn engine. Black/sooty means it's running too rich. Brown /whitish insulator and a 'white all over' outer electrode usually indicates lean running, often accompanied by a light coloured rim on the plug. If the rim has a speckled "pizza" appearance, the engine is detonating (even if you can't hear it), and you try a different brand of fuel of go to the next higher octane fuel. And of course if the centre electrode has rounded edges instead of a 'squared off' end, and the outer electrodes are looking thin and burned, the plugs are past their best and should be replaced.
If you can avoid using oxygenated (MTBE) fuels do so, your engine will run smoother. Oxygenates result in less "fuel" in the fuel, and make old carburetted cars like the beetle run lean, which means running hotter, and they don't like running hotter since they are a hot running engine anyway. If you don't have a choice, try switching brands, and DO use a "pump octane" of at least 87 maybe higher if it needs it to avoid detonation.
Rob responded to another query -
Just to check, are your old plugs the 1/2 thread, or the longer 3/4 inch thread? If your car has the newer style replacement heads (they are interchangeable), they will need the 3/4" plugs B5ES ("E" for "extended" thread).
With the engine out, it might be possible to shine a torch down a plug hole and check. If the heads are the newer 3/4 inch type, and you have 1/2 inch plugs in them, you'd see a blackened section of unused thread at the bottom of the hole. The short plugs will fire in the newer heads, but less efficiently, as they will be "buried" inside the heads.
Dave asked of John Connolly (Aircooled.Net) -
I'm running NGK plugs that are less than six months and 1000 miles old -- can I clean them up, gap them to 0.040", and reuse them (with a CDI system)?
John's short response -
Yes.

Spark Plugs in CDI Systems

Rob wrote in response to a query regarding spark plugs in CDI systems -
The regular plugs should be OK. B5HS is right. Widen the gap a little from the normal, and there is a possibility that the STANDARD plug leads will occasionally arch, since they are running at 38,000 volts in lieu of the normal 20,000.
As a start, make sure the distributor cap is clean and dust free, but before you clean it, have a look at it at night with the engine running. It's a common arching point (between the rubber caps) - you can see any arching at night.
If it's arching there, it may just need the thicker (insulated) leads, and an occasional wipe of the distributor cap.
Dave asked -
I wonder if I don't need to be running hotter plugs, since the CDI system almost doubles the voltage across them.
Rob responded -
The plug "heat" is actually a function of the cylinder head temp more than anything. A "hot" plug retains heat in the centre electrode longer than a "cold" plug. A hot plug has a long centre electrode - the join to the shell of the plug it deep inside the plug. VWs need a coldish plug to counter the fact that they are shedding heat into a hotter than normal head. So is the NGK B5HS a "coldish" plug.
Dave's question continued -
The bottom line on the spark plugs, then, is NGK B5HS with a .040" gap. Just wanted to make sure that you concur.
Rob responded -
Yes. But as I said, if the misfire continues, suspect the leads and a dirty (doesn't have to be much) cap first. Oh - and clean the inside of the cap too, if it doesn't look shiny clean.
Rob wrote -
There is a possibility that the STANDARD plug leads will occasionally arc.
They are sometimes described as high tension plug leads, or 8mm plug leads (thicker insulation) - but I don't know what they'd call them in the US.
You had new standard leads I remember, and these SHOULD be OK, so hopefully a good clean around the cap and maybe the leads too might be enough.
 

Miscellaneous Questions and Answers

All responses are from Rob Boardman unless otherwise indicated.
Question -
When I couldn't start the car the other day, I had to leave the car at the wash. I disconnected the spark plug wires to deter thieves. When I got there the next morning I put them on the wrong cylinders! So, I pushed the car 1/2 miles to my house over mixed up wires!
Response -
I'm not laughing -- it's easy enough to do, and a hell of a good lesson in the school of hard knocks.
One trick I found useful for this was to put a twist of copper wire around the spark plug leads near the plug ends. One turn for No1 cylinder, twice around for No2 and so on. Can't mix them up then unless you remove the wires from the distributor too.
Question -
I own a 1968 model beetle which is a 12V one. I would like to enquire regarding its spark plugs and hope that you don't mind.
In one of your articles, I noted that you mentioned NGK plugs B5HS. Here in my home town, I can't get them but the dealer told me to use B6SS. Is it OK and what does the figures on the plugs indicates such as 5 or 6. My plugs also appears to be black/oily and what does it indicates.
Response -
I have the NGK Spark Plug Guide in front of me...
The NGK letters and numbers mean -
B - 14mm plug (A-18mm, C-10mm etc)
5 - heat range - 2 is very hot, 13 is very cold.
H - thread length 12.7mm (E for 19mm)
S - "standard" electrode type (Y for grooved, P for platinum etc)
The 6 heat rating should be OK - it's just a fraction "colder" than the 5, and should be OK in your hotter climate. "Colder" for a spark plug means that it gets rid of heat faster than a "hot" plug.
But you said B6SS - the character after the number should only be an H or E indicating the length of the threads. There is no S length - only H and E. If you really meant B6HS, then yes - that should be fine.
Black and oily usually means that the engine is starting to burn a little oil (starting to get worn). If you use a colder plug (the B6HS) there is a possibility that they will oil up more, but there's no way of telling untill you try them and see if they oil up too fast and stop working.
If the deposits were black-sooty I would say that it's just running a little rich, but black-oily usually means it's burning a little oil, so you might keep a check on the oil level too, just to make sure it's not using too much between oil changes.
Rob commented -
I changed the spark plugs on the weekend.
The old ones are Bosch W8AC and all were in quite good condition for 12000+ miles. Nice to see that all plugs looked the same - all cylinders performing about the same.
I might take a close up photo as an example of the correct heat range (clean ceramic centre post, black rim and colour change from grey to black on the outer electrode, right on the bend.)
It will be interesting to see if the NKGs (replacements) look any different after they have done the same miles.
Question -
After I had picked up the vehicle I noticed it pinging under acceleration… (Mechanic) sent me on my way stating that if I was not happy to bring it back to him again and he will try a different set of spark plugs.
Response -
Changing spark plugs will not cure pinging/detonation. Only timing and choice of fuel would have any effect there, since we are not talking about altering the compression ratio (the only other consideration in eliminating detonation).
You can get a lot of other useful information about type2 VWs at
www.vitangebus.com and www.type2.com.
 

Our friend Leo in Venezuela wrote -
So now I'm in a new little project on my car..... he spit away a spark plug, so I had the thread fixed an made the job on three sparks.
The fact is that the fourth one had already this job done, and spit last week the spark plug again but with the copper threaded insert, so I think it was a rebuilt head....
Response -
That's unfortunate, but it can happen with old heads - the thread is only aluminium so rough handling in the past could have damaged the threads. I always use Bosch or NGK spark plugs because of this - they have smooth threads. Some other brands have sharp threads which damage the heads more easily.
 

Capacitive Discharge Ignition (CDI)


Material gleaned from various VW newsgroup conversations and direct e-mail correspondence.
A conventional induction ignition creates a spark by applying electric potential (12 volts) to the primary side of the coil. The coil steps the primary potential up to as much as 10,000 volts and delivers this high voltage to the spark plugs. However, this "step up" process is relatively slow, and as crank speed (rpm) increases, the secondary voltage declines dramatically.
This limitation was partially solved by the development of capacitive-discharge ignition (CDI) systems. Instead of applying 12 volts to the coil, a CD ignition increases the primary current by storing it in a kind of miniature battery called a capacitor. When this higher primary current is applied to the coil, the secondary voltage is dramatically increased.
The principal advantage of a CDI system is the ability to present a superior spark to the air/fuel mixture inside the combustion chamber, thus maximizing burn efficiency. The easiest way to get a bigger spark is to increase the spark plug gap size. However, increasing the gap distance also increases the voltage necessary to ionize the air/fuel mixture. And the resistance of the air/fuel mixture increases as the mixture is pressurized in the cylinder, requiring even higher voltage to spark across a plug. A CDI system provides the higher voltage required by the increased spark plug gap size, thus providing very intense spark.
A CDI ignition system can create spark potential as high as 37,000 volts. Most engines only need about 20,000 volts for reliable ignition. The stock system begins to 'droop' as the rpm goes up. At highway speeds, the spark voltage becomes more and more marginal, averaging about 18,000 volts. With a CDI system, the step up process is very fast compared to a conventional 12-volt induction. This assures a more consistent spark delivery across the plug gap, even at very high crank speeds (rpm).

A note -- the consistently higher voltage will cause neoprene-type insulation to break down rather rapidly. You need sparkplug wires with better insulation, such as silicone or non-metallic.
The carbon conductor in the non-metallic leads will produce less radio interference and won't corrode like metallic leads. Electrically, if you've got 37000 volts available, the ignition system can't tell the difference between metallic & non-metallic leads.
We recommend NGK spark plugs, gapped to 0.040 inch. (See our tune-up procedures for more detail regarding spark plug removal and reinstallation.
A note from Bob Hoover -- The CDI module doesn't claim to be anything special, just a good basic ignition system. If all you want is a good, reliable ride, it's the best idea since beer in cans. It will save you money, help clean up the environment and make your car run better, all at the same time.
Rob wrote regarding the CDI system -
The CDI ignition kit DOES help with cold starts and fractionally better economy. The plugs DO last longer too. The one I built many years ago worked well with the standard plug wires, but I suppose the more modern ones would need better wires for the higher voltages they generate.
Question -
Isn't the points triggered CDI different than the electronic points replacement CDI? I know they sell two different ones. Just trying to save someone from having to buy two. But, I could be wrong, sure wouldn't be the first time.
Bob Hoover responded -
Two types of CDI units are offered -- a points-triggered CDI module and an optically-triggered CDI module.
VW distributors are not well sealed. There is always some amount of oil vapor inside the unit. Combined with the carbon granules that wear off the central button in the distributor cap, over time this obscures the IR pickup on the optical sensor and results in misfires. It doesn't happen suddenly you get some warning that things aren't working right and a Q tip soaked in alcohol cleans it right up... but there's plenty of times, such as when you're in freeway traffic, when you just can't afford to have your engine start missing.
The points triggered module is designed to trigger off the stock points and works equally well when triggered by an electronic switch that uses magnetic sensing, such as the Pertronix.
The basic circuit in the CDI module -- the 'singing aluminum brick' you mount on your firewall or wherever, stays the same no matter what method of triggering is used. The two modules (points-triggered and optically-triggered) are not interchangeable without going inside the unit and resoldering some wires.
The stock points work okay for triggering the unit... sorta : ) The points never wear out since the triggering signal is only about two hundred and fifty milliamps (a quarter of an amp) as compared to 10 or 11 amps in the stock system. But the rubbing block wears down and you have to regap the points every 25000 miles or so. And as the miles build up the spring on the points weakens and you start to see points bounce, even at fairly low speeds. But points are inexpensive, robust and universally available making their use practical. I started using CDI modules in the 1960's and used the stock points for triggering until something better came along.
As a final note, a lotta guys go to a CDI module because they are having ignition problems and sure enough, the problem goes away once the unit is installed. You'll hear this same story from guys who merely replace their points with a Pertronix or other brand of electronic switch. But the odds are, the problem would have gone away with a good tune-up or rebuilding the distributor, which needs its seals replaced about every 50000 to 70000 miles. If your distributor needs an overhaul, the mainshaft will be loose and that looseness will cause excessive 'hunting' -- the spark won't always occur at the proper time.
A CDI module will trigger reliably with a point gap that's too small to measure (!), meaning it will even trigger reliably (although not accurately) with a distributor that is virtually worn out. By the same token, replacing the points with some form of magnetic triggering often masks that wear. Your distributor is still worn out and should be overhauled or replaced but the 'hunting' will have vanished... right up until the mainshaft binds or the dog gear breaks off or some other catastropic failure occurs.
There's no such thing as a free lunch : )
 

 

CDI Installation

 

Question -
Soon our Bug is going to have a silver finned box mounted on the fan housing to boost the voltage in the ignition system. The instructions say to mount it as close to the coil as possible -- is it OK to drill a couple of holes in the fan housing and mount it with the sheet metal screws that are provided?)
Rob responded -
You could put it on the fan shroud -- it wouldn't worry the shroud at all, but that means it will be subject to engine vibration. Another good place is on the left side of the firewall, near where the wiring harness comes into the engine bay. This has two advantages, it gets less vibration, and it's in the path of cooling air being sucked into the fan through the grills above. You just need self tapping screws long enough to penetrate the firewall padding, but not so long they poke through the carpet/felt on the inside.
That means the finning will get some useful airflow over them. It DOES run hot it's the nature of the beast. That's what finally killed mine off several of the components slowly cooked themselves, and it wasn't worth fixing it up. My version had a plain box (no fins) with the power transistors mounted to the box itself. They were OK, but several components inside the box cooked. Hopefully the improved layout of commercial units like yours, with the finned box, will stand up better. Had I known I might have tried putting air holes in the side of the box.
 

CDI Installation Procedure


1. Locate a location for the CDI unit as close to the coil as possible (e.g., firewall. The fan housing may not be a good location because of vibration).
NOTE: The firewall is ribbed for strength, so you might find some screws go in further than the others before touching the firewall.
2. Mount the CDI unit with metal screws supplied in the kit. Use toothed lock washers under the screw heads to assure a ground connection. Alternately, run a 14 gauge wire from one of the CDI mount screws to a body bolt.
3. Disconnect all wires from the negative (-) side of the coil.
4. Remove connectors from the wires removed from the negative side of the coil. Twist all of these wires together and attach them to a female terminal connector.
5. Connect the black wire on the CDI to the negative terminal on the coil.
6. Connect the green wire on the CDI to the green distributor wire.
7. Remove all wires from the positive (+) side of the coil.
8. Removed connectors from the wires removed from the positive side of the coil. Twist all of these wires together and attach them to a female terminal connector.
9. Connect the CDI white wire to the positive side of the coil.
10. Slip vinyl tubing from the kit onto the CDI red wire. Connect the red wire to the ignition wire removed from the positive side of the coil. Move the vinyl tubing to cover the terminal.

 

CDI Wiring

Wire

Connections

Red

Ignition switch, automatic choke, electro cutoff valve, backup lights

Green

Green wire from the distributor

Black

Negative coil terminal (#1)

White

Positive coil terminal (#15)

Electronic Ignition

Material gleaned from various VW newsgroup conversations and direct e-mail correspondence.
Advice from John Connolly (Aircooled.Net) -
Replace your points and condenser with electronic ignition (e.g., Pertronix or Compufire) Takes only 20 minutes to install. Contrary to popular "wisdom", you are not going to get a huge power increase with this part. You WILL get a no-maintenance item (unless you love adjusting points and timing), which gives rock-steady ignition timing under all conditions. In my opinion, this is a must-do modification even for stock cars! Getting the rubber grommet into the hole properly is the hardest part of the job (I'm not kidding).
The Wisdom Bob Hoover regarding Electronic Ignition -
If you want to make it last forever, or at least longer than the 70,000 or so it normally lasts, get rid of the points. Opening the points represents as asymmetric load on the distributor. Opening the points is the major cause for wear on the shaft and bushings. So get rid of them. Use a Pertronix unit. No load on the distributor shaft. Runs concentrically. Vastly reduces the wear-rate which is already pretty low because the distributor only turns at one-half engine speed. (Don't use an optically triggered unit. The Pertronix is magnetic.)
Buy a Pertronix 'Ignitor' that fits your distributor. Pull the distributor and install the 'Ignitor'. Be careful of the wiring. One lead is +12v, the other is the signal lead... it goes to the coil's negative terminal. The ground is internal through the body of the distributor.
Be sure to set the proper air gap and make sure the Hall effect sensor (the black epoxy cube on the aluminum plate) is standing square to the plate. I've installed several of these and most were bent right out of the box due to improper riveting. Easy enough to straighten but if you don't notice it the thing can actually rub against the magnet ring... not a good idea. (And yes, it's 'magnet' not 'magnetic'. There are four high-strength magnets cast into the nylon (?) ring that fits down over the cam lobes of the distributor shaft.)
Make sure the magnet ring is pressed FULLY down onto the cam lobes. There are instructions with the Ignitor but the illustrations don't look much like the real thing.
Put the rotor back on. (You can expect to wear out a rotor about every two years due to the higher spark voltage. Just carry a spare so it won't leave you stranded. Ditto for the cap.) Make sure the ROTOR seats fully. On some distributors, you can't use the 'Ignitor' because the magnet ring prevents the rotor from seating full depth. (But you can machine a bit off the lower edge of the rotor, if you're careful doing it.)
Fire it up. Hey! Now THAT's a difference. Reason is,you've just eliminated a lot of mechanical jitter that is present in most old distributors. The jitter is still there but the triggering method used by the 'Ignitor' masks it. No more points bounce. In fact, no more points, period. Your plugs are now being fired in response to an electronic signal that is far, far more precise than any mechanical switching arrangement.
Slap a strobe on that puppy. And plug a sniffer up the tail pipe -- you can lean that thing down by quite a bit, now that you've got a higher spark voltage. Static timing okay? Then go ahead and kick it up to where the advance is all in and check the max. Dial it back down to thirty degrees or less. (I run 28. Yeah, I know. But I'm more concerned with getting there than how fast I can get there.) Hot weather, bad gas, heavy load, crank it back a bit more. And tweak your idle down better ignition has caused your idle rpm to increase. Keep them between 800 and 900 rpm. Any slower and the engine won't cool properly when you come off the freeway, etc.
Now here's what's gonna happen. Your mileage is going to take a nice jump. Most folks report an improvement of 8 to 15 percent. Depending on how much you drive, that alone will pay for the mods in about two years. But the driving! Damn! The thing really DOES run better! That's because you've gotten rid of points-bounce and shaft-jitter and incomplete combustion at higher rpms. And that means your engine will last a little longer because your oil is going to stay a little cleaner because there won't be so many unburned hydrocarbons in the blow-by that gets into the crankcase.
Plus it's going to start better. A LOT better. And no more cross firing during damp weather. And your engine is running cooler, too! Those Corvair-type air seals really make a difference.
I've been using such an ignition system for nearly thirty years -- it's been available that long. I first wrote about it on the internet more than five years ago... and immediately got a blizzard of flamers and hate mail -- lots of kiddies shouting 'If it's really that good and really that easy, then why haven't we seen anything about it in the magazines?'
Question -
Today a friend suggested installing electronic ignition. Have you had any experience with this? Might it be a good thing to do?
Jim Mais ("Speedy Jim") responded -
Electronic ignition is nice ... but ... it's not a panacea. The stock ignition should make that engine run just fine. First find out why it doesn't run right.
Question -
I was wondering what models people had luck with. I stray away from Pertronix because they have had so many warranty claims.
Response -
I've had great luck with the Pertronix. I think the warranty claims were mostly because the unit was a bit too big for the 009 distributors, and didn't fit right. It wasn't possible to create a gap, it rubbed. They've fixed that, and now it fits fine. The unit itself works fine. I have one in my '70 Ghia, and I've driven it for 6 months that way, with zero problems. I also talked to a lot of people before buying it, particularly shops that sold both units (Compufire and Pertronix). The unanimous opinion was Pertronix.
Question -
Pertronix is a primary improvement, and only removes tuning up the points/condenser. The other performance is the same.
Bob Hoover responded -
The above isn't entirely true. The points represent an asymmetric load on the distributor shaft. With mechanical points that asymmetry leads to some degree of "hunting" at low speeds.
At higher speeds the inertia of the system tends to damp-out the hunting, but, depending on the age of your points and the amount of wear in the system, you begin to experience some degree of points-bounce.
The Pertronix units I've bought and tested eliminated both of these problems. The net effect is a more stable, more uniform ignition at all engine speeds and some small improvement in fuel economy because of it.
Question -
The next investment that I'm considering is a Pertronix system. I hear Bob Hoover and others talking about how this will save you from having to fuss with the points, but is there a clear advantage performance-wise?
Response -
Nope. The hotter spark of the CDI gives you better performance, but the Pertronix simply replaces the points with an electronic trigger for the CDI. So it will stay timed longer need almost no adjustment, as it has no rubbing/wearing parts.
The only performance advantage would be staying in tune. I guess that if the engine was running at high revs a lot you'd also have the advantage of no "points float" which tends to upset the timing a little, but since you car is not a racer I doubt you'd notice ANY difference in performance. I'm certainly not knocking them, I'd be quite happy to try it out just don't see the need if you are happy to check the timing regularly.
Question -
While my car runs very well I would prefer it was stock. Do you have any experience or knowledge about this subject and also do you have any experience with the Petronix Ignitor pointless system?
Response -
Petronix - I haven't used one my self, but I know how they work. You replace the points with the sensor (and you usually need a new resistor-less rotor arm too) and the sensor provides the trigger for the normal coil. So you get normal spark voltages, but no wearing of points and usually less "shake" in the timing, since it's only distributor driveshaft wear which could now cause "shake" and not the points cam and jumping points too. Since there are no points to wear, the timing doesn't alter and you have less tuning to do.

             Ignition Questions and Answers

Dave confessed to a mistake -
I accidentally attached the wire from the ignition switch to the wrong side of the coil.
Rob offered the following advice -
Probably blown the condenser. My guess is the coil will have survived. If you have a multimeter, you can test the primary 12 volt circuit (the and + connections). Zero resistance means it's blown any resistance means the circuit is still intact. the secondary (high voltage) circuit will be OK it's unlikely to be affected by a blown primary circuit, so you won't need to check this (if you want to, you check between the centre electrode and earth and you'll need to use a high resistance scale I forget the range it should be in, but much higher than the primary.
Also have a look at the little (should be black) wire on the points this might have melted. Also check the fuses quite possibly blown one of these too.
Also check the wiring to the idle cut off and choke -- cross wiring might have cooked these.
Condenser, the points wire in the dizzy, and the fuse are the most likely damaged parts.
One easy check (so you don't "shock" yourself with the main coil wire), is to use a spare plug on any of the plug leads and rest the plug on some exposed metal, such as against the inlet manifold near the plug holes. You should get a spark, and it's easy to see if it's in the shadow down there.
John Connolly (Aircooled.Net)offered the following advice -
Replace the ignition cap and rotor: three minutes (give or take). Bosch is the ONLY brand of these parts that I recommend you install. Leave the clear distributor caps for the show cars (they run like crap). Make sure you switch wires one at a time!!
Question -
I am searching for an answer to my ignition problem. I have power going to my coil but it is not making it to the plugs. I have replaced the rotor, points and condenser. Is their any other checks I can do on the condenser or something else?
Response -
Disconnect one side of the coil (either one) and put an ohm meter across the primary terminal ( + and -). You should get 3-4 ohms. If it's either high or no resistance, the primary coil is shot and you'll get no sparks from that coil.
If the resistance is OK, then he could try wiring a spare plug to the centre wire, resting it on the case and turning the ignition. Should get a nice stream of sparks at the plug (all four cylinders worth). If not, then the problem is in the secondary (high voltage) winding of the coil. Replacement coil should fix either of these problems.
Question -
I read in a Clymer Manual that I could have shorted out my distributor, does that mean the points and condenser? I assume so -- I don't really know. The term "shorted out" would obviously refer to the electrical components -- I'll bet they're talking about the cap.
Response -
The only way of "shorting the distributor" is to put the wires incorrectly on the coil - reversing the + and - connections so the current is flowing the wrong way through the points. This can blow the condenser, and may cause pitting or burning of the points (obvious to look at).
Question -
I have an old distributor with the single vacuum line and one wire coming out from the condenser. I didn't want to change it out for a newer one.
Dave's impetuous response -
Absolutely not! This is a Single Vacuum Dual Advance (SVDA) distributor, the best match for the 30 and 34 PICT carburetors. Don't let someone try to talk you into a 009 centrifugal advance distributor!
Rob's calmer voice -
You may be talking about some later VW distributors with a different condenser arrangement. Some use the canister as one side of the circuit - so it's firmly attached to the distributor body. Some use a "two wire" condenser and that has to have one wire attached to the condenser and the other to the coil (as normal). Electrically, either will work.

 

Tune-up Procedures

Written for Dave's 1973 VW Super Beetle, but will apply to any aircooled Volkswagen
~~~
Step 1. Compression Test
1. Start the engine and warm it up for about 10 minutes.
2. Pull the spark plug connectors off all four plugs (careful--the engine is hot!)
3. Inspect the wires and the rubber seals on the ends. If worn or defective, replace them.
4. Stow the wires so you'll know what goes where.
Note: A handy trick is to wrap thin strands of copper wire around both ends of the spark plug wires--one loop for Cylinder #1, two loops for Cylinder #2, and so on. This way there is no question about which wire goes where. Refer to the diagram at the beginning of the Valve Adjustment procedure to see which cylinder is which and where the firing point for each is on the distributor.
5. With the spark plug socket on the ratchet, loosen all four plugs until they're hand tight. Use the extension and socket to screw out the last few threads by hand.
6. Lay the spark plugs out in a pattern to match the way they came out of the engine. You will carefully inspect and gap the plugs in the next step.
7. Check the compression with the compression tester:
o Hold the rubber end of the tester in the spark plug hole, tightly.
o Have a buddy turn the engine over six times and record the data.
o The test results should be over 100 pounds and within about five pounds of each other.
o Low readings indicate need for an engine overhaul.
8. Since you have the spark plugs out, proceed to Step #2, "Inspect, Adjust and Install Spark Plugs."
 

Step 2. Inspect, Adjust and Install Spark Plugs
1. Pull the spark plug connectors off all four spark plugs.
2. Inspect the wires and the rubber seals on the ends. If worn or defective, replace them. The large rubber seals around the spark plug leads are important - they seal the cooling air in around the heads, and MUST be replaced if they won't stay snuggly against the hole in the tinware.
3. Stow the wires so you'll know what goes where.
Note: A handy trick is to wrap thin strands of copper wire around both ends of the spark plug wires--one loop for Cylinder #1, two loops for Cylinder #2, and so on. This way there is no question about which wire goes where. Refer to the diagram at the beginning of the Valve Adjustment procedure to see which cylinder is which and where the firing point for each is on the distributor.
4. With the spark plug socket on the 3/8" drive ratchet, loosen all four plugs until they're hand tight. Use the extension and socket to screw out the last few threads by hand.
NOTE: It's best to wait until the engine is cold before removing the spark plugs. If you try to remove them from a hot engine, you run the risk of galling the threads. Bob Hoover has strong feelings about this -- "This is the standard rule for aluminum heads, and has been since the 1920's. The world is filled with engines having aluminum heads, but about the only folks who seem to have trouble with stripped spark plug holes are kids with Volkswagens. I wonder why that is..."
5. Lay the spark plugs out in a pattern to match the way they came out of the engine.

6. If you are going to reuse the plugs, inspect them carefully, comparing them to the pictures in the Bentley manual. If necessary, clean the plugs or install new ones.
7. Set the gap between the bottom bent electrode and the center straight electrode to 0.028" using the feeler gauge on the gapping tool. The bent electrode can be carefully bent in and out with the gapping tool to make the adjustment.
NOTE: If you have a capacitive discharge ignition (CDI) system installed in your car, the spark plugs should be gapped to 0.040".
8. Make sure there is a gasket on each plug, then put the plug in the spark plug socket.
NOTE: If the plug is very tight in the socket, you will have a very difficult time getting the socket off of the plug once the plug is installed. To prevent lots of frustration, apply some silicone grease to the plug before putting it in the socket; this will make removal of the socket much easier. Be sure to wipe the grease off the end of the plug before installing the spark plug wire.
9. Put the plug in the cylinder that it came from and hand tighten with the extension (do all four). Put on the ratchet and tighten them all--fairly tight but don't overdo it (snug and a tug). The cylinder heads are soft aluminum, so be careful you don't cross thread the plugs - they should start in the holes and turn fairly easily just using your hand. Torque the plugs to 22 ft-lb with the engine no more than warm.
A very pertinent note from our friend Bob Hoover: "Be damn sure to use a dab of anti-sieze on the threads of the plugs and that the compression washer is in place. Install the plugs BY HAND until the thread is full depth. Don't put a wrench on the plugs until they are fully threaded into their bores. And if you can't thread them in by hand, you've got galled threads and need to do something about it -- it ain't gonna heal itself."

10. Put the plug wires on the same way you took them off. Make sure the rubber seals are pushed down firmly on the spark plugs and that the rubber seal is seated properly in the hole in the tin.



 

 

 

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Last modified: February 11, 2007