Good Vibrations? (1 Viewer)

[Mr 40]

Maybe not,`79 fj-40 ,305 sbc has low to mid rpm range vibration.I replaced motor mounts and no difference.This is in neutral and stopped.It clears up as the rpm`s increase.Any ideas ???? Thanks Guys...

 

[Sharp38]

Assuming a standard transmission, being in neutral, you have eliminated everything from the output shaft of the transmission back. Does anything change when you push in the clutch?

It may not actually being "going away" when you increase RPM, it may just be you can't feel it anymore due to the frequency of the vibration.

This could be:
1. Loose Harmonic balancer
2. Misfire on one cylinder (Ignition/Injector)
3. Clutch/Flywheel

Don

 

[Mr 40]

No change when i push in the clutch,thanks for your reply .I will check the thing you suggested.

 

[Fast Eddy]

Maybe the rotating assembly was balanced at one time, then someone replaced the clutch and put the flywheel back rotated?

 

[Sharp38]

Mr 40. Did you build this engine or have it built? Do you know it's history. I am assuming your 305 has a one piece rear main seal. If so, the flywheel, balancer are different than with the older type engines. Is it a possibility that someone mixed up some of those components?

Is everything on your flywheel/clutch nice and tight, bolts to crankshaft, bolts from pressure plate to flywheel?

Don

 

[Mr 40]

I bought this with engine already installed,ran the block # on GM site and it `s a 1980-1984 305 truck engine .Also can`t really see clutch/flywheel because it has an adapter with no access as far as I can tell ?? Thanks for the ideas