Hello, is there a formula or technique to calculate the equivalent inertia of an engine? I think I will have to add up all the inertias of everything else rotating inside it but it has so many components like cams, followers, pulleys, water pump, crank, flywheel etc. What sort of effect will the reciprocating pistons have on the equivalent inertia? Is there no way of estimating a reasonable equivalent inertia of an engine without getting into all the complication of finding out the inertia for each and every rotating part? it does not have to be very accurate.