Abstract: A rotary-piston internal combustion engine having one or any number of rotary pistons, mounted in a cylindrical cylinder block, the cylinder block being mounted for rotation in an elliptical casing, on a central hub associated with said casing. A central drive shaft is connected to the cylinder block for rotation therewith, and each cylinder provides one power stroke per revolution of the cylinder block. Each cylinder is provided with a push rod, adapted to be restrained against the interior of the cylindrical wall of the engine casing. The engine is self-lubricating, and eliminates the need for a crankshaft, has a minimum of moving parts and thus friction points are minimal provides a hugh power-to-weight ratio and minimizes exhaust emissions. Ignition may be either by spark means, or by dieseling.