Abstract: An inventive internal combustion engine adapted for an eight piston stroke operating cycle. The rate of comsumption of fuel and air mixture, and the pressure at which it is ignited and combusted, is enhanced by the addition of a holding chamber for fuel and air mixture which retains an initial intake charge of mixture to be later mixed with a subsequent intake charge before compression and combustion within the cylinder. The engine is therefore capable of greater power with given size cylinders. Conversely, the engine is capable of producing a target rate of fuel consumption and power output with smaller cylinders. The engine may also be designed to operate in a Diesel manner utilizing an appropriate hydrocarbon fuel.