We have two of them at the high school where I teach, single-cylinder overhead valve engines, with permanently lubricated Torrington bearings at both ends of the connecting rod and the main bearing positions, so the crankcase is open to view- - - -no oil. The cylinder is tempered glass, with a plastic shield around it in case it gets overheated and shatters- - - -which is possible, I guess, but unlikely. For extended runs, I can connect an air hose and blow air around the cylinder for cooling. One of these engines has been there since 1970, and gets run regularly. I run it on alcohol, gasoline, Propane, natural gas, lacquer thinner, and just about anything else combustible. I can "Freeze" the piston in just about any position, top to bottom, by using a delay-flash timing light. The engine is made by a company called "Megatech" which makes training aids for school shops.
Jerry
