future

I have just changed all my belts on my 951 with the much appreciated help of 'Charlotte944' but am now experiencing load wining noises and I can’t figure out what’s causing it.

I only replaced the belts as all the pulleys looked and turned smoothly and the water pump had no play in it. The belts are all tensioned correctly and I thought a first that the noise could be due to the cam belt maybe rubbing on the plastic cover.

I loosened the belts and moved them so they were central on all the pulleys so what could it be or is it possible that this noise will disappear after time.

I’m going to put the car up on a ramp and use a stethoscope against the plastic cover to see if I can locate the sound, but until then does anybody have any other suggestions?

There was no noise present before I replaced the belts.

P.S. Thanks again 'Charlotte944' – You are the BELT MASTER!!! I felt well chuffed after doing the job and would recommend everybody do this job themselves as its not as difficult as it looks if you take your time. I recon the next time I do it, it will probably only take me 3hrs max.

One last thing. I cleaned all the parts that I removed in a chemical parts cleaner machine and sandblasted all the alloy parts during doing the job and now when I rev the engine the engine takes time to settle down what could be causing this?

GOD I LOVE RENNLIST – and my 951

Musche

I have the same problem although it has quieted down a little bit since the new belts were installed. It will be interesting to hear the expert opinions!

OriginalSterm

my rollers looked fine, but when pulled from the car the bearings were shot. and when i replaced those, my whining noise went away.

Bill

It has been my experience that a belt will "whine" when it is over-tensioned. A pulley that is seizing can also "whine".

Did you check to see that all the rollers spun freely? Did you use a belt gauge to tension?

There are two different tensions given in the factory manual. One setting for a new belt and one for a used belt. The new belt setting is tighter, as a new belt will stretch. This is why you must retension 1,500 miles after a new belt is installed. If you used the new belt tension for a used belt, it will be too tight.

Also equally important to the belt gauge is that the engine must be dead cold prior to tensioning. Aluminum expands at twice the rate of cast iron. Our engine grows when it gets hot. Even an engine that has set for 2-4 hours can be warm enough to affect tension. But a belt tensioned on a warm engine will be too loose.

cas951

Perfect answer Bill.

tjbreen

My car has had a whine since I got it. When I bought it, it had less than 10K on the belts, pullys, and water pump - all of which was installed at a Porsche dealer. I changed everything but the waterpump this March and had the belts professionally retensioned. It still makes the exact same sound. Must be the water pump.

ehall

Fellas, have you checked the AC/alt belt, and the v-belt for the p steering. They usually whine first. If you're hearing it from the timing belt cover, PULL OVER AND GET A TOW!

future

Bill... your advise is good and I have allready changed the tension several times using the tensioner tool set to new belt spec. I also tried the mechanics hand method as I know even many porsche dealer do (even though they don't tell us!!! and it still wined like my girl friend (she keeps saying when is the wedding to the car) as I spend more time in the garage than with her - She even told me one night that I should sleep with my car and locked me out of the house so I did - Those seats make for a good nights sleep

'Charlotte944' When I first fitted the belt I didn't tightern the alternator belt and power steering belts enough and they scream at me like my mum! so I tighterned them up and that solved the proplem.

I really think it is the waterpump, but why would it start doing it now when it did't do it before. If it's not that then I think it will be something to do with the balanceshaft belt.

Well it looks like it will be another night in the garage with Mrs to be 951

Musche

I noticed last night that the bushing/spacer that holds the alternator tensioner to the lower balance shaft cover appears to be on the wrong side making the tensioner look crooked. This could be causing the alternator to be off line with the belt and the source of my problem. I installed the a/c delete during the rebuild and probably screwed this up. I'll fix tonight and give an update.

future

OK I solved the problem...

Even though the balance sheft belt was tensioned correctly I have loosened it very slightly and the wining has almost gone.

I have to drive 250 miles tonight so when I get to my destination I'm going to retension the belt to factory spec.

It will be interesting to see if the belt make the same noise again after the long run and re-tensioning.

I'll keep you all posted.

Bill

Symptoms are symptoms. Belts whine, bearings whine. Rods knock, lifters clatter, exhaust leaks tick, etc. etc.

Like ehall correctly notes, there are other belts on our engine. My comment was "BELTS whine". All belts have a factory tension specification. All belts are meant to be set with the 9201 gauge.

You assure me that the belts were tensioned correctly, yet you have a whine. You "loosen the belt a little" and the whine goes away.

SET THE BELTS TO THE CORRECT FACTORY SPECIFICATION.

If a belt is too loose, it can slip and glaze. It can jump the pulleys. If a belt is too tight, it can stretch beyond the safe stretch limit. It will place undue side loading on bearings, which will whine and fail prematurely.

I made additonal comment on the timing belts, since you mentioned that you had just messed with them when the the whine appeared. Normal wear is a slow process. Whines, knocks, clatters start faint and grow. If something "just appears" it is usually from something that has been changed incorrectly.

Also something to keep in mind is the new belt break in period. Until a new belt stretches and then retensioned, it can whine. A faint whine is acceptable in this case. So you could be making something out of nothing. Or not.

Occationally I feel the need to state that trouble shooting over the internet is not the same as being there. Experience is no substitution for training. Internet recommendations are no substitution for experience. The nature of troubleshooting over the internet assumes that you have basic knowledge of mechanics. Replacing parts does not constitute the proper understanding of systems. Without proper understanding of cause and effect, you risk the continual replacement of parts.

If a recommendation is made for the sheep to be led to water, the sheep must take it upon themselves to not fall in and drown.

......and now I am done whining.