In the second half of the 1920s FIAT began the technical development and then the production of a series of fast four-stroke diesel engines with direct injection with a mechanical piston pump. The characteristics and performance of these engines made them particularly suitable for both industrial and naval use. Their construction was based on a semi-modular layout which allowed the production of a vast range of engines with different displacement and maximum power output from 24 to 140 HP. This was achieved through the alternative use of 3 different cylinder bore (120, 140 and 170 mm) and a variable number of in-line cylinders from 2 to 6. The engine on display, named V 123, has 3 cylinders with 120 mm bore.