A mechanical engine cylinder system, includes a cylinder, an occupying structure with a cavity, and a crankshaft piston, the cylinder having a dedicated compression space and a dedicated combustion space, the occupying structure having a primary combustion space utilized during an early stage of a power stroke, wherein combustion pressure applied to the crankshaft piston during the power stroke is applied to a smaller surface area of the crankshaft piston during an early stage of the power stroke and to a larger surface area of the crankshaft piston during a later stage of the power stroke, the combustion pressure applied to the occupying structure applies a net-force to the occupying structure in the direction of the crankshaft piston during the early stage of the power stroke, and in the opposite direction of the crankshaft piston during the later stage of the power stroke.