Engine vibration

Anyone ever had a harmonic vibration and find a fix for it?

I have one that comes in and out at about 2,000 to 2,200 rpm's. I have replaced the vibration damper 2X. I also have tried re-indexing the torque converter 180 then 90 degrees. I have also unhooked all the drive belts-no change. It does it at idle or when driving at the same rpm's. I do notice if someone is riding with me it is not as bad. 72 351C 4V with C6.

Any suggestions??

TFA

Maybe put a dial indicator on the flex plate to see if it is warped?

David

Inspect the flex-plate and converter for missing balance weights.

Paul

Inspect the flex-plate and converter for missing balance weights.

Paul

Click to expand...

...or cracks

Also, sometimes a miss presents as a vibration.

Did you run the engine with the converter off. That would exclude the trany. Did you run it with all the belts off? I have the same problem but my car is in paint and I can't address it until it gets back. Maybe looses up all the mounts one at a time and rock the engine and trans a couple of times and retighten.

If your using 50oz flexplate it sure will vibrate, don't ask me how I know

Inspect the flex-plate and converter for missing balance weights.

Paul

Click to expand...

...or cracks

Also, sometimes a miss presents as a vibration.

Click to expand...

+1 on the miss. We did all the troubleshooting you are going through. Ours was found to be a combination of vacuum setup + an irregularity in the coil / distributor output. PM me if you want more info on what we found/ did to solve.

Butch

Inspect the flex-plate and converter for missing balance weights.

Paul

Click to expand...

...or cracks

Also, sometimes a miss presents as a vibration.

Click to expand...

+1 on the miss. We did all the troubleshooting you are going through. Ours was found to be a combination of vacuum setup + an irregularity in the coil / distributor output. PM me if you want more info on what we found/ did to solve.

Butch

Click to expand...

TFA,

Sorry to hijack your thread.

Butch,

I will be hitting you up. I noticed when I put my car on the trailer right before paint that putting the air filter seem to lessen the vibration.

I went thru the same problem. try balancing the drive shaft. remove axles and have machinist spin on a lathe to check straightness. check pinion angle. make sure the rubber in the transmission mount is not collapsed otherwise you will have metal to metal contact under trans.

Inspect the flex-plate and converter for missing balance weights.

Paul

Click to expand...

...or cracks

Also, sometimes a miss presents as a vibration.

Click to expand...

+1 on the miss. We did all the troubleshooting you are going through. Ours was found to be a combination of vacuum setup + an irregularity in the coil / distributor output. PM me if you want more info on what we found/ did to solve.

Butch

Click to expand...

Yeah interested what you found.

Not sure how to PM you.

TFA

Click on his user name and select "PM User"

Paul