Good inputs here guys. I would like to maintain the internal balance.
Question about the balancing of the rotating assembly. Is the crank the only part dynamically balanced and the rods and pistons just weighed and made all the same?
Yes, that is correct. Note however, the rods are weighed on both ends and fussed with until all weigh the same on both ends. Then a bobweight can be calculated and added to the throws on the crank for the dynamic crank balance procedure.