Rotor-Type Oil Pump: Many engines are equipped with rotor type oil pump. It has a central rotor with outer lobes which continuously rotates inside the outer ring having internal lobes.

The fin­ished powerplant is much more like a set of siamese twins than a single 4-Rotor engine. They share a common oil pump, submerged in a single sump, and a com­mon water pump, but each has ...