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

A little frothed up steam oil with saturated steam does wonders at "sealing" the piston/cylinder gap that simple air pressure certainly cannot!

Good point. Before steaming this engine, I pulled back the spring-loaded valve from the port face, and infused some steam oil. I also squirted some steam oil in the exhaust pipe and rotated the flywheel in reverse, sucking the oil up into the engine's innards. This was in addition to applying steam oil to the piston rod where it emerges from the cylinder. And you're right, it seemed to help a lot.

Paula