NotDads442

1967 400: After a long mechanical restoration I have a terrible engine vibration from about 3k-5200k. Does it with the car in neutral sitting there and brought up to 3k. I bought the Mahle pistons from Mark Remmel on here and the rotating assembly was balanced locally. I own a shop and we found it odd that the machine shop asked for everything including the clutch disc, which changes position every time the clutch is used. I sent the balancer to Damper Doctor in CA during restoration and it was balanced with the crank, rods, etc. I installed new motor mounts and transmission mount during the restoration. I can't help but think the engine is out of balance.

Another question I have is if you balance a flywheel and the day comes you need a new one, does this necessitate removing the engine and tearing it all down to be re-balanced again?

It pains me to think this would need to be all torn down again.

cutlassefi

If they balanced it with the balancer and flywheel/flexplate, that should be fine. The only other variable would be the pressure plate, not the clutch disc.
They should’ve had to remove a fair amount of weight from the Crank to make it right with those Pistons. Ask for the balance sheet and see what they have on there.
Hope this helps.

NotDads442

There are not too many shops in the Spokane Coeur d’Alene area who balance. I’ll call the machine shop Monday, they sublet this part out. I remember my machinist saying though they had a hard time with it and had to take a bunch out because of those lightweight pistons.

are you saying we are dealing with a clutch pressure plate issue?

cutlassefi

Maybe, but it’s way easier to take weight out than add it. Not sure why that posed a problem, it shouldn’t have.

dragline

Broken motor mount?

NotDads442

I pulled the trans, bell and clutch last night. Came off with a broken ear on the Muncie. The paint marks from the balancing shop were lined up between the pressure plate and the flywheel. I do have some abonormal heat marks on the flywheel. I did when I tore the car down too. My foreman said at the time that the old style paddle clutches were not his favorite to see and that whoever it put that clutch in did not turn the flywheel. I have a flywheel machine and we turned it before it went out for balancing.

Thinking of supporting the engine and starting it with the clutch off and seeing if it is still out of balance. Thoughts on this?

RandyS

Is there a bearing or bushing in the end of the crank to accept the input shaft of the tranny? In normal use, an ear should never break off of a tranny case.

NotDads442

yes we have a pilot bearing.

cjsdad

Just a weak stab in the dark, did you run the firing order the right way round the distributor? Not sure the engine would even run if you did it the wrong way round. Like I said, just a weak stab...

NotDads442

I pulled the trans, bell and pressure plate and we ran it on the hoist and the vibration is still there. The balance was sublet, I am on the phone now with that company. S & J engines Spokane....

RandyS

Another shot in the dark..... does the motor run smoothly at idle? (thinking possible plug wire problem - switched, not on tight)