Rudeboy,

The photo you sent illustrates Mallory metal (I believe it is either a Tungsten, Osmium, Iridium, or Uranium alloy) slugs, embedded into a balancer plate.

They may better balance the engine than solely the crankshaft counterweight, but they have little effect, if any, on what I illustrated in my message.

To come to a real balance, you would need two such balancer plates; each with one quarter of the needed, full counterweight; one on the front of the crankshaft (around the propeller end) and one on its rear end, both geared to rotate at crankshaft speed and both in opposite rotation to the crankshaft, which has half the needed, full counterweight.

The gearing must put all three counterweights down at the same time and up at the same time, but fully counteracting to the left and to the right. When the crankshaft counterweight is on the left, the balancer plates' counterweights are both on the right and vice-versa.

This way, the reciprocating mass is fully balanced up-and-down. Only much lighter second order vibrations, remain unbalanced. And at the same time, no left-to-right vibrations result, because the crankshaft and the two balancer plates counteract each other laterally.

Sincerely,