Abstract: A single stacked cam bearing surface is used to actuate several cam followers in such manner that the cam bearing surface can move past one or more cam followers without actuation thereof but can be caused to stop at and actuate any desired cam follower. A stacked disc cam bearing surface of the improved cam actuator assembly of the present invention includes rotatable cam sub-assembly discs each having a surface well. The plurality of cam followers that bear against the bearing surface are selectively actuated by a controlled positioning of the cam sub-assembly discs that radially aligns the wells of the bearing surface with a selected cam follower. During a controlled rotation of the cam assemblies through an angular position of an intermediate cam follower, the wells of the sub-assembly discs of the cam bearing surface are radially mis-aliged, and thereby fail to actuate the cam follower during rotation through an intermediate angular position.