Thread: 383 Shaking Like H@[[,3000 To 4000.why!!

Tweet

Originally Posted by SMOKEDOG7142000

JUST ONE TIME I WOULD LIKE TO COME ON HERE WITHOUT A PROBLEM! HERES WHATS WRONG,IM HOPING SOMEONE CAN HELP.FINISHED BUILDING A 383 STROKER.THERE IS PROBABLY 2 HOURS ON THE ENGINE,GIVE OR TAKE 5 MINUTES EITHER WAY.JUST STARTED TO SHAKE PRETTY VIOLENTLY BETWEEN 3 AND 4 THOUSAND.I DISCONECTED ALL THE BELT DRIVEN PARTS,STEERING PUMP,ALTERNATOR,AND WATER PUMP,TO SEE IF THIS WAS WERE THE PROBLEM WAS.NO. IT DONT MATTER IF ITS IN GEAR OR OUT,NOR DOES IT MATTER IF ITS UNDER HEAVY OR LIGHT THROTTLE. THERE IS NOTHING VISIBLE THAT WOULD LOOK LIKE THE PROBLEM.ALSO,THE ENGINE IS NOT MAKING ANY UNUSUAL SOUNDS OR NOISES. GUYS,IM STUMPED!!! COULD IT BE THE HARMONIC BALANCER,I PUT A NEW ONE ON AT REBUILD,IT IS A STOCK 400 8 INCH REPLACEMENT.I ALSO PUT IN AN SFI RATED FLEXPLATE[FLYWHEEL].???????HELP!!! THANKS IN ADVANCE!!!

Is this an int. balance engine or an ext. balance engine?

Originally Posted by erik erikson

Is this an int. balance engine or an ext. balance engine?

that was my point he not sure he did not build it or balance it he has no way of knowing

With what he is experiencing I'd bet it's externally balanced.
When I put a stock 400 in a '62 pickup I first hung a 283 flywheel on the end of it. To say that it shook is an understatement. I only drove it around the block and in that short amount of time it wiped out the rear main seal and I was told that there was a great possibility of breaking the crank. I solved the problem with a 454 flywheel.