I'm trying to track down a vibration at 3000. It does it in all gears. I dont remember if it does it in neutral or not.

Engine was just rebuilt (150 miles so far), flywheel resurfaced, and new clutch (CF DF).

Is it possible that the engine is at fault b/c it wasn't "balanced" by the builder?

I'm leaning toward the flywheel - should it have been balanced after the resurface job? Can this type of clutch be balanced?

The car didn't vibrate b4 the rebuild.

Whats the best way to approach this?

Thanks
Vince

One more thing to add...the vibration is pretty signifigant.

Vince

Vince,
You did not say exactly what was done on the rebuild. If the pistons were changed, and the new ones are significantly lighter or heavier, then it is possible that is causing the vibration. We just got a set of the "new" Sealed Power/Speed Pro/TRW forged pistons to replace a set in a 396 and they are significantly heavier than the old ones. I had to add about 70 grams of weight to the crankshaft to balance it.
Resurfacing the flywheel, if done properly, should not affect the balance much, if at all. I have had several customers lately with vibration problems with CF pressure plates. You cannot balance them, they are done from the factory. The first thing I would try, and its a pain, would be to take the trans out, remove the pressure plate and try running the engine without the pressure plate on it. If the vibration is gone, you found your problem.
Hope this helps,

Hi Bill,

Yes, the engine was rebuilt w/Speed-Pro's forged units. I'm a little dissapointed quite frankly with my builder for other items, so this wouldn't suprise me.

I'll start by pulling the trans 1st. I cant really enjoy this motor w/the vibration - 3000rpm is a much-used rpm range for me.

Vince

Before you remove the pressure plate mark how it is installed. If it is not the engine you may want to try reinstalling 180 degrees from your marks. I had a vibration in a small block after changing the clutch and it went away by doing this.

One other suggestion is to make sure you use shouldered bolts to attach the pressure plate. If you just use regular grade 8 bolts the pressure plate can shift and be off by .050 which is a good deal with the weight of the CF DF plate.

Along the lines of what "Yellow" said, did your flywheel have metal dowels to locate the PP and were they 'reinstalled' after resurfacing?

Along the lines of what "Yellow" said, did your flywheel have metal dowels to locate the PP and were they 'reinstalled' after resurfacing? What dowels? I did use new Mr. Gasket pressure plate bolts that have the shoulder on them.

Vince

just a thought. you didnt by chance change the harmonic balancer after rebuilding and maybe put one for a 454 on it?

my engine is ext balanced(400) but I had a brand new harm. balancer (500 miles) go bad on me, outer ring slipped and it caused me a bunch of grief trying to figure out why the motor was shaking