Help with Vibration
 

I just got my 924S back from the shop where I had among other things the timing/balance belts changed. I now have a vibration that increases with RPMs.

The mechanic is claiming that it is a bad flywheel, but the vib was not there before the belt change. I'm thinking the balance shafts were not aligned correctly.

In the words of Bill O'Riely, "What say you".

I imagine it is the timing belt. I do mine myself. Every now and then I'll misalign one - usually the lower one. It is not hard to do. There are marks on the plastic housing of the belt cover that should line up with a notch on each shaft drive pulley when the engine is at TDC.

Vibration is a high frequency one - twice engine speed.

I'm pretty sure Lawrence meant the balance belt. The shafts probably are not aligned correctly. Remove the belt cover(s) both upper and lower, set the engine to TDC and check the marks as suggested.

Yes, I did not type what I meant. It's the balance shaft belt. Sorry about that.

Where any front balance shaft seals replaced? if so, your mechanic may ahve gotten a pulley installed on the wrong keyslot.

No, no seals just the belts.

The mechanic is going to check balance shafts when it goes back tomorrow. I fragged the clutch this weekend.

You know I had her up to 130 mph and just knew she had 140 in her. Well she probably did but the rubber donut didn't. Ah well, I was wanting to put a spring centered clutch in anyway that donut had 100K miles on it.