During the 1920s, a 1997cc sports model was marketed and in some models sleeve valve engines were used.

This multi valve engine has a claim to be the first to be used in a "mass produced" car.

The M111.920 is a 1.8 L (1799 cc) 16 valve engine.

This had a poor reputation for handling, however, and was not really built for the more powerful four valve engine.

The vehicle had a tilt steering wheel and an overhead valve engine.

One notable example is a large 1889 Corliss valve horizontal single cylinder steam engine.

Six-cylinder sleeve valve engine, you know there was only six of these ever made.

A new range of cars were shown in 1924 now with overhead valve engines and front wheel brakes but production remained limited.

This was a direct injection, four valve engine, which avoided the pumping losses of using a throttle.

Development had lagged with the continued use of two valve engines, but new funds enabled a technological move forward Ducati needed at the time.