The 1898 15 HP Palm is a four-cycle gas engine that can also operate as a steam engine. The base is an Ajax steam engine that was built in Corry, Pa., and the cylinder was built by the Palm Gas Engine Co. of Butler, Pa.
On the cylinder, you can see the steam chest and the throttle valve for steam operation on one side. On the other side of the engine is the valve chest, exhaust pushrod, mixer, intake valve, plus the ignition system – all parts for operating as a gas engine. There’s also a valve that you turn by hand to affect the conversion from one mode to the other.
Another interesting feature is that the exhaust valve is actuated not by timing gears but by a “wigwam” cam that alternately tracks on a low and high track mounted on the crankshaft, giving the every-other-revolution movement needed to operate the exhaust valve.