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When an engine produces more power, it subsequently produces more heat. This means that cooling is more important now than before. This guy always fits a new thermostat to a performance engine, as the cost far out weighs the trouble caused if it doesn't work. Another favorite of this guy is the Cylinder Cool Tin, these are a copy of the Type 3 under cylinder deflector. They cause the air coming down from the fan housing to wrap around the lower part of the cylinder far better than those tiny little plates you have already. Never run an engine without a thermostat and the associated flaps. People say things like, "the daily temperature here is over 100*F", ok, but the operating temperature of your engine is about 80*C.
You should also use a cylinder head temperature gauge and connect it to cylinder #3 (as this is always the hottest). The senders for these gauges fit under the spark plug like a washer, but be careful as they are easy to break. I have, in the past, connected them to a cylinder head bolt, the upper one second in from the left on the left hand head, but this does mean drilling the tinware and more importantly, they are there to stay once the tinware has been fitted.
If you have fitted an external oil cooler you can change your fan housing for one other than a "dog-house" type (that's the standard type used after 1971). You must remove the control flaps from within your old fan housing and transfer them to the new aftermarket one you have bought. The reason for this is that those flaps allow the engine to reach its correct operating temperature quite quickly and thereby reduce cylinder wear to a minimum. Be aware that many of the aftermarket fan housings don't fit too well and do not have provision for the control flaps, if this is the case, don't buy it. You really can't do much better than the standard post 1971 fan housing, but remember if you are going to remove the oil cooler you will need to patch the back of the housing to keep the air in.
Power pulley are smaller pulley wheels which turn the fan slower and therefore require less power from the engine, that means the engine will not receive all the air it needs. It is worth noting that if you intend running your car in and around town, the power pulley is not for you, but if you plan on running your engine at high RPM for any length of time i.e. drag racing, you should consider one as the standard fan doesn't work very well over 6,000RPM (engine speed) and by reducing its speed it will extend the usable range of the fan. Please remember, if you use a power pulley in town, you are asking for trouble. There are also dry sump pump pulleys available, these are even smaller and have been designed to run with this huge pump. As this guy has already recommended you don't use a dry sump pump, you don't need to ask me about these pulleys.
My final point on cooling is this, Volkswagen spend a lot of time and money working out the best way to cool their engine, so what makes you think a badly fitting aluminum 36hp replica is going to work any better.



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Last modified: February 11, 2007