Clessie Cummins - Truck Trend Legends

The Cummins Diesel Engine

Colin Ryan
Dec 26, 2013
The man who gave Cummins its name is Clessie Lyle Cummins, born in Indiana in 1888. Raised on a farm in preindustrialized times, Cummins was one of those kids who takes things apart. What made him different was that he could put them back together, and sometimes sneak in an improvement. His formal education went no further than the eighth grade, but that didn't stop him, at age 11, from pouring molten iron into self-carved wooden molds to make a steam engine to power the farm's water pump.
He quickly earned a reputation for being a whiz with a wrench. The Indianapolis Speedway circuit was not far away, and Cummins ended up in the pit crew of racer Ray Harroun, who was just about to enter the first-ever 500-mile event there. The year was 1911 and Harroun won.
Photo 2/5   |   Clessie Cummins
Even in those days, racing needed sponsors, and William Glanton Irwin, a banker from Columbus, Indiana, was one of Harroun's. Irwin was sufficiently impressed by Cummins to offer him a job as mechanic and chauffeur. So began a key relationship.
Cummins was working with gasoline engines, and designed and built his own in Irwin's garage. In 1919, he encountered his first diesel engine made by R.M. Hvid, developing single-digit horsepower. Rudolf Diesel had invented his eponymous engine technology about 20 years before. Naturally, Cummins was fascinated, so much so that he set up a company in Columbus, Indiana, to build those engines under license. His principal investor: William Irwin.
"In 1932, a bus powered by the Model H engine went from New York to Los Angeles in 91 hours on 365 gallons."
In June 1929, Cummins had another diesel engine, a four-cylinder that eventually went into a Packard that he drove the 700 miles or so to the New York auto show. Unable to exhibit at the actual show, he rented space opposite it. Interest was high and our hero went back to Columbus wondering how, without a production line, he was going to make all the engines he was sure he'd sell.
He needn't have worried. Even though the stock market crashed a few months later, Mr. Irwin was around to keep the company afloat. It just so happened that Irwin had a stake in a supermarket chain. Cummins diesel engines went into a couple of the chain's delivery trucks and soon proved themselves to be reliable, durable, and economical. This combination of vehicle and engine set the template for the road haulage industry.
On a coast-to-coast run in a Cummins-powered truck, a precipitous downhill stretch with a railway crossing at the bottom turned out to be just the place where the brakes failed. A freight train clattered across the truck's intended path at that very moment. Downshifting was the only option to slow the rig down, and it did, giving Cummins and his companions a precious safety margin of a few seconds.
Years later and officially retired, Cummins and his son Lyle went about perfecting his "engine brake" -- a valve lifter operated by a switch in the cab. This opens the exhaust valves slightly, releasing compression so the next cycle compresses again, slowing the vehicle. Nephew Don Cummins Jr. introduced Uncle Clessie to Louis Stoner, president of Jacobs Manufacturing (famous for making three-bit drill chucks), who took the plunge. The Jacobs Engine Brake was pronounced the 108th National Historic Mechanical Engineering Landmark by the American Society of Mechanical Engineers and still provides the basic principles for today's Jake brake.
The Model H engine that launched in 1933 formed the foundation for a line of successful engines. A 100,000-mile warranty, an industry first, was initiated in 1940. World War II was good for business. And the interstate building program of the 1950s only created more demand.
Cummins held 33 patents, which he kept when he retired from Cummins Engine Company at age 67 to form Cummins Enterprises. He was still tinkering with engines in the basement of his Sausalito, California, house right up to his death in 1968 at 80.
Not known for pithy quotes, Cummins did once say, "I have worked hard, put in long hours and enjoyed most of it." He left a mighty legacy and a company that made $13 billion in sales in 2010.



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