The Diesel That Dominated Indy

Number 28 was an oddity. The 1952 Indy 500 race rules allowed cars equipped with four-cycle diesel engines, twice as big as their gasoline powered counterparts, to race. “OK, so what?” you say. Clessie Cummins was a self-taught engineer and promotions whiz, much like Henry Ford (who was before him) had been. During his career he’d used the Indy 500 to showcase how durable his diesel engines were. By 1952, Clessie had retired, but the company, located in Columbus, Indiana, still fostered his belief that their engines could compete in the world’s most famous race. This is the story of the famous race car that dominated the Indy 500 just to prove a point!

Cummins build an inline-six, 401 cubic inch (6.6L), 380 horse powered, turbocharged, diesel-fueled race engine that featured an aluminum block, head and a magnesium crankcase. This was nothing short of revolutionary for its time! Cummins built the engine and then, to take full advantage of this monster powerplant, turned to renowned chassis builder Frank Kurtis to build the car that went around it! Frank mounted the motor on its side in a radically low chassis built by his shop, Kurtis Kraft.

Kurtis recommended that Fred Agabashian be hired to pilot the beast. Come spring, #28 was tested in a wind tunnel and then at the Indianapolis Speedway. The car proved to be every bit as powerful as expected and more of an engineering success than wildly dreamed of! The 3,100-lb car took the pole position in qualifying with a speed of 138.010 mph! It also outran Ferrari’s 12-cylinder race car by nearly 4 mph -no small accomplishment there! The only real problem was that the car ate up tires during qualifying. It was huge and heavy and ran like a scalded cheetah. With that M.O., something would flesh out to be a weak link. That link showed up in the tire technology – or lack there of.

Although qualifying tore up #28’s tires, the race day strategy would take into account this week link and make provisions to compensate for it. The car would pit once during the race to tactically swap tires. She had been built with a 50-gallon tank and could averaged 10 to 12 miles a gallon; so #28 could make 500 miles without a fuel stop if they wanted. However, because of the tire change, Cummins took full advantage of the pit by planning to start the race with enough fuel for 80 laps and then for tires and fuel in the same pit stop! This way they’d take advantage of a lighter starting configuration and not tax the car to its design limits.

The diesel was balky at the start and never led, but it did run strong. Once she reached her stride, she took fifth for quite a few laps. But on the 70 lap, it was all over for the diesel that could. About that time the car began to belch black smoke. The experimental car pitted at the 175-mile mark. The crew discovered that the engine was overheating. From there she was rolled into the garage and withdrawn from the race, officially due to turbo failure. It turned out, poor design placement of the turbocharger allowed it to suck up rubber particles into the inlet, which clogged it up. Once that happened, #28 was done.

On the day after the race, J. Irwin Miller (Cummins Chairman of the Board) ended the cars racing career. “There are no plans for racing the car next year,” he said. “Right now, we want to apprise the value of what has been done up there and see what we’ve learned before we even talk about anything else.” Miller went on to say “that the car with experimental equipment has a very poor chance of winning. But we learned what we wanted whether the car won or not.”

Years later, Don Cummins summed up the #28 contribution to Indy history by stating: “The whole reason for being there was to draw attention to the fact that we were producing these engines…If anybody thought it was a Mickey Mouse engine, we wanted to be able to say, ‘Hey, the engine in your truck, this thing you can buy, sat on the pole at Indianapolis.'”