Abstract: An engine in which a very lean mixture of fuel and air can be compressed, ignited and burned to completion outside of the cylinders of an internal combustion engine before it is introduced into a cylinder for effecting a power stroke. Two pistons operate together, piston one being for suction and piston two for power. Piston one introduces and compresses the fuel into rotating combution chambers, and piston two receives the burned fuel and air mixture to produce the power stroke. As the combustion chambers rotate, the fuel and air mixture is ignited by a glow plug. After ignition, the ignited fuel remains confined within the rotating combustion chambers to assure complete combustion. The expanded fuel powers the piston in the second cylinder and is then discharged as a clean exhaust.