Consider a symmetrical two cylinder V-engine, as shown in Fig.12.35. The common crank OC is driven by two connecting rods PC and QC. The lines of stroke OP and OQ are inclined to the vertical OY, at an angle α.

Fig.12.35 Balancing of V-engines

Inertia force due to the reciprocating parts of cylinder 1, along the line of stroke

Inertia force due to the reciprocating parts of cylinder 2, along the line of stroke