Fan drive belt tension

[John Clarke]

Hi All
With 356 fan drive belts of different lengths and adjustment at the generator pulley, does the fan drive speed vary much for cooling fan efficiency? Could you eliminate the shims from the inside of the pulley giving a faster fan speed and provide a belt tensioner roller/pulley between the crank pulley and genny?
Cheers Jay

[Wes Bender]

Eliminating the shims would bring the pulley halves closer together and would result in a larger fan pulley, thus slowing the fan down. You'd need to make the pulley smaller rather than larger.

Interesting concept on the belt tensioning idler though.

[John Clarke]

Hi Wes, You are correct, wrong way round! Add shims, for a smaller diameter driven pulley. i.e. faster fan speed.
Jay

[David Baugh]

Hi, John.

The VW guys have an idler pulley solution, very similar to what you have suggested. Don't know if it could be adapted to 356 use.

Dave

[David Jones]

Use a shorter fan belt and put in more shims thereby giving yourself a smaller pulley effectively.

[Geoff Fleming]

...and don't neglect to occasionally lubricate the fan belt with belt dressing. It adds life to it and prevents it from overheating and disintegrating.

[John Hearn]

Sorry to say this guys.
Keep it stock........why would you want to re-invent the wheel.
If you were racing the car on a circuit you would get a smaller pulley.
But then you would be changing many things, oil cooler for starters.
For the street leave it as the good Doctor made it............
KTF
John

[David Baugh]

Reading a bit of history, one learns that the good doctor welcomed innovation and improvements upon his designs.

Dave

[Wes Bender]

..an example of an improvement that Porsche should have incorporated in the first place is the full-flow oil filter. One can wonder how much money that little gem could have saved over the years.

[George Walling]

When dad and I were running VW Bugs and Buses we would run the smaller Porsche fan belt pulley. It helped for cooling in the hot weather as being smaller pulley it turns the fan faster and we never had a problem with gen or fan using the Porsche pulley. oh and we ran the stock VW crank pulley.
this also makes the air flow increase when wanting better heater and defrost. Never had a problem with it not warming up but we did run the cars with the stock engine heater flaps and bellow system.