Abstract: A rotary motion device having piston valves that define an open region that are adapted to engage a power tooth of the power ring as the power ring rotates around the piston valves and the piston valves rotate about their own separate axis that is fixed with respect to the base housing of the device. The power ring is provided with radially inward and outward ports in one form that are adapted to communicate with radially inward and outward ports of a static member of the device. The ports are utilized to compress and expand a gas and in one form are utilized for an internal combustion chamber to create an internal combustion rotary motion device.