Abstract: An internal combustion engine (10) with variable valve timing has one or more valve shafts (38, 44) connected to stepper motors (54) for angularly positioning the one or more valve shafts (38, 44) relative to an engine block (12). Flow passages (50, 52) are formed into the one or more valve shafts (38, 44) for passing intake air and exhaust gases into and from the engine (10). Sensors (58, 60 and 62) are located adjacent a crankshaft (28) and the one or more valve shafts (38, 44) for determining crankshaft positions and valve shaft positions relative to the engine block (12). An engine control unit (56) receives crank shaft and valve shaft position signals and emits control signals to the stepper motors (54) to selectively operate the engine in two stroke, four stroke, six stroke, eight stroke, and ten stroke modes.