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914World.com _ 914World Garage _ Six cylinder fan belts

Posted by: Eddie914 Sep 22 2005, 12:44 PM

So all six cylinder Porsche engines use the same fan belt?

A long time Porsche owner told me that all six cylinder Porsche engines use the same fan belt. He gave me a replacement belt from his '79 3.0 to use on my '77 2.7. Even with no shims between the pulley halves, the belt did not seem tight enough.

Any input appreciated.

Thanks

Eddie

Posted by: ArtechnikA Sep 22 2005, 12:50 PM

i counted at least 4 different sizes on the Pelican site...

a 2,7 should have a 10x710

(an early 3,0 uses a 10x725...)

Posted by: Kerrys914 Sep 22 2005, 12:52 PM

Not sure if they are the same BUT I do know you need to use all washers/shims. IIRC you need to have 6 ? total. If you have none between the pulleys then you would have all 6 outside under the nut. Without them the nut will not tighten up correctly.

The fan belt looked to be a standard fan belt such that and FLAPS could find a replacement in various lengths.

Cheers

Posted by: Eddie914 Sep 22 2005, 01:24 PM

All the washers are on the outside of the pulley and the nut is snug. I'm have to check, but I'm guessing that I was given the 10x725 size belt when the 10x710 was the size needed.

The alternator light never came on but the belt may have been slipping only at high RPMs. The oil temperature was never above 210 after the through the hood oil cooler ducting was installed, but that does not mean that the head temperatures did not see elevated temps due to a slipping belt. It could have contributed to the dropped valve (and ensuing carnage). I'm fairly sure that the badly worn exhaust guides were the major factor in the failure of the valve.

Eddie

Posted by: goose2 Sep 22 2005, 03:26 PM

There are several different size belts because over the years, Porsche tried different size pulleys to vary the fan drive ratio.

Posted by: ArtechnikA Sep 22 2005, 03:31 PM

QUOTE (goose2 @ Sep 22 2005, 05:26 PM)
...over the years, Porsche tried different size pulleys to vary the fan drive ratio.

that's true, but as long as the sum of the circumfrences is the same, and the mounting centerlines are the same, the belt length remains the same.

IOW - there are fewer belts than there are combinations of pulley sizes.

my quick glance indicated they were all pretty much the same up to the 3,0.