I have a vortec motor, m-21 w/ 11" ram clutch, and a lakewood scattershield. The vibration is worse between 55 and 70. It is not too bad at 72, but if I push in the clutch and release it sometimes it will be alot worse and if I push in the clutch and release it, it will go back to not being so bad. Any suggestions?

And the vibration is worse at part throttle and it is also more cyclical.

Mike

[ 04-04-2004, 08:18 PM: Message edited by: michwalt15 ]

I'd say either the input shaft pilot bushing or the M-21 input bearing.

I rebuilt the transmission a few months ago along with the pilot bushing, mainshaft, u-joints, motor mount, trans. mount, pinion yoke, trans. yoke, tailshaft and bushing, and the entire rear-end.
Sorry this was probably info you could have used.
graemlins/clonk.gif

Did you use one of those needle bearing pilot bushings? Also, was the flywheel balanced to your engine?

If your flywheel or pressure plate is off balance, and your disc is also off balance, the unbalanced forces can cancel each other out sometimes, depending on what position the disc is in when the pressure plate clamps down on it. A local clutch & driveshaft guy told me he has seen so much radial runout on clutch discs in the past few years that he checks every one that comes into his shop. My '72 Nova has a similar problem.

I asked the guys at Napa if they could balance the flywheel and clutch, but he said that since it was a vortec motor it had to be balanced with the entire rotating assembly. If this is the case is there a better/easier way to balance them? Would a higher quality clutch help, perhaps a centerforce?

And no I am using the pilot bushing not a bearing. The last pilot bearing I used got chewed up.

Thanks
Mike

Sounds (reads) like a trip to the dealer for replacement parts. Or, take the clutch parts to an engine balancer have them neutral balance it.