Roral

I just spent the weekend doing the belts on my car, with Lizard from the 928 board. It went very well.

I just have some questions for any one who has had their belts done recently. I am more then likely just scared to drive the car hard right now. But i notice a belt or roller noise i am guess the belts/rollers just need to be broken in. How long should i be expecting these noises to happen for?

Also ever since i have done the belts, in second gear at 2900-3000rpm it gets a little vibration you can feel through the whole car, along with a total power loss some times from start, in first gear around 1100-1200rpm as if it has actually stalled, yet it still accels. Any ideas out there i'll give it a try.

Thanks, Steve

Dilberto

No, belt whine should not be increasingly louder, as the revs go up. This means the idler rollers are screaming for relief. Their sole function is to prevent belt distortion, when downshifting/decelerating. When the car is off and the engine COLD, the balance shaft belt should rest .028" from the idler. The idler should rarely spin- only in the occasion the belt deflection makes the belt touch the idler. Position and lock the idler away from the traveling belt by the specified amount(.028). Use a feeler guage to verify.

Peckster

The vibration is new? Sounds like you installed your balance belt out of sync by 180 degrees. Happens a lot.

peterjcb

What Peckster said above. Check out Clark's Garage Tutorial for Balance Belt installations
I just recently did mine found the information there very helpful.

Roral

Well I know what the car runs like when there is no balance shafts at all, the belt broke, and i didn't know. Infact i think the PO of this car knew it had snapped and thats why he was looking to get rid of it in such a hurry. And it was rough at idle thought i did not know if it was really rough or just the natural feeling for the car since i have only been in 3 944's; now however the car runs smooth, actually it runs like a new car, except for those in those two gears. Maybe it's just me looking for things that could be wrong.
This weekend i'll lighten the tension on the idle roller, if i still have any whine i'll post with more info.

Thanks guys, Steve

hosrom_951

Balance shaft belt is too tight

The DareDevil

something is too tight!

threesticks1

If the balance shaft belt is just a little too tight you will hear a whine. Try re-tensioning both of the belts.

The local mechanic also pointed out the the new belts that they have been getting from their supplier seem to have more of a texture on the wear surfaces of the balance belt and seems to be causing more noise.

Macfreak007

one thing to look at on the balance shaft belt to tell how tight it is is does it make a straight line from that bottom gear to the top one? must come off the side of the gear almost making a 90 degree angle and the hit the other at the same point. Kinda of hard to understand on the web much easier in real life. But the balance shaft belt is much looser than anyone ever thinks.

hosrom_951

Yes, the Balance shaft belt