What are the symptoms of a broken balance shaft belt?

[SpicyOrange]

My 95 GS-t has developed a high Rpm vibration that shakes the entire car upon acceleration. I also notice that it vibrates violently when I downshift into 3rd gear on the freeway and the rpms rise. Is it possible that BS belt has snapped and would cause this?

Thanks

Nick

[Goat Blower]

Sure sounds like it.

[Raptor]

Sounds like it and I wouldn't drive it till I knew for sure. Don't want to lose the timing belt as well.

[john]

I had a broken b-shaft belt after a bad install but it didn't seem to run any different. I didn't loose the t-belt. Luckly I swapped the t-belt at 20K as another bad install (wrong bolts in the oil pan) wore a a groove in the timing belt. I would pull off the timing cover for sure though. Defintly cannot hurt anything. Vibration could also be caused by a bad motor mount.

[Raptor]

If the bearing on the rear balance shaft went, it could make some pretty nasty vibrations as well, should hear that pretty well if it were the case though.

[SpicyOrange]

Thanks guys. I'm gonna tear it apart tonight after work.... I forgot to mention that I just got it running and was breaking the clutch in and the Timing belt was next on my list of shit to do since the previous owner never replaced it and the car has 109k on it. So I sure hope that is my vibration, other wise I am stumped.

[SpicyOrange]

If the bearing on the rear balance shaft went, it could make some pretty nasty vibrations as well, should hear that pretty well if it were the case though.
So tell me more about this bearing? Is it common for it to go out? Is there any diagnosis to see if it is bad?

I did the Timing belt and balance shaft belt tonight and once I had it apart I knew it wasn't gonna fix anything. The motor has a pretty bad shake at idle, and you can feel it get noticably worse at 3500 rpms. I almost positive its in the motor. Pushing the clutch in has not affect on the vibration. It will vibrate while the car is standing still or moving at 60mph. Please help!

Nick

[john]

2600 clutch?

[SpicyOrange]

Spec stage 1

[Raptor]

Check the oil for bearing material. The balance shaft that is driven off the oil pump has a bearing that fails on the end opposite the pump fairly often. I have seen several this year, that can cause it to shake, but there is also usually a noise associated with it as well. As far as checking it, pulling the pan is the best way to know for sure that it is bad or not. Half the time it fails you will find a mangled bearing in the pan.

The one thing that hasn't been brought up in this thread and should is that the obvious things are often overlooked. Don't make the mistake of pinning this on something severe until you know the car has no other more simple issues that can cause this as well. Make sure it is firing on all the cylinders etc. A bad plug wire or plug can cause the exact same vibrations you are talking about. Listening to the engine would obviously help us to trouble shoot the problem and on that note, if you are anywhere near the shop, maybe I can come over quick and give you a better idea whats up. If thats the case, give me a call.