Alternator/Fan Belt Too Big?

[porschedude996]

I bought a Continental Belt from our host (10 x 710) and have only run it a couple hours. I am still in the process to get the engine to pass emissions testing. I just placed the only washer that was on the inside of the pulley to the outside and still the belt slips when I try to rotate the engine. Has anyone had this issue?

I think I'll try the Porsche Branded Belt.

[David Inc.]

Does it slip all of the time or just part of the time when you're rotating the fan? Mine slips on the compression stroke when I'm turning it by hand but if I put a bit of pressure on the slack side of the belt with my hand it will grip and turn the crank.

[OldSpool87]

When I did my valve lash about a year ago, I had to put a little inward pressure on the belt with my finger while I rotated the fan pulley to get the crank pulley to move. Not a ton of pressure, just a bit of deflection.

[smadsen]

So many of these cars have been backdated & forward dated with parts changed around you never know if you have the proper pulley pieces or belt. The 10x710 belt is correct for the SC's and I'd start with three washers on each side. I'm not sure what a 996 calls for.

A picture or two of the pulleys & the make & model engine might help those more knowledgeable than me to identify the problem.

[porschedude996]

Originally Posted by smadsen

So many of these cars have been backdated & forward dated with parts changed around you never know if you have the proper pulley pieces or belt. The 10x710 belt is correct for the SC's and I'd start with three washers on each side. I'm not sure what a 996 calls for.

A picture or two of the pulleys & the make & model engine might help those more knowledgeable than me to identify the problem.

I did give that a thought, but the car is so original.

When I first installed, the washer count was one on the inside, and five on the nut side.

I did put some pressure on the trailing side and got a bit of traction. But, given the initial single washer with a new belt, something is wrong.

Another thought was worn pulley halves. But that doesn’t appear to be so.

My lower pulley has both grooves (Fan & Air-Con Pump). That rules out early OEM pulley swap. I think i’ll try a factory belt.

Thanks all for the inputs!

[GH85Carrera]

I tried several aftermarket belts, and the ONLY one that fit right was the Porsche branded belt. The others were just close enough to work, but never fit right. Order the Porsche branded one. You will be happier with the fitment. Pelican sells them or go to a local dealer and have them get it for you.

Put the Continental belt in the trunk as a spare for emergency use.

[76FJ55]

What year car are you working on? I'm assuming it isn't a 996 as referenced in you user name.

[88911coupe]

I don't think the 996 uses the same "system" for the belt as the air cooled cars.

[TeeJayHoward]

There's also the 695 belt, if the 710 is obviously too loose.

[porschedude996]

Originally Posted by GH85Carrera

I tried several aftermarket belts, and the ONLY one that fit right was the Porsche branded belt. The others were just close enough to work, but never fit right. Order the Porsche branded one. You will be happier with the fitment. Pelican sells them or go to a local dealer and have them get it for you.

Put the Continental belt in the trunk as a spare for emergency use.

I have two Porsche belts on order. I think the best place for the Chinese Continental belt is in my 55 gal receptacle that’s picked up weekly.

I’ve changed several cars since my 996TT. I went with something much simpler. I am working on my 1983 SC.

Thanks for all the comments.

[porschedude996]

Originally Posted by TeeJayHoward

There's also the 695 belt, if the 710 is obviously too loose.

Huh, I never saw the 695 reference until you brought it up. I looked at the OEM Parts manual and there is three sizes. 695, 710, and 725. I bet the 695 is my answer. i’m

[TeeJayHoward]

Originally Posted by porschedude996

Huh, I never saw the 695 reference until you brought it up. I looked at the OEM Parts manual and there is three sizes. 695, 710, and 725. I bet the 695 is my answer.

Be careful. You CAN fit a 695 belt on a 710 setup, and it will stress the alternator shaft and wear it prematurely. It's cheap enough to be worth trying, just be aware - If a 695 feels too tight with the shims all set inside, it's probably the wrong belt.

[porschedude996]

Originally Posted by TeeJayHoward

Be careful. You CAN fit a 695 belt on a 710 setup, and it will stress the alternator shaft and wear it prematurely. It's cheap enough to be worth trying, just be aware - If a 695 feels too tight with the shims all set inside, it's probably the wrong belt.

Good to know, thanks. My target is 3 and 3 shims.