Quote:

Reciprocating weight comes to a dead stop @ TDC & BDC. Zero. Not moving. It doesn't carry over anything.
It requires power to stop it, and power to start it. All of these are completely wasted when the direction changes.

The only stored inertial energy is rotational.



that's why if your planning on using a lightened crankshaft, you should plan on lighter reciprocating parts too. less wasted energy.

machine shop owner and engine builder