Abstract: A combined oil pump and balance module for mounting in an oil sump of a reciprocating piston engine includes a housing supporting a rotatable balance shaft carrying at opposite ends balance weights for offsetting unbalance forces of the engine. The balance weights are enclosed in open top enclosures from which oil is pumped by vanes on the weights and an associated gear, driven by the engine crankshaft. A pair of oil pumps are mounted on opposite ends of the housing inboard of the weights. The pumps draw oil from the sump through housing passages and deliver the oil to one or more engine oil systems. In one embodiment, the first pump feeds oil to a lubrication system and to the second pump, which delivers oil at a higher pressure to a hydraulic actuating system of the engine.