The Cummins 2-Stroke Diesel Engine And Its Indy 500 History Explained

In 1931, Cummins put a version of its Model U diesel engine into a Model A Duesenberg and finished in 13th place at the Indy 500. The company returned to the Indy 500 in 1934 with two 135-horsepower supercharged diesel-engine race cars, one a four-stroke and the other a two-stroke. The two-stroke required 37 horsepower to drive the supercharger compared to the four-stroke’s 7-horsepower requirement. 

The two-stroke engine overheated, melting the pistons and fusing them to the cylinder liners, but finished the race in a cloud of smoke in 12th place. The failure prompted Cummins to abandon the two-stroke and focus entirely on four-stroke diesel engine development, at least for the next several decades. The four-stroke car finished in 19th place.

1952 was Cummins’ last diesel showing at Indy due to a rule change made afterward, with the company qualifying in the pole position. The car eventually finished in 27th place after running as high as 5th.