Abstract: An eccentric ring porting system for hydraulic pumps of the type having a rotating cylinder block. The rotating cylinder block has a flat annular port face with a small cluster of regularly spaced cylinder ports in the face circularly arrayed about the axis of rotation of the cylinder block. A ring valve element has a ring seat surface held flush against the cylinder port face. The axis of the ring seat surface is eccentrically offset from the axis of rotation of the cylinder block, and the cylinder ports are uncovered inside of the inner edge of the ring seat surface for output porting of the pump and outside of the outer edge of the ring seat surface for inlet porting of the pump.