Indy 500 History 1920-1929
In consideration of safety, Indy 500 race cars have seen numerous engine-size rulings throughout it's history. The 1920's saw three of them, as well as the emergence and dominance of Harry Miller-built cars and engines. Cars built by Miller won the Indianapolis 500 nine times, and another three were won with his engines in other competitor's chassis.
1920 Indy 500
New rulings for 1920 reduced maximum engine displacement from 300-cid to 183-cid (3,000cc). This size was purposely chosen to conform with European regulations. Entries had to achieve an 80-mph minimum speed to qualify for the race. The four-lap (ten-mile) qualifying distance was introduced this year, and is the procedure presently being used today.
Gaston Chevrolet broke the dominance of European-built cars, winning the 1920 race in his eight-cylinder Monroe-Frontenac. Gaston was also the first driver in Indy history to finish the race without making a tire change. Notable finishes include the Duesenberg Racing team, finishing in 3rd, 4th and 6th place.
Miller 183 Engine
Harry Miller was a race car builder who designed cars and parts not only to minimize weight and wind resistance, but for simplicity and attractiveness. Together with Leo Goossen and Fred Offenhauser, Miller designed and built a 3.0 litre (183 cubic-inch) straight-eight engine for competition. The double-overhead camshaft, four valve per cylinder motor was inspired by the 1913 Peugeot Grand Prix engine. About a dozen 183's were built (before the 122 cubic-inch formula was enacted in 1923). Power output was about 150 horsepower.
"Richards" race cars, first run at the Indy 500 in 1919, were back in 1920 with a new motor.
The 181 cubic-inch, twin-cam engine was built by Riley Brett, Cotton Henning, and W.W. Brown.
With the exception of a modified Hudson 'Super-Six' crankshaft, the motor was completely hand-machined.
The block and crankcase units were cast of aluminum, and the detachable iron heads were cast in three blocks of two cylinders each. Each cylinder used four valves with individual runners. The cams actuated the valves through radiused cup-type cam followers, very likely the first example of this design.
The 24-valve engine used an elaborate front geardrive, with 11 straight-tooth gears.
Placed into the 1919 chassis, the Richards car finished the 1920 race in 11th place.
1921 Indy 500
For 1921, two Richards cars, now called 'Junior Specials', competed in the Indy 500. A second DOHC engine was built and both motors were fitted into Miller chassis'. Both cars experienced steering-box trouble, and best finish was 15th. That day, it was Tommy Milton in his straight-eight Frontenac (built by Louis Chevrolet) driving into the winner's circle. 1919 Indy 500 winner Howdy Wilcox finished in last place, making him the first driver to finish in both first and last places. Also notable was the Duesenberg Racing team, whose cars finished 2nd, 4th, 6th and 8th.
1922 Indy 500
The 1922 Indy 500 was dominated by Duesenberg cars, who finished 1st, 2nd, 4th, 5th, 6th, 7th, 8th and 10th. Winner Jimmy Murphy's average race speed was 94.5 mph. He was the first Indy 500 winner to lead both the first and last lap of the race. His Duesenberg was powered by a Miller 183 engine.
Miller 122 Engine
New requirements decreased engine displacement to a 2,000cc, 122-cubic-inch formula. Miller's new engine used a bore and stroke of 2.33" x 3.50" to give the 2.0 litre displacement. Cylinder heads were cast integrally with the cast iron cylinder block and sat on a common aluminum crankcase. Using two valves per cylinder, the twin cam motor produced around 120 horsepower. This figure increased to 200 with the use of a supercharger. A total of seven Miller 122's were prepared for the 1923 Indianapolis 500.
1923 Indy 500
Since riding mechanics were no longer required, Harry Miller was able to build cars with a very thin chassis with equally narrow (18 inch wide) bodywork. The entire car weighed only 1,350 pounds, helping the Miller 122 achieve a top speed of over 140-mph. Tommy Milton, driving a Miller 122, won the race for the second time, making him the first two-time Indy 500 winner.
1924 Indy 500
Duesenberg Racing finished first this year, running the first supercharger on an Indy car. Lora L. Corum was co-winner, being replaced by Joe Boyer on lap 109.
1925 Indy 500
Pete DePaolo was the first Indy winner to average over 100-mph, with his recorded speed of 101.13 mph. This is the first time the speed goes past the century mark - a record that will stand for seven years. Duesenberg Racing finishes 1st, 3rd and 8th. A front-wheel drive car, built by Miller, is used for the first time at the Speedway. The privately-owned entry, driven by Dave Lewis and Bennett Hill, finished in second place.
1926 Indy 500
Engine displacement was decreased again, now set at 91 cubic inches (1490cc). However, due to a shortage of 91-cid parts and engines, many race teams ran 122-cid motors that were destroked/debored to 91-cid. This year saw the first rain-shortened Indy 500 race. After 160 laps, Frank Lockhart took the checkered flag with a two lap lead. Lockhart drove a Miller race car, owned by Peter Kreis.
1927 Indy 500
Piloted by George Souders, Duesenberg Racing finishes in first place.
1928 Indy 500
Winner Louis Meyer’s car was a supercharged Miller Special - nine of the top ten finishers that day were built by Harry Miller. This was the most dominant display of one car manufacturer in the history of the Indy 500.
1929 Indy 500
Sadly, driver Bill Spence was killed after making contact with the inside wall in turn two. At the end of the race, Ray Keech took the checkered flag (Keech had previously been a land speed record holder, clocking 207.55 mph at the Daytona Beach Road Course on April 22, 1928).
Photos courtesy of www.MillerOffy.com