Indy 500 Engines: The Power!

by John Dickinson

The legendary Dan Gurney, in a mid-1990s letter to Road & Track magazine, expressed his concern to the motorsports world that engines used in the major categories of car racing were becoming increasingly “spec-like” due to rules encroachment of competition governing bodies, therefore limiting the engineering innovations so vital to automobile racing’s core essence. His references in that letter spoke to his deep concerns that an increasing “sameness” in the engines allowed in Indy Car, NASCAR, IMSA, Formula 1 (and other categories of car racing) were stunting engineering creativity in motor sport. He was concerned that the future of automobile racing was transitioning from the garages and drawing boards of racing’s true innovators to a handful of multinational power players that threatened to strip entrepreneurial excellence from the racing grids of the future.

In the case of the Indy 500, for example, engine technologies and advancements over the course of an inspired 107 years stagger the imagination. The extraordinary speeds of Indy Cars from the dawn of their creation have shocked the eyes and boggled the minds of onlookers for over eleven decades, setting records around the Speedway as the years have progressed. And although many factors have been responsible for the dizzying increases in performance over time, central to the equation are the high performance engines that have repeatedly powered Indy Cars to greater and greater speeds.

But if Dan Gurney were here today, he would point out that the extraordinary Indy pole qualifying record of 234.217— set by Gnassi team driver Alex Palou on May 20^th 2023 was virtually unchanged from that of Scott Brayton’s 233.718 mph and Arie Luyendyk’s 236.986 mph [not set on Indy pole day] in 1996. Prior to the late 1980s, when engine guidelines and suppliers were becoming increasingly standardized, steady innovations in engine performance significantly increased each year and were reflected in qualifying speeds. To be sure, from the time that Indy qualifying speeds surpassed 200 mph with Tom Sneva in 1978, speeds had to be carefully controlled due to the risks of cars becoming airborne, even in view of the superior aerodynamics that were being achieved. But clearly, engine performance targets of any level can be reached with far more than just the 2-3 permitted engine types of modern Indy Cars.

From 1910 to the mid-1980s, engine experimentation was one of the core fascinations of the Indy 500, providing engineers, racers, race teams, spectators and the motor sports media endless anticipation as to what engine type would reign at Indy qualifying and which would be victorious in any given year. Inevitably, during specific periods of Indianapolis 500 hundred racing over the decades, one or two engines would be dominant and one would reign supreme. These technology duals were often nearly as important as those between the cars that made Indianapolis famous and the drivers who piloted them.

From late 1928 forward, a number of car owners were on the “Miller 151 Four” bandwagon and some (car owner Bill White may have been the first) were using bored-out versions of the 151, increasing its displacement to 183-cubic-inches. Among many accolades, these engines were a mainstay for the short-lived Scofield organization, which operated the Harry Miller plant in 1929 and 1930. Spectacularly effective, Miller 151 engines powered several cars at Indy. The 1930 Indianapolis 500 starting line-up included seven nonsupercharged “naturally aspirated” Miller Marine 151 type Four engines, three of which were enlarged to 183-cubic-inches for more power. Shorty Cantlon, driving one of owner Bill White’s entries, qualified 3rd fastest for the 1930 Indianapolis 500. He finished the race in a solid 2nd place. 1930 was the high point of the automotive career of the Miller “151 Fours.” Although strong and dependable performers, they were simply not powerful enough to run consistently with the 8-cylinder and larger-displacement 4-cylinder machines on the paved 2.5 mile Indianapolis racetrack. And on dirt tracks they didn’t accelerate well enough to have a viable edge on the heavily modified Ford-engine-based racecars.

From 1934 into the 1970s, the Offenhauser engine was a dominant force in American open wheel oval track racing, winning the Indianapolis 500 27 times. From 1950 through 1960, Offenhauser-powered cars won the Indy 500, including all three podium slots and pole position in ten of eleven years. The Offenhauser engine, known as the “Offy” was an overhead cam “monoblock” four-stroke engine, developed from the genius of Fred Offenhauser and Harry Arminius Miller in several displacement versions. Originally sold as a marine engine, in 1930 it set a new international land speed record of 144.895 mph when installed in a racecar. After its upgrade by Leo Goosen to a double overhead cam, four-valve-per-cylinder 220 cubic-inch racing engine, variations of its design were used in Midget and Sprint racecars throughout the 1950s and ‘60s, with fuel system options of of carburetion or Hilborn fuel injection. The Offy’s distinct monoblock construction made it immune to common head gasket or cylinder stud problems, allowing for higher cylinder pressures, thus producing prodigious power, dependably. In 1946, with the name Offenhauser and its engine designs sold to Louis Meyer and Dale Drake, the engine dominated the Indianapolis 500, Sprint Car and Midget racing for two decades. A later turbocharged version of the “Offy” was then developed, which was highly competitive in the Indy 500, Indy Car racing and various forms of circle track racing for another 20+ years.

In 1937, brothers Ed and Bud Winfield, makers of racing carburetors, embarked on building an Indy Car for the new formula that had been announced. They secured sponsorship from one Lewis Welch, who made Ford parts and rebuilt Ford engines. Welch wanted a V8, and asked that it be named after his home town of Novi, Michigan. The Novi engine would be installed in a Harry Miller-designed front-wheeldrive chassis that had raced at Indy in 1935 and showed promise. Welch and the Winfields enlisted the matchless engineering expertise of Fred Offenhauser and Leo Goosen, the creators of the already-renowned Offenhauser race engine. The Novi became an invention like no other; a double overhead cam, supercharged race engine producing over 450 horsepower, yet reasonably compact and lightweight, that would take Miller racecars to new horizons and stunningly high speeds. The engine’s storied “shriek” was caused by its gear-driven centrifugal supercharger that turned at over five times the crankshaft speed, thus giving it a scream at full power. Its four-cam format with oversized valve design also gave it an exhaust noise much louder than other engines of its period, resulting in a deep-bass roar that sounded like a fighter plane. Some claimed that the noise actually rattled their teeth. Sadly, the engine overpowered both the car and existing tire technologies, ultimately killing its two top drivers and commencing a ten-year juggernaut toward success in the Indianapolis 500. But it was not to be. In the end, the Novi was called the greatest engine never to put a car in the Indianapolis 500 winner’s circle.

The double overhead cam Cosworth-Ford DFV 3-liter V8 was originally produced by the team of Mike Costin and Keith Duckworth, specifically for Formula 1, the pinnacle category of international auto racing. Initially developed in 1967 for Colin Chapman’s Team Lotus and sponsored financially by Ford Europe, the engine for many years became the dominant engine in Formula 1, first solely for Lotus but soon for many other teams. Although initially developed for Colin Chapman’s Lotus cars, DFVs became available to other race teams because their performance on the world stage benefitted the image and reputation of Ford, which wanted the engine’s successes as publicized as possible. From the late 1960s to the mid 1980s, many teams in Formula 1 won races and championships with Ford DFV power, with the only exceptions being Ferrari, Alfa Romeo, Renault, BRM and Matra, companies that designed, produced and competed with their own engines. Cosworth-Ford DFV were also used in other categories of racing, including CART Indy Cars, Formula 3000 and World Sportscar racing, where they also produced superior results.

In a focused effort to create a Ford competition engine that could defeat the then-dominant Offenhauser in the Indianapolis 500, in 1962 Ford commenced development on a lightweight, high-output double overhead cam V8 racing engine. Platformed upon the “small block” then-recently introduced Windsor 260, the “Ford 4-cam V8 Indy” employed special sand-cast aluminum cylinder heads and block, a forged steel crankshaft and redesigned valvetrain. Fed by a quartet of dual-choke 58mm Webers on a special intake manifold, displacement was increased to 255 cubicinches, producing 375 bhp at 7,200 RPM, but still not enough for dominance at The Brickyard. Among other key additives, forged aluminum pent-roof pistons maximized compression at 12.5:1, optimized by enlarged intake and exhaust valves which were fed by Hilborn mechanical fuel injection that incorporated eight individual throttles mounted centrally between the intake and exhaust cams. Result: 495 bhp at 8300 rpm and 330 foot-lbs of torque at 7000 rpm. And for Indy qualifying the redline was extended to 9200 revs! Result: super successes for Roger Ward in the first A.J. Watson rear engine Indy Car and for Jimmy Clark in the Lotus 38, which won the Indy 500 in 1965 with the Ford 4-cam Indy V8 engine.

Ten years after the mid-1960s creation of the extraordinary DFV Formula 1 racing engine came the DFX. The DFV, originally created by brilliant British engine designers Mike Costin and Keith Duckworth, although dominant in Formula 1 for over a decade, was capable of much more power. However, a fuel force technology such as turbocharging would be necessary. Initially, the 2.65-L turbocharged version of the DFV was developed privately by the American Vels Parnelli Jones team for Indy Car racing in the 1976 USAC season. This engine brought victory in the 1976 Pocono 500, plus two further victories at Wisconsin and Phoenix. Keith Duckworth, however, who felt that this “American” modified Cosworth constituted design infringement, established a Cosworth American operation as distributor of the turbocharged IndyCarspecification Vels Parnelli engine. Duckworth and Costin then poached two key engineers from the Parnelli team and set-up shop in Torrance, California. Henceforth the engine became known as the DFX, which went on to dominate American Indy Car racing just as the DFV had dominated Formula 1. The engine won the Indy 500 in ten consecutive years from 1978 through 1987, as well as winning all USAC and CART championships between 1977 and 1987 except one. For a brief time in the early 1980s, some DFX engines were badged as Fords. All told, DFX engines powered 81 consecutive Indy car victories from 1981 to 1986 and 153 victories total. By the time it was replaced, the DFX was developing over 840 bhp!