A valve actuator assembly for an engine includes a movable poppet valve, and movable first and second spool valves. The assembly also includes an intermediate channel interconnecting the first and second spool valve, a driving channel, and a first and second feedback channel interconnecting the second spool valve and the poppet valve. The valve actuator assembly includes an actuator cooperating with the first spool valve to position the first spool valve to selectively allow high pressure fluid flow to the second spool valve and the driving channel to position the engine valve. The valve actuator assembly further includes a first and second on/off valve in respective fluid communication with the first feedback channel and the second feedback channel to selectively exhaust the first and second feedback channel to control motion of the second spool valve. The second spool valve includes a detent feature operable to maintain the second spool valve in a center biased position.