Straight-eight engine

1933 Bugatti DOHC straight-8 in a Type 59 Grand Prix racer.

Straight-eight engine with firing order 1-4-7-3-8-5-2-6

The straight-eight engine or straight-8 is an internal combustion engine with 8 cylinders. Sometimes it is called an inline-eight engine. All eight cylinders are mounted in a straight line along one crankshaft. It can be powered by different types of fuels, including gasoline and diesel.

A straight-8 can be designed with balanced engine forces. Crankshaft vibration is present in all engines. The use of a harmonic damper is needed at the end of the crankshaft. Without the damper, the vibrations may lead to engine failure.

The straight-8 is a smooth running engine. This made it popular in luxury and racing cars of the past. The length of the engine required a long engine compartment. This makes the basic design unacceptable in modern vehicles. The design has been replaced almost completely by the shorter and sturdier V8 engine. Mercedes and BMW made straight-8 aircraft engines during World War I. The engine for aircraft use provided good aerodynamics.

Performance and racing cars

The Duesenberg brothers introduced the first successful straight-8 racing engine in 1920. Their engine placed third, fourth and sixth at the Indianapolis 500. The following year one of their cars won the French Grand Prix. The straight-8 was the engine design of choice from the late 1920s until the mid-1950s. Bugatti, Duesenberg, Alfa Romeo, Mercedes-Benz and Miller built successful racing cars with high-performance straight-8 engines in the 1920s and 1930s.

Straight-eight Engine Media

• 

  Delage straight-eight racing engine

• 

  Duesenberg Model J engine

• 

  REO Straight 8 from 1931-1934

• 

  1940s Oldsmobile straight-8 engine

• 

  1932 Alfa Romeo 2,336 cc (142.6 cu in) DOHC Roots supercharged straight-8.

Books

• Daniels, Jeff (2002). Driving Force: The Evolution of the Car Engine. Haynes Publishing. ISBN 1-85960-877-9.
• Georgano, G.N. (1985). Cars: Early and Vintage, 1886-1930. London: Grange-Universal.
• Ludvigsen, Karl (2001). Classic Racing Engines. Haynes Publishing. pp. 22–25. ISBN 1-85960-649-0.

Other websites

• Davies, John William. "Welsh Motor Sport - Cars". John William Davies. Archived from the original on 2012-10-09. Retrieved 2009-01-20.
• van Damme, Stéphane. "Histomobile: Leyland - 1920s". Histoire de l'automobile. Stéphane van Damme. Retrieved 2009-01-20.