Building Model Engines

Model gas engine built from castings

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Orillia, Ontario, Canada L3V 1G6

Shown is my model gas engine. I built this engine last winter from castings supplied by one of the advertisers in G.E.M. It has a ' bore and 1' stroke. The flywheels are 4' in diameter. It runs best on regular gasoline and the mixer or carburetor uses a sewing needle to control the mixture. I used oak planks to make the base and the gas tank is a piece of brass tubing off an old sink drain. The base contains the coil, condenser, and battery, which makes it all self-contained and easy to run sitting n the shelf.

I have displayed this engine at several steam shows and fairs and it always draws a crowd. Some people get quite angry when I insist that it runs on its own. They think there is a trick to it somewhere. I think that it ran about 100 hours this past summer at the shows. One full gas tank (3 ounces) will run about five hours if it is just idling. The governors are quite sensitive and will keep the hit and miss cycle going even when the speed is slowed right down. However, as soon as a load is applied, it jumps to life and hits every time until the RPM's come up again. When the load is removed, the firing stops completely and it coasts right down to the occasional 'putt' followed by several seconds of whirring timing gears and coasting flywheels. I'm sure this type of running will be familiar to anyone who owns a hit and miss engine. Many people however, don't understand what keeps it going because they are only used to throttle-governed engines.

I'd like to correspond with anyone in Gas Engine Country who is also building model engines. My current project is a 1915 Holt Caterpillar engine. It is a four cylinder with 1' stroke and 1' bore. If I can get enough information about the Holt 75 tractor, I would like to model the whole thing. According to the scale of the engine, the finished model would be about 32' long. These tractors had tracks at the back and one large wheel on a swivel at the front.

As the costs of transporting full size equipment continues to rise I expect to see miniatures increase in popularity. I expect that there are others in the Gas Engine Hobby who have a special make of engine which is a favorite or a 'dream engine'. For most of us the only way of owning one is to build a model of that very special engine. They can be just as much fun to run as the real thing!