Abstract: An internal combustion engine with a novel system of rotary valves is disclosed. A conventional engine has a pair of hollow tube rotary valves for each head, one tube being employed as an intake and the other tube as an exhaust. Slots are strategically placed around the circumference of each hollow tube. Each slot has a corresponding port located in the engine cylinder head and the slot passing over this port has a temperature and wear resistant seal that utilizes a wave spring (similar to an oil ring) to compensate for wear. The tubes are sealed on one end which is rotated from the crankshaft using a timing belt mechanism. The opposite end of each tube is fitted into a machined port in the cylinder head for conduction of gases. A carburetor or fuel/air control device is connected to the intake stationary port of the cylinder head. The exhaust system is connected directly to the cylinder port by the exhaust tube. The tubes are sealed to this stationary part with sealing rings.