Lighter pistons...rebalancing?

daredevil said

lighter is better on rebalancing price as you drill the crank counterweights instead of adding Mallory metal which is expensive. Lil cuda i could see that in a horizontally opposed motor but why do you balance cranks in 6s? Horizontally opposed i could see how the crank would weigh the same on both sides. why does the crank have counterweights? Not saying youre wrong just need a little explanation so i understand. i,m not a machinist so i like to know why things work.

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In a straight or horizontally opposed 4 or 6, they always have the same number of pistons "up" as they do "down" at any given time. The crank counterweights are there to balance the crank itself.

In a v engine (4, 6 or 8 ), the counterweights have to counterbalance the crank, big end of the rods and a part of the reciprocating weight (which includes the pistons, pins, wrist pin clips, and the small end of the rod) also. Therefore, they must be balanced when the pistons change weight significantly.