Number 28 was a rarity. The 1952 Indy 500 race rules allowed cars equipped with four-stroke diesel engines twice the size of their gasoline counterparts to compete. “OK and so what?” you say. Clessie Cummins was a self-taught engineer and promotional genius, much like Henry Ford had been (before him). During his career, he used the Indy 500 to show how durable his diesels were. By 1952, Clessie had retired, but the Columbus, Indiana-based company still fostered his belief that his 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 made a 401-cubic-inch (6.6 l), 380-horsepower, turbocharged, straight-six diesel racing engine that featured an aluminum block, magnesium cylinder head and crankcase. This was nothing short of revolutionary for its time! Cummins built the engine and then, to get the most out of this monster engine, turned to renowned chassis builder Frank Kurtis to build the car around it. Frank mounted the engine sideways on a radically low chassis built by his shop, Kurtis Kraft.
Kurtis recommended that Fred Agabashian be hired to pilot the beast. When spring came, the #28 was tested in a wind tunnel and then at Indianapolis Speedway. The car proved to be every bit as powerful as expected and more of an engineering success than I wildly dreamed of! The 3,100-pound car took pole position in qualifying with a speed of 138.010 mph! It also outperforms Ferrari’s 12-cylinder race car by almost 4 mph, no small feat! The only real problem was that the car ate the tires during qualifying. It was huge and heavy and ran like a scalded cheetah. With that modus operandi, something would become a weak link. That link appeared in the tire technology, or lack thereof.
Although qualifying broke the tires of the no. 28, the race day strategy would take this week’s link into account and take action to compensate for it. The car would pit once during the race to tactically change tires. It had been built with a 50-gallon tank and could average 10 to 12 miles per gallon; so the #28 could do 500 miles without a fuel stop if they wanted to. However, due to the tire change, Cummins made the most of the pit stop by planning to start the race with enough fuel for 80 laps and then tires and fuel at the same pit stop. This way they would take advantage of a lighter starting setup and not burden the car with its design limits.
The diesel was reluctant at first and never led, but ran strong. Once he hit his stride, he was in fifth place for quite a few stretches. But by lap 70, it was all over for the diesel that could. At that moment the car began to vomit black smoke. The experimental car pitted at the 175-mile mark. The crew discovered that the engine was overheating. From there, she was taken to the garage and removed from the race, officially due to turbo failure. It turned out that the poor placement of the turbocharger design allowed it to suck rubber particles into the intake, causing it to clog. Once that happened, #28 was done.
The day after the race, J. Irwin Miller (Cummins Chairman of the Board) ended the car race. “There are no plans to race the car next year,” he said. “Right now, we want to learn the value of what’s been done there and see what we’ve learned before we talk about anything else.” Miller went on to say “that the experimental team car has very little chance of winning. But we learned what we wanted whether the car won or not.”
Years later, Don Cummins summed up the #28’s contribution to Indy history by stating, “The only reason it was there was to draw attention to the fact that we were making these engines… If anyone thought it was an engine From Mickey Mouse, we wanted to be able to say, ‘Hey, your truck engine, this thing you can buy, sat on the pole in Indianapolis.