Abstract: A rotary valve system for a motor and the like includes a flow conduit and rotary valve means interposed in the flow conduit. Intermittent sealing means are provided for preventing flow through the flow conduit, comprising a sealing surface intermittently positionable in stationary, sealing relationship across the conduit. Means are also provided for moving the sealing surface into such stationary sealing relationship with the flow conduit, and out of sealing relationship with the flow conduit in a manner correlating with the operation of the rotary valve means, to facilitate sealing as the valve operates.