Engine balance

[Steve Daniel (37270)]

What is the difference between internally and externaly balanced ?

Steve

[Joe Lucia (12484)]

Re: Engine balance

Steve-----

In an internally balanced engine all of the engine balancing is done through balance of the internal reciprocating assembly. Usually, this involves the configuration and balancing of the crankshaft.

In an externally balanced engine, the flywheel and/or harmonic balancer are counterweighted to achieve complete balance of the engine. Usually, this is done because the internal crankshaft counterweights needed to balance a particular engine configuration would need to be too large to be practical. The only alternative would be the addition of heavy metal to the crankshaft counterweights and this is usually too expensive for PRODUCTION purposes.

The only Chevrolet engines that are externally balanced are the 454 and 502 big blocks and the 400 small block and some later 350 small blocks. An externally balanced engine can be converted to an internally balanced by balancing with the addition of heavy metal to the crankshaft. The New GM 496 cid engine used in truck and marine applications, which is basically a stroked 454, is a PRODUCTION internally balanced engine.