This 4-in-1 vacuum engine (or “atmospheric” engine) is fan cooled, and made from bar stock (no castings). It’s commonly called a “Flame Eater.” The engine features a torsion rod type valve mechanism, graphite valve seat, stainless steel cylinder liner, and graphite piston. The flywheel is 4” in diameter. An atmospheric engine can be built four ways: It can have an air cooled side crank, an air cooled center crank, or a water cooled side or center crank. The air cooled engines have an optional belt-driven cooling fan, which helps to cool during long running sessions. The engine still runs fine without this fan; however, with the fan in use the engine will run all day long and never get hot. Long runs or not, the fan adds an interesting element. All four versions of this engine use Jerry’s oscillating (twisting) side shaft mechanism to operate the head valve. His unique valve seat is made of self-lubricating, non-metallic material. This greatly reduces valve sliding friction, and virtually eliminates wear. The engine speed range is from 60-600 rpm.