Ian Wagstaff finds proof that diesels have had a hand in the history of motorsport.
There has been much talk about what engine is to be used for the Indianapolis 500 race in 2012. The word ‘diesel’ was mentioned. This, though, is unlikely to happen; even Audi’s motorsport engine guru Ulrich Baretzky suggested an in-line four petrol unit. However, there is precedence.
On the first day of time trials for the 1952 Indy 500, Freddie Agabashian drove his Cummins Diesel Special onto the 2.5-mile oval. After two quick warm-up circuits he took the green flag that signified the start of his four lap qualifying run. On his first lap he recorded an impressive 139mph that onlookers could hardly believe. The next three were not much slower and, with chunks of rubber tearing off a rear tyre, his final average was 138.010mph – a new record. A diesel would sit on pole position for the Indianapolis 500.
The idea of entering a diesel car for the Indianapolis 500 dates back to 1931. Stock engines were being encouraged and perhaps the most outstanding achievement of any of them was that of the enormous Duesenberg entered by Indiana-based Cummins, the first diesel to race at ‘The Brickyard’. Powering the car was a slow-speed, four-cylinder, four-valves-per-cylinder marine engine. Driven by Dave Evans, it went the full distance on 31 gallons of fuel (costing a total of $2.55) not having to make a single pit stop. Evans’ riding mechanic Thane Houser did signal to the pits to enquire when they should come in but there was no answer and they kept plodding on. After the race it was discovered that the crew member in charge of hand signalling had lost the piece of paper with the ‘key’ to those signals. The miscreant’s name was Jimmy Doolittle, already a well-known figure in air racing and later to lead the famed Doolittle Raid on Japan.
Twelve cars finished ahead of the diesel that day but that was not the point, the objective of the exercise had been to prove the diesel’s durability, not its speed. Three years later Cummins entered two cars, one with a two-cycle motor and supercharger, the other with a four-cycle engine. ‘Stubby’ Stubberfield finished in 12th place while Evans went out with transmission troubles. Point proven, the diesels disappeared until after the War.
In an attempt to encourage variety for 1950, the race organisers allowed diesels a large displacement advantage. Cummins was attracted back using a six-cylinder JBS-600 truck engine increased in size to 401 CID and using a Roots-Type supercharger. Figures were seen on the dyno of 340bhp at 4,000rpm on 15-psi boost pressure. California-based Frank Kurtis was contracted to build a chassis.
Cummins could use one of its own trucks to transport its racecar to the Indianapolis Motor Speedway. Sales soared after the car’s performance in qualifying
With Jimmy Jackson at the wheel, the car qualified for the back row of the grid and dropped out of the race on the 52nd lap with supercharger-drive failure. Don Cummins went away to improve matters for 1952. Kurtis built a new car with an innovative, low slung design – probably the lowest at the Speedway – based on weight control and a desire to lower the centre of gravity. The engine was completely on its side and an offset driveshaft not only assisted in reducing height but also enhanced cornering. A crude turbocharger was installed, the first to be used in the 500.
Like its 1930s predecessors, the 1952 car was frugal and could probably have completed the race on just 50 gallons. However, weight and subsequent tyre wear was a problem. So too was the turbocharger, which, because its air inlet was just inches from the track, acted like a vacuum cleaner and sucked in dirt.
The respected Agabashian was concerned that the diesel’s massive power could lead to protests being made so, in initial practice, he kept his speed down and there were those who wondered if he would even qualify. Then came ‘pole day’ and he let the car off the leash. The result was one of the biggest upsets in the history of the Speedway. In the race, Agabashian ran fourth for many laps before that turbocharger became blocked. Cummins was aware that pressure from other competitors would probably result in a reduction of permitted engine capacity for diesels if it was to return. However, it had ably demonstrated the potential of the diesel; Cummins truck sales increased dramatically and it was a case of job done. Three-time Indy 500 winner Wilbur Shaw tested the car a few days after the race, but the diesels were never to return.