A 1905 Wolseley straight-12, 360 hp, petrol or oil marine engine

A straight-12 engine or inline-12 engine is a twelve-cylinder piston engine with all twelve cylinders mounted in a straight line along the crankcase.

Land use

Due to the very long length of a straight-twelve engine, they are rarely used in automobiles. The first known example is a 7.2 litres (440 cu in) engine in the 1920 French Corona car;[1] however it is not known if any cars were sold. Packard also experimented with an automobile powered by an inline 12 in 1929.[2]

The straight-12 has also been used for large military trucks.[citation needed]

Marine use

Some Russian firms built straight-12s for use in ships in the 1960s and 1970s.

MAN Diesel & Turbo 12K98ME and 12S90ME-C and the Wärtsilä-Sulzer RTA96-C are examples of contemporary marine engines in L-12-cylinder configuration. These are popular for propulsion in container ships.[3][4]


  1. ^ Burgess Wise, David (1979). The Illustrated Encyclopedia of Automobiles. New Burlington Books. p. 131. ISBN 0-906286-16-6.
  2. ^ "The Long-Lost Experimental Packard Straight Twelve - The Old Motor". theoldmotor.com. 4 December 2014.
  3. ^ "World's Largest Diesel: MAN's Record-Breaking 12S90ME-C". Archived from the original on 2017-06-14. Retrieved 2017-05-31.
  4. ^ "Archived copy" (PDF). Archived from the original (PDF) on 2017-05-17. Retrieved 2017-05-31.((cite web)): CS1 maint: archived copy as title (link)