Essentally your idea is the same as Coates rotary valve system. Their system seems to FINALLY be getting some recognition, and we could see production examples on the road within 10 years. Check
here for more info.
As a side note, sealing and oiling issues are what have prevented other designs from gaining prominence. Rotary designs are difficult to maintain seal clearance over time due to the basic wearing patterns involved in the motion. They're also tough to lubricate without also contaminating the combustion chamber. There was another, more evolutionary poppet valve idea thrown around about 5 years ago involving vented valves, go
here for more info.