I have a vibration that occurs while that car is stationary, with the clutch in or out. It is first noticable at 1100 RPM and starts to taper off above 4000 RPM. Initially, I thought that the engine was the problem, like a balancing problem or an off-center clutch. However, while reving the engine with my head under the hood the enigne seems not to vibrate at all. It feels as though the engine is simply resonating through the body.

Prior to the T-56 swap I had some vibration. The motor mounts are so stiff that the engine doesn't move even when you hammer the throttle and I think that this has something to do with it.

Since the swap though, the vibration is more pronounced - like right up my butt! The T-5 had a rubber isolator to dampen vibration. The Spohn cross member has only 1/8 of rubber strip between the cross member and the body (presumably for ground clearance reasons).

Again, this is RPM related and not related to speed. I haven't tried to spin the engine on its own to prove that this is not related to the flywheel, clutch or transmission input shaft. I was just wondering if there was anyone else with a similar issue and set of circumstances?

Thanks,
Jon

JSD MOD 27/05/09

 

While you say it's not engine related, if it happens with the clutch in, car stationary, RPM dependent, it's most definitely engine related... Nothing else would be moving/rotating in the drivetrain past the flywheel, so you should still be looking at an engine/flywheel vibration issue.

 

Yeah, I'll have to bite the bullet and take down the transmission again (that sucker's heavy!) and see what happens when the engine turns all on its own.
Thanks,
Jon

 

Just thought I'd update this thread.

First off, I'd originally posted that the Spohn cross member doesn't have a rubber isolator between it and the transmission. I'm a moron, it does.

I removed the transmission and clutch and ran the engine. No vibration! I'd read a post or two where guys had repositioned their torque converters to solve vibration issues. So, before removing the clutch I indexed it to the flywheel. When we reinsatalled it we rotated the clutch to the next bolt position. There was definitely some vibration but it was less than before (although without the transmission etc. to transmit the vibration though the body it would seem less). We tried with and without the clutch disc installed - no difference. So now I was thinking that perhaps the pressure plate was unbalanced.

The next step was to rotate the clutch again so that it was 180* from where we started. I was expecting this to yield the best result but ran into an electrical issue and couldn't start the car. In frustration, we put the clutch back 90* from the index mark (since I thought it seemed a little better) and put it all back together. The end result? No change at all. Argggh!

So this week, it all comes apart again with a spare clutch on hand and we'll see....