[gtofreek]

Originally Posted by pontibeast

Paul I am new to this level of engine's. What does neutral balancing mean? I have seen cranks that have been balanced, both drilled and with Mallory metal having to be added but I have never been taught what that term means. Thanks

Cranks are either internally[neutral] balanced, or externally balanced. What that means is that an externally balanced engine uses a counterweight on the flexplate/flywheel, or the balancer, or both. They use this counterweight to help balance the crankshaft. They go to counterweighted flexplates/flywheels, and balancers when there is not enough counterweight on the crank to internally[neutral] balance it. Pontiac had enough room to make the front counterweight big enough, but because of block configuration, they couldn't put a big enough counterweight on the rear, so they counterweighted the flexplate/flywheel only. So on a Pontiac, only the rear is externally balanced. Most externally balanced engines have counterweights on both the balancer, and the flexplate/flywheel. By going to lighter weight rods, and pistons, I was able to neutral balance the rear. Now I can neutral balance his flexplate. Pontiac flexplates did not have a counterweight welded to them like most counterweighted flexplates. Instead, Pontiac drilled four big holes on one side of the flexplate.

The problem with externally balanced engines is even though the crank is technically balanced, the flexplate/flywheel, and balancer are still have a counterweight on them that is pulling on the part, much like the moon pulls on the earth when it rotates. This counterweight, when spinning at several thousand rpm's, is trying to pull on the flexplate as it spins. External balancing is not really good for a performance engine. Performance engines are much better off if they are neutral balanced.

Mallory, or heavy metal is used to internally[or neutral] balance cranks. It weighs a little more than twice what steel weighs.