Abstract: A method is described wherein the efficiency of an internal combustion engine is upgraded. Heat from the engine block is used to generate high pressure steam. The steam is generated in a chamber separate from and in addition to the standard engine cooling system water jacket. The high pressure steam is fed to a selected one of the engine pistons and used to drive that piston in an otherwise alternating pattern with the combustion stroke. The steam drive and the combustion drive for the selected piston alternate one with respect to the other.