Abstract: A revolving cylinder engine having a stationary fixed housing with circumferential intake and exhaust ports and an ignition means, a concentrically positioned revolving cylinder block bored centrally and radially with said radial bore defining a piston compression chamber, and a crank bearing disc concentrically positioned within said central bore of said cylinder block that revolves within said cylinder block wherein the rotation of said crank bearing disc provides for the reciprocating action of the piston traveling through said compression chamber. A planetary gearset is the preferable means for rotating said cylinder block and said crank bearing disc for achieving the timing requirements necessary for precise port alignment in concert with the movement and position of said piston.