Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Considering the H70 series engines serious design  (reverse cam timing, non-lubricated crank, rod & piston, etc,) issues & Not exactly built like a Swiss watch loose,.....Why would one expect the original Oem Cylinder groove & O-ring Dimensions + O-ring Shore A durometer to be anywhere Near functional sealing optimal ?? ....Fine tuning the original 2 groove cylinder O-ring ID/OD/Cross Section & Durometer selection will most likely correct the leaking issue.....2 x Bad = More Bad !!