my 383 was just finished yesterday, fired it up broke in the cam and then noticed that the crank was vibrating badly. the eagle rotating kit was internally ballanced, (saw the drilled holes), and my flywheel and balancer are both for internally balanced. i thought if i got a motor built with everything brand new i wouldnt have problems anymore, but i guess not.

 

What do you mean by "any more"? Was there a vibration problem with a previous motor? If so, and it's now happening to your totally different/new motor I would start thinking about what you swapped over from engine to engine that might be causing a vibration- balancer, flexplate/flywheel, and don't forget about front end accessories- they spin, too.

 

for some reason i thought i remembered somebody saying that the other motor had vibrations too, but i meant all random problems. but the only things i reused was a water pump and flywheel with 800 miles on it. the water pump pulley seemed to be a little bent before, but i replaced that. would a water pump cause bad enough vibrations to be able to cause damage? also is there any way that a harmonic balancer would ever go bad, or cause it to come out of balance?

 

Take the fan belts off and run it for a little to check the accessories.
Harmonic balancers certainly do go bad (even explode sometimes).
A new one is only $69.
If the vibration is still there without the accessories running and a new balancer installed, it's either the rotating assy or the flywheel/clutch cover.
Flywheel/clutch vibration will be felt in the drivers seat more than the floorboard in neutral. Rotating assy vibration will be felt more in the floorboard under the pedals.

 

well, i would check into that, but i called summit the other day and found out that they sent me an external balanced kit, so i ordered a flywheel and balancer.
that really pissed me off cause i was on the phone with a guy from summit when i ordered the kit and i told him that i needed internally. but atleast this problem is solved. thanks for the help.