By buzzy, I mean like Japanese 4-banger buzzy. Buzzy like a *****.

I thought of the heat shields, and don't think that's it. I was under the car while it was running this morning, and the noise is noticeable and sounds more like it's coming from something mechanical. It semed to be coming from either the clutch or motor. Then the cross over pipe got really hot and I got out from under there! From the driver's seat, it sounds like it could be a loose heat shield or something like that, but from under the car, no way.

So, I think you might have sorta said what I was hoping someone would say... if the pilot bearing was the problem, the noise would change when the clutch is engaged vs. disengaged! Time to get some sleep before someone disagrees!

 

When the balance shaft seals are replaced, could that throw off the balance shaft position? Are the balance shaft belts removed when the seals are replaced? I'm wondering if they could be off by a tooth or something... is this a reasonable thing that could have happened?

 

VT, it was nice to meet you at P2O. Sorry you are still having issues with your car.

The BS pulleys would come off when the seals are replaced. There is potential for them to be installed improperly, causing vibration. However, it would probably feel like a pretty heavy vibration and would not seem "buzzy". Have you ever heard a 944 with a balance belt improperly tensioned? It might almost sound like a "buzzing" sound or a "zing" or like a supercharger whine. I know I saw a red 944 this weekend that sounded like the BS belt was way too tight, but I honestly don't remember which one it was. I have also heard an intermittent harmonic sound when I was working on Gabe's timing belts. I'm pretty sure the root cause was having the cam belt slightly too snug, and improper torque on the cam belt tensioner stud. After some readjustment it went away.

If the problem was your pilot bearing, it would not start making the noise at all until the clutch pedal was depressed. The throwout bearing on the other hand has potential to make noise regardless of what you do with your left foot. If you determine that the problem is still clutch related I would plan on another tear down, but I bet you could milk it until winter. Catastrophic failure would be similar to the broken clutch fork. If the bearing were to totally sieze, it could potentially damage the pressure plate and fork. If it starts making awful noises, I would shut down. If not, I think you could proceed with caution.

Too bad you didn't mention your problem at oxford, I would have loved to go for a spin with you.

 

Ryan,

It was good to meet you, too. It might have been my car that you heard with the whining balance belts. The noise I'm worried about is in addition to the balance belt whine. The thing you mentioned about Gabe's car (intermittent harmonic sound) sounds about right. I guess I'll try to get the belts properly tentioned and hope that takes care of it. Thanks for you help!

Alan

 

Woohoo!!! Got the balance belt re-tensioned and the whining noise and "intermittent harmonic" noise and vibration are gone! I think it might have been either the belt vibrating (picture a guitar string) and maybe even running against the idler pulley.

THANKS EVERYONE for all the advice and help with all my stupid clutch questions! I hope this clutch lasts a really long time...

ADVICE for new 951 owners: take it easy on your clutch in 1st and 2nd gears and don't floor it until your foot is off the clutch pedal! As many have mentioned here, the clutches in these cars don't like hard launches. I think my autocross driving habits (hard launches and hard 1-2 and 2-1 shifts) probably hurried the clutch fork failure along.

 

Glad its fixed!

 

congrats!

 

Too early in the morning for my tired brain, but how the hell did you get your car onto those stands anyway?? I can't figure it out??

 

yeah the balance belt was set just a touch tight as im used to tensioning brand new belts that way. If thats the only problems we had after installing the turbo/motor and driving it in two days we did pretty good i'd say.