Abstract: A hydraulic engine having a frame on which a crankshaft is rotatably mounted between a plurality of cylinders. The individual cylinders are rockingly mounted on the frame arranged as opposed pairs of cylinders and their piston rods are operatively connected to cranks positioned 90.degree. apart upon the crankshaft. A power take-off shaft is also journalled on the frame and a drive train operatively connects the crankshaft to the power take-off shaft. The cylinders are connected by a fluid circuit to a motor-driven pump and included in the circuit are individual distribution valves for the cylinders. Operating plungers of the valves are connected by rods to eccentrics carried by the crankshaft and circumferentially positioned to extend and retract the several piston rods in a sequence which will rotate the crankshaft and deliver usable power to the takeoff shaft.