Thread: Balancing and engine........needed???

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What all gets balanced?
I know on mine that they switched some of my rod numbers that I had stamped from place to place and ground on other rods. Weighed them with the pistons on. Line bored it also. I'm not sure what else got ground on. Probably the crank. I'm just curious what all gets balanced with an engine.

Essentially, everything that rotates. If an engine is internally balanced the flexplate (or flywheel) and damper are neutral, so they don't get balanced. If an engine is externally balanced those two parts must be done also. Some makes of engines come from the factory internal balance, and some are external balance, by design.

So, the crank, connecting rods, pistons, damper, and flexplate all get balanced. Pat , Jerry, and some others will know more, but my understanding is they find the lightest components and remove enough material from the others to make them all weigh the same, I think they also make the big ends of all the rods weigh the same, as well as the small ends all weighing the same. Then they do the pistons and pins. They will also remove material from the crank weights so that it spins with nothing out of balance.

The 350 Chevy engine I have in the shop was evidently balanced as I can see where material was removed from under each piston and also grind marks on the other parts. The idea is to make anything that rotates as close to perfect as possible to cut down on vibrations. I think the guy at the machine shop said something about him holding it to 1 gram, but I could be wrong on that.

If you can envision taking an electric fan and cutting a little off of one blade, how it would shake. By trimming all the blades exactly the same it would balance it, same thing they do iwth an engine. That is what little I know, or think I know, about engine balancing.

Don