I recently built a new engine and had the bottom end balanced. I put a new center force clutch on this engine. The balancer had the flywheel but not the clutch asm. The problem is that I have a vibration from 2200 to 3600 rpm's. I'm told this means it's in the flywheel or clutch cover. I found out recently that there are supposed to be marks on them to index them. I got a new GM performance parts flywheel and centerforce II and I don't remember any marks but I don't remember looking for them either. Is some of the balance weight in the clutch cover? If not what is the difference how it goes on. I hope someone has an answer, I don't want to pull the engine again.

 

The best way to balance a motor is to neutral-balance the engine, such that no special flywheel is required to "match" to it. For that reason, I always make it a point to NEVER supply the flywheel, clutch, or other parts to be balanced along with an engine. I have the engine properly balanced, then the other parts balanced individually; that way they retain their interchangeability.

Clutch covers are supposed to be neutral-balanced. There are no marks on them from the factory. They should be able to go on the flywheel in any orientation.

Flywheels have a dowel pin hole, and cranks also have one; although there's no dowel pin (usually). If you're working on a 86-up 1-piece rear main seal engine, there is a small amount of balancing weight added to the flywheel, and the flywheel must therefore be put on the engine in the correct orientation.

Did you use real clutch bolts, or some other bolts you got from somewhere?