I had sent Hagar a message last night kind of trying to explain how the engine functioned. I am not sure if I am that good at explaining things. If you see this Hagar it is a sketch of how the rear case or chamber works. Nothing on it is to scale. You had asked if there were any type of seals in it to keep air from leaking. Other than my O-rings used to get the air from the base to in the rear chamber there are none. With a rotary valve or cam you just try for the best fit you can get in the bore of the chamber. I did lap the two and feel I got a perfect fit. On the engine I somewhat copied, the air valve from (Rudy K's Radial 5) His valve or cam has one groove and one flat and the exhaust is sent through a hole into the hollow shaft and out the rear of the engine. On mine I used 2 grooves and each has its corresponding flat so one is intake air and one is exhaust air. The intake flat shoots air into each of the 9 ports as it passes them and the exhaust flat sends the air out 4 ports I put on the bottom side of the chamber (one each in the #4 thru 7 position. The flats are not spaced as shown in the sketch. It was drawn that way to see them better. Hope I didn't bore anyone to death.
Gary