Engine Vibration :(((

[E30M30]

Hi

I've spent all vinter building a pontiac 455 engine. I used a re-ground crank, srp-pistons and scat rods. I've also installed a new balancer. I had the engine dynoed and it made 450 hp and 575 torque - so far so good. The dyno shop said the engine ran good and strong. The problem is, that I'm having some nasty vibration from 1800 rpm and up. No matter if I have the clutch depressed or not, and the car being stationary or moving. What should I do? I've replaced the starter ring gear - should I have the flywheel balanced?? Or do I have to tear down the engine completely again and have balancer/crank/rods/pistons/flywheel and clutch balanced (right in the middle of the driving season.....) Are some of the pontiac engines externally balanced ? (no weights on my flywheel) But I don't know about the engine, from where I got my crank. Sorry about my scandinavian/english ;)))

[Pro Stock]

I suggest that you contact Jim Butler at Jim Butler Performance, he should be able to help you. By the way, your English and writing skills are better than most U.S. citizens.


www.jbp-pontiac.com/

Dale

[chevybuldr]

Did you have the crank balanced to begine with? Will the flywheel bolt holes only like up with the crank one way? If you had the assembly balanced did you get the pressure plate balanced and did you line it up the way they did?

[E30M30]

Flywheel could be mounted in several locations. I didn't have anything balanced.....

Dale - I'll contact Jim and thanks ;)

[Roadrage David]

Dale for a good european sirves contact http://www.centralvirginiamachine.com/ Builder of the fastest pontiac engine till date!!!!
and one of the most hounest man you wil ever deal with!

[chevybuldr]

The problem is, none of those parts that you bought are close to factory weight stuff. You need to have it balanced.
I also might be wrong but I think that flywheel has weight on it. Wether its more holes on one side or less holes, not sure. I could be wrong. You need to balance the assembly though.

[Exiled]

[QUOTE=E30M30;537496]Flywheel could be mounted in several locations. I didn't have anything balanced.....

The flywheel should only fit in one position. The bolt holes are not the same distance apart for this resone. If its not in the right position yo cant get all the bolts started & if its in the right position all the bolts fit.

[Exiled]

Pontiacs are internally balanced. If you didn’t get anything balanced then that’s going to be the problem. The only time you may get by without balancing is if your just re-ring & bearing the motor. Then the stock or previous balance “could” work fine.

As chevybuldr posted, all your parts are nowhere near the weights of your prior parts.

Id go with the builders that Pro Stock & David mentioned

[E30M30]

I'm tearing out the engine this thursday.... Well I'll know what to do, the next time I'm building an engine.. Thanks for your help guys!!