Square Piston Engine

Unusual square piston engine

Content Tools

Box 111, Pauma Valley, CA 92061

This unusual square piston engine is the work of Cecil Heyn, Box 111, Pauma Valley, CA 92061, and will be at the Vista, CA shout in June.

This month's engine has a crank case of aluminum which follows a square configuration. All parts are from bar stock. The 3 ounce copper gas tank is in the base, the crankshaft is 5/16th with a 1' stroke, the connecting rod is square brass, the piston is cast iron and ground and lopped to fit the receiver which is of two pieces and made of pressure die steel. There is very little expense with PV steel. The head is of cast iron, the valves are in sleeves pressed into the head. The valves are of stainless. The exhaust muffler is of brass and etched square. The configuration of the carburetor is square and made of brass and contains a check valve.

The photo shows the piston receiver with the piston in place. The engine turns. It is sitting on grid paper with 1' squares.

Cecil Heyn is a 75-year'old former tool and die maker who lives on the edge of an orange grove about 50 miles from San Diego, California.

There are two pairs of helica gears2 of nylon, 2 brass. 2 to 1 gears make up the side shaft configuration. Another pair of 2 to 1 gears runs the fly cubed governor which by a catch system holds open the exhaust valve to govern the speed. The wheels are of steel 1' wide, 41/8' diameter, with square spokes held to the crankshaft with tapered split bushings. The oiler with the sight glass is square and of brass, as are the 3 grease cups. All the metal parts are copper plated. The spark plug is also of square configuration. I've made lots of spark plugs! The wood box it sits on is of mulberry wood and is 4x4x8 and contains a 6 volt battery, coil and condensor. So far I have run this engine 300 to 400 hours and it is going good. It is one of the best engines we ever built. This engine has been lots of fun to build and draws lots of attention at shows. The little fan on the side keeps this engine very very cool. In fact, it never gets hot! You will note that all the bolts, where possible, have square heads and most of them are made of stainless.