rotational axis c and the center of the valve stem 21 so that the contact point a is on the center of the shim 23 and accordingly there will be no lift because there will in essence be no significant pivotal movement of the rocker arms 32 that is the rocker arm 32 may pivot slightly but this will merely result in sliding movement of the valve actuating or contacting section 34 of the rocker arm across the valve shim 23 without its opening because of this operation the engine 11 can be operated without any throttle valves in the induction system the engine speed can be controlled by varying the valve lift to control the induction air flow thus simplifying the engine construction and improving transient response thus from the foregoing description it should be readily apparent that the described embodiment of the invention provides a very wide range of valve lift adjustments without unduly complicated physical structure and without otherwise jeopardizing the valve actuation in fact this mechanism also reduces the necessity for subsequent valve adjustment due to wear since wear will be minimized this mechanism also permits reduction in hydrocarbon emissions particularly during engine starting and even may eliminate the utilization of a throttle valve is used in conjunction with the intake valves because they can be retained from opening in the foregoing description it has been disclosed that the variable valve lift mechanisms are all operated simultaneously of course it would be possible to actuate them each independently the invention has also been described in conjunction with an arrangement wherein the valve stem axis intersects the camshaft rotational axis but that need not be the case various other changes and.