During the last year the two-cycle motor has come into prominence for use on automobile trucks. This is largely due to the fact that the two-cycle motor is of the slow-speed type, and that it has no valves or other parts which can easily get out of order. A good two-cycle engine will .run regularly, day in and day out, until the bearings become worn. As this only occurs gradually after a long period of use, the engine will show symp-toms of decreasing power, and will give warning that it needs attention. Then, if the owner lays up the truck for a day or two, the bearings can be readily renewed, and the motor will work as well as ever. The simplicity of this type is apparent from a glance at the photograph of the 3-cylinder Reliance motor shown in the illustration on page 323. The cylinders of this motor have a bore of 5% inches and a stroke of 5 inches. They are cast separately, with an integral water jacket completely surrounding the cylinder and head. The engine is of the usual three-port type, which dispenses with all valves of any kind whatever. The crankshaft is forged from a solid billet of special high-carbon steel, which has a tensile strength of 100,000 pounds. The crank case is cast of nickelaluminium alloy. The lower half may be easily removed for inspection of the crankshaft and bearings. The latter are of a high grade of Babbitt metal, and they are so arranged that they may easily be removed and replaced. The connecting-rod bearings may be adjusted by re-movlng plates in the side of the crank case. The crankshaft is provided with suitable counterweights, and at one end a spur gear drives the gear on the mechanical oiler; while the commutator and pump, which are placed on a vertical shaft above and below the center line of the crank case, are each driven by spiral gears. The pump is of the usual gear type, and the carbureter is of the fioat-feed variety. The company builds a 2, a 3, and a 4-cylinder engine for' use on their two, three, and four-ton trucks, respectively. Each cylinder is rated at 15 horse-power, and if any truck is underpowered for the work it has to do, it can be equipped with the next size larger engine. The Reliance trucks are all equipped with a heavy three-speed sliding gear transmission. The final drive is by chain from the countershaft to the rear wheels. The construction throughout is very simple and substantial, and of a kind which should stand up well in use.
This article was originally published with the title "A New Two-Cycle Motor and Truck" in Scientific American 97, 19, 348-349 (November 1907)