Advertised by the Downing Engine Works of Des Plains, Illinois in 1906 for $125.00, the 3 horsepower "Bill" engine is somewhat of an enigma. A patent was issued to William A. Downing for the design but it is not known how many were actually produced, if any. The very simple and attractive engine was probably intended for light duty work such as pumping water, powering a grinding wheel or a small dynamo, etc. A listing for the "Bill" can be found on page 141 of American Gasoline Engines Since 1872 by C.H. Wendel.

This is an approximate 1/3 scale model of the 1906 "Bill" engine. It runs on propane gas. On liquid fuel, due to the remoteness from the engine, the mixer soon gets cold from liquid fuel vaporization and after that the fuel doesn't vaporize very well which results in ragged operation. A propane demand valve was made for it and running on propane solves that problem. I have to presume that the prototype engine encountered the same problems (it may have ran on illuminating gas), but there was no propane to the rescue back in those days!

Engine operation on propane is a big plus. Valves and spark plug stay very clean and there is no smelly exhaust! I have been changing the crankcase oil every 10 running hours since break-in but it still looks new, so I am going to extend it to 20 hours. This wouldn't be the case using a liquid fuel.

"Bill" is machined and fabricated primarily of brass bar stock. The only castings used are the pipe elbows. The crankshaft runs on ball bearings, the cylinder has a cast iron liner and the piston is aluminum alloy.

The plans set consists of 18 pages of drawings plus a page of construction notes. Included in the plans are a propane demand valve, radiator/water pump/fan and details on mounting a Hall sensor and magnet so that electronic ignition can be used without contact points.

Specifications: Flywheel Dia.: 3.125", Cylinder Bore: 1", Piston Stroke: 1.250", Engine Height: 6.85"  Experience Level: 2