I want to start today’s write-up first and foremost for apologising for not being able to post being able to post for day 50 yesterday, I have a busy schedule having to balance work and two radio shows my write-ups and by the time it came to writing yesterday’s article it was 1am in the morning and I simply did not have the energy to get an article done in time. I apologise for this and promise to post ‘A Banzai Manouver’ on a later date. But whilst my own energy and endurance may have been called into question over the last few days the same cannot be said for the subject of our next update.

With over 27 500 victories over a career spanning over half a century, the Offenhauser V6 engine can stake a legitimate claim to being the greatest engine ever to grace the Indianapolis 500, a sturdy and reliable unite whose power output and ease of use saw it go become a byword for success when it came to the Brickyard. Such was the level of dominance shown by the unit in it’s heyday that during the 1950s it was commonplace for Offy engines to power the entire 500 field, while it’s longevity saw it remain a competitive unit in Indycar racing well into the late seventies.

The history of the Offenhauser engine can be traced back to the early days of the Brickyard, when at the age of just 15 years old automotive engineer Fred Offenhauser earned himself a job at the thriving Miller car company in California, who had begun to establish themselves as one of the dominant forces in the early days of American auto racing. After working remedial jobs during his early years with the firm, Offenhauser worked his way to the superintendent position within Miller’s shop department, and soon began working exclusively with Miller himself over the development of a new power unit originally intended for marine usage. After Miller was forced to declare bankruptcy following the 1929 stock market crash, Offenhauser decided to purchase the Miller factory and develop the engine he designed under his own name, switching the unit’s focus from the Maritime world into that of Motor Racing. With backing from Earl Gilmore, Offenhauser built the 1st 97 cubic inch Offy engine for midget racing in 1934 winning it’s first ever race later in the year with midget car veteran Curly Mills behind the wheel.

Following this early success in the junior Formula, Offenhauser decided to take the development of his unit to the next step, developing the former midget engine into a four cylinder twin overhead unit designed to be used for top level competition including Sprint and Dirt Car racing. It was using a variant of this unit in 1935 that Kelly Pittolo was able to claim the company’s first victory in that season’s Indianapolis 500, with Wilbur Shaw and Mauri Rose both claiming victories for the unit prior to the outbreak of World War II, by which point the Offy had emerged as ago-to unit for many aspiring 500 competitors.

Most of the Offy’s appeal during those years stemmed from the high levels of power that the engine was able to generate, with the original 255 variant of the engine able to develop 420bhp depending on the choice of carburettor of fuel injection used by its owner, although some larger variants of the unit were reported to generate outputs of 3 hp per cubic inch, a figure large even by today’s standards. As well as its strong power levels the engine was also comparatively cheap allowing the unit to be much more accessible with more undefended Indy outfits, whilst It’s its monobloc construction meant the engine was not vulnerable to head gasket or cylinder stud problems, allowing for higher cylinder pressures and thus increased reliability when compared to it’s rivals. It is for these reasons that by the end of World War II the Offenhauser engine became the weapon of choice for racing drivers not only at Indianapolis but also in American auto racing in general, with the unit picking up 17 successive wins at the Brickyard between 1947 and 1964, a run which included the firm claiming 10 pole positions in 11 years as well as clean sweeps of the podium between 1950 and 1960.

With the introduction of rear engines to the speedway in 1961, culminating with Jim Clark’s victory in a Lotus Ford in 1965, the Offenhauser began to lose its domination over Indy car racing, although it remained a competitive winner through the mid-1970s even with the advent of turbo-charging. During this time, power outputs for the machine were reported to reach over 1,000 horsepower with three bar of boost pressure, a figure which was reduced to 770bhp by the time of the final incarnation of the engine in 1969. Although the engine played second fiddle when compared to the more powerful rival Ford engine, the Offy’s reliability and durability still made it an ever-present threat when it came to Indianapolis, with Johnny Rutherford giving the unit it’s 27th and final victory at the Brickyard in a rain shortened event in 1976. Although other drivers would pilot Offy engines at the brickyard after that victory, new regulations had rendered the now 43 year old unit uncompetitive when it came to the speedway. The last Offy powered entry in the series coming at Pocono in 1982 in an Eagle chassis driven by Jim McElreath.

Although other engines at the speedway have proven to be more powerful and arguably more technically impressive at the Brickyard, the Offy’s unprecedented level of success makes it one of the standout units ever to grace the speedway, and the fact that it remained competitive even forty years after it’s introduction is a testimony to the longevity and legendary status that the unit has earned during the it’s time at the Brickyard.

For today’s video there is nothing else I could really show then a series of Offy roadsters in action at a classic car exhibition at Michigan International Speedway. Listen to that engine note when the machine fires up!