I have a pretty bad vibration at mid-high RPM that is definitely engine related. I have had others look at the car and is seems that everyone agrees that something is terribly out of balance.

Any opinion as to what it is? Damper? Flywheel? Internals? I'm hoping damper...easiest to replace...this needs to be fixed so I don't blow the engine apart.

 

How did you determine it's engine related?

 

Increases with higher RPM, entire car shakes, two mechanics have told me they thought it was a damper or flywheel. Happens whether the car's in neutral or not...can't be driveshaft related. What else could it be?

 

Did you check the motor mounts?

 

Just a visual inspection...look fine. Is there any other warning signs for mounts?

 

Has the engine had work done to it? If so what was the last thing done? Is it a stick or an automatic? Is it a small block or a big block? What size? Is it externally or internally balanced? If it is an auto, did you disconnect the converter from the flexplate and try it? I may have some more suggestions with some more info. Good luck

Russ

 

Its a 3970010 block from a 1975 truck. It could be a 2 bolt or 4 bolt...they used both. No idea on internals but it was "rebuilt," whatever that could mean. The last owner used this block with the original L82 heads, original carb, etc. Beyond that, I don't know much about the engine itself. Oh, its a 350 (may be a 355 with overbore, not sure).

The car is a 4-speed. The only work I have done to the trans is replacing the mount and getting the speedo in working order...and a fluid change. Its a 3.70 rear end.

Hope that helps some...

Thanks

 

Any other ideas on what this could be? We're supposed to have 60 degrees this weekend, I may have an itch to work on the car a little

 

check the harmonic balancer to be sure it has not separated or partially separated from the hub.

one way to check engine mounts: while in car with one foot on gas and one foot on brake, give it a little gas without letting car roll. with the hood open and a friend looking in the engine bay, he/she should see the engine stay in place. if it moves very much, the mount could be broken, you'll know. and also, don't run over your friend!

 

And which foot does he put on the clutch

 

Binnie77: And which foot does he put on the clutch
Answer: was multi-tasking, thanks

well forget that test - unless you have an emergency brake that really works. i kinda doubt it's the mounts anyway.

i've had pilot bearings go bad in those rpm ranges, but i would describe them as a high frequency very noisy vibration. either they make the noise or don't (when they began going bad). couldn't get the vibration with the car parked in neutral, but could with the clutch pedal depressed.

 

Its a 1973...I have an e-brake but it does not work. I doubt it EVER worked. E-brake is on my list but not yet fixed