A system for actuating an engine valve includes a linear machine having a coaxially aligned field assembly and armature assembly. In one embodiment, the field assembly reciprocates relative to the armature assembly to actuate the valve. One configuration has a field assembly with a number of axially oriented annular permanent magnets separated by a ferromagnetic material and mounted on a non-magnetic shaft. The ferromagnetic material is preferably a compressed powdered metal which is microencapsulated with insulating material to reduce the formation of eddy currents. The preferred construction provides a reluctance force which helps maintain the valve in an open or closed state without any current applied to the armature. The system may also include an inductor and/or a capacitor tuned to the natural frequency chosen to provide regenerative actuation at a predetermined natural frequency.