Le Roi engines were first made in 1913, mainly for farm tractors. The earliest smaller engine I have seen is the Model 2-C dated 1919. The company made many different models with 1, 2 and 4 cylinders.
Around 1930, Le Roi started making engines with ball bearings on the main bearings and camshaft; these were all L-head engines. I have an original sales brochure from the early 1930s stating 87 percent of the internal parts of these engines interchange. In all of the engines I have disassembled, there is only one connecting rod, valve, and spring and piston size - 3-1/8-inch for all of the Model M and derivatives. The ball bearing engines are mostly 2-3/4-inch bore and they have the bearing made into the rod instead of an insert; they also have a smaller diameter valve.
Remember that these engines were primarily designed as power units. There were several models that used the same parts but changed the drive train, such as clutches, in-and-out boxes, transmissions, etc. There were many different flywheels, depending on the application. Some of the Model Ms had the power direct off of the crankshaft and some off of the camshaft for a gear reduction. They made the camshaft about 4 inches longer and added a ball bearing to help carry the load. If the engine was designed for a light-duty application, it had only one set of gears. For a heavy load, they doubled the camshaft gears.
Prior to 1940, the first overhead valve engine, the Model D-140, was developed. One of my books shows a spark plug change in 1940. They continued to make several different Model D engines and all of these engines are virtually identical to Allis-Chalmers engines. I have always been told that Westinghouse Air Brake Co., owned by Dresser Industries (who also owned Waukesha), bought Le Roi in 1954 and production was moved to Clinton, Iowa, to Climax Engine Co. The engines were called Le Roi Roiline. The Dresser engine website states Waukesha bought Climax in 1957.
Recently, I obtained a small booklet dated 1950 calling the engines "Le Roi Roiline" so obviously the buyout was earlier than 1957. Somewhere around 1958, all Le Roi production ceased and supposedly all company records were destroyed.
I called the Clinton historical society to see if they had anything on the engine factory or Le Roi engines. I was informed the Climax engine factory was closed down in the early 1980s and the historical society was presented with about eight large boxes of old company records. Evidently, no one had expressed an interest in them until now. The historical society is now going through trying to get an estimate of what is in the boxes. This may be a treasure and may answer questions about several brands of engines.
They also sent me a copy of a page from the book The Way Things Were, which is a historical perspective of the area and has an article from the newspaper when the plant shut down. Apparently, Climax developed the large engines that Le Roi made primarily for the oil fields. The largest engine Le Roi made is a 3,006-cubic inch, 400 HP V-12. The cylinders were made in pairs. They made 4-, 6- and 8-cylinder engines all using the same cylinders. There are still many V-12s running cotton gins today.
Le Roi also had the Centaur tractor that turned into the TractAir, which had a 4-cylinder engine and 2-cylinder air compressor on the tractor. Those were made for many years. I am always looking for more information to help people out. I now have 15 Le Roi engines, each one a different model.
Contact Ed Malcom, "The Le Roi Man" at: 39 Malcom Lane, Pineville, MO 64856; (479) 903-3005; (417) 226-4865 (evenings); firstname.lastname@example.org