The "Bob Byrne Offy"
Ca. 1955 OFFENHAUSER-POWERED SPRINT CAR
Engine No. 60
White, Dark Red Frame and wheels/Red interior
Engine: Dual overhead camshaft inline four-cylinder, 220+ cubic inches, Hilborn mechanical fuel injection; Gearbox: 2-speed manual; Suspension: Live axles with transverse leaf springs and Houdaille lever shocks; Brakes: Hydraulic rear wheel drums. Single Seat.
Building sprint cars has been a cottage industry in America since horses began to be replaced by horsepower on America's oval tracks. The formula has been fairly simple: A set of strong, readily available frame rails, live axle suspension from an early Ford a tightly wrapped lightweight body of aluminum enclosing the engine, a single central seat and a big steering wheel connected to a drag link and the steering arms.
Using the Ford's transverse leaf springs and a set of lever shocks, typically modified Houdaille hydraulic shocks once they became available, location was provided and torque reaction taken by split radius arms. Brakes were hardly necessary and therefore were located only on the rear wheels. Rugged was important. Tracks were rough, packed clay that quickly developed ruts and potholes. The driving was as rough as the tracks and the little nerf bars did little to protect the cars from each other or from the walls.
What was most important was the powerplant and far and away the best engine was the Miller, Offenhauser, Meyer & Drake dual overhead camshaft four cylinder. Proven over decades in all forms of motor sport, by both professional and amateur drivers, on dirt and pavement from bull rings to the high speed banking of Indianapolis. The Offy, as it became almost universally known after Fred Offenhauser took over its development, production and support from Harry Miller, proved itself in the most demanding situations and encouraged continuing development up through the turbo era. One of the most important developments was Stu Hilborn's mechanical fuel injection. It added about 15 to the Offy's horsepower and improved throttle response as well. It wasn't inexpensive but it was so much better than balancing a bunch of carburetors it quickly proved its value to serious racers.
The Sprint offered here comes from the estate of Bob Byrne and unfortunately Bob did not communicate much information about it to his heirs. The standard of construction is consistent with Midwest sprinters, the cosmetic presentation is quite good.
The engine is an Offenhauser numbered 60 on the cam cover ID plate. It has not been run in some time and when delivered for cataloging was not turning over. The cylinders have been lightly oiled and hopefully will be freed up before the auction. The cylinder stroke, measured between two adjacent cylinders at or close to dead center, measures approximately 4 3/8 or 4½ inches which indicates a displacement of over 220 cubic inches. It is fitted with Hilborn fuel injection, a chromed set of headers and exhaust pipe and has a standard Ford-based rear axle without a quick change.
There are hydraulic brakes on the rear wheels only. The suspension is highly detailed and mostly chromed. The fuel tank, all the fuel lines and the hand pump have been removed which, in view of the effect of alcohol fuel on metal parts, is probably very good news for the next owner. Additional research is ongoing and more information may be available at the auction.
This is a mechanical restoration project with good, sound components and little need for cosmetic work. Offenhauser-powered sprint cars are the gold standard in American oval track racers. The engine traces its ancestry back to the earliest days of the automobile in America and legendary builders, designers, constructors Harry Miller, Leo Goosen and Fred Offenhauser. Vintage oval racers are featured at the Monterey Historics this year and an Offy-powered sprint car is a welcome participant there and at other interesting and enjoyable events for historic oval cars.