wilkinstan

A few months ago I had a shop in Nevada replace the balance and timing belts on my 86 951 as I don't have a garage right now. After this the belt whine from under the hood has sounded as if I am driving a belt driven supercharger under there. (think Mad Max ) The shop told me that it is normal and the belts will just have to stretch out a bit. After 1500 miles on them the whine has decreased slightly but is still pretty loud. I think they overtightened the belts. I dont know if this kind of whine is normal for new belts as I have never heard the car with new belts but the car has never sounded like this before . Any Ideas would be helpful. Thanks.

schwank

Welcome to the club. Some of the sound can be tuned out but you'll find that is a common 'issue' for these cars. It can be the result of belt tension or the position of the idler pulleys. My car made that noise all year last year... through 12 track days. I retensioned so many times and it wouldn't go away.

The belts should be retensioned after about 1500 miles though regardless.

JET951

i would not say its an issue, people dont know what the tension is meant to be and they tighten the balance belt the same tension(or close to) as the cam belt. the balance belt has very little tension and the idle pully barely touches the balance belt. if done correctly there will be very little whine if any at all.
Sean

nick_968

Sounds like your balance belt is over tightened. It should be about twice as loose as your cam belt as it goes round twice as fast. Get this right and the whine will go away.

wilkinstan

Thanks for the good information. I'll check the balance belt. - Stan

968turbos2

+1 What Jet951 said. The balance shaft belt has alot les tension than cam belt.

xsboost90

Mine almost always whine. Only time i had one that didnt whine alittle was when i put all new rollers on it. Usually if i back it off enough that it stops whining then its too loose.

eniac

I get the same thing and without belt covers it's very noticable. I would rather live with the whine than see the belt flapping around. I have tried retensioning many times. Also have tried with the tensioners and idle pulley in various positions with little improvement. Guess I'll just have to add a supercharger one of these days.

hansman

I dont know if this helps but I have noticed on several occasions that with a cheaper set of "timing belt kits" I come up with a noticable difference in belt noise.

dhall615

the wine i have from the belts comes from my alternator belt. see if that is the problem

DDP

It's suppose to be that loose. It looks scary, but just know that the whine is not the correct tension.

eniac

If I put my belt covers back on I'd have no problem running them that loose.
My tension is just slightly more then it should be. I don't see any harm this would cause. I have thought of installing another idle pulley somehow but the whine isn't bad enough to warrant that much work.