An apparatus to transfer power from rotary power to reciprocating power includes an odd numbered multi-lobed rotating cam that acts on a follower, which, in turn, causes or acts in response to reciprocation of pistons. The follower includes offset head portions and the cylinders, in turn are actually offset in the direction of the head portions. This reduces friction and improves efficiency. Further, the cylinders can include two inlets and two outlets so that each cylinder functions when the piston moves in either direction within the cylinder.