Abstract: A photo electric ignition system for an internal combustion engine is described which comprises a timing housing having an orifice on its upper surface admitting light beams from a radiant energy source.A light sensing photo electric cell is operated by an input frequency control rotor. The rotary member comprising a cone shaped rotor having an open end chamber with angularly spaced apart apertures extending there into. The rotor is mounted on a driving shaft which is connected to a crankshaft in the engine block. The open end chamber being rotated adjacent the orifice on the surface of the timer allows alternate focusing and blocking of light beams from radiant energy source on the photo cell so to operate the cell a number of degrees in synchronism with the engine rotations.The phased interval signal provided by the photo cell is transmitted to an amplifier which is interconnected to an ignition coil providing high voltage firings for the spark plugs in the engine cylinders.