Diatto

Italy, 1905 – 1927

(1) Diatto-A. Clément Vetture Marca Torino, Turin, 1905 – 1909

(2) Società Officine Fonderie Fréjus Vetture Diatto, Turin, 1909 – 1918

(3) Fonderie Officine Fréjus Automobili Diatto, Turin, 1918 – 1919

(4) Automobili Diatto, Turin, 1919 – 1923

(5) Autoconstruzioni Diatto, Turin, 1924 – 1927

The Diatto railway engineering concern entered the automobile industry by allying themselves with Adolpphe Clément (who joined the board at Diatto) to build Clément-Bayard cars under licence in Italy. Curious 2- and 4-cylinder Diatto models were marketed between 1906 and 1910; all had T-head engines, ht magneto ignition, and shaft drive, though latterly the largest Diatto, the 4.8-litre 28/35, could be had with side chains as well, and in 1908 there was a short-lived 4.1-litre six. Clément’s resignation in 1909 coincided with the Diatto company’s first monobloc engine, the 2.9-litre 16/20, but this was still of T-head type. The L-head configuration did not arrive until the 2-litre 12/15 of 1910 (sometimes known as the Fréjus); this evolved into the staple pre-World War 1 Diatto, and grew up to 2.4-litres with a 4-speed gearbox by 1915. In that year Scacchi and Newton were absorbed, and Diatto turned over to trucks and Bugatti aero engines, though new 2.7-litre and 4-litre fours were announced bij Diatto in 1916.

The Diatto firm made a few 1½-litre Bugatti Brescias in 1919 under the Diatto Tipo 30 desination, but their own post-war programme consisted of a 2.7-litre 4-cylinder in the traditional idiom, and Diatto Tipo 10, a simple light car with 1018cc sv engine, 3-speed egearbox, and plate clutch. This attempt to compete against Fiat had been abandoned by the end of 1922, in which year the Diatto company introduced their successful Diatto Tipo 20, a 2-litre four with shaft-driven overhead camshaft, 4-speed gearbox, and the usual Italian mock-Rolls Royce radiator. Output, originally a modest 40bhp, was worked up to around 70 by Diatto’s development engineer, Alfieri Maserati. Competition successes included three successive victories by Diatto (1922, 1923 and 1924) in the Circuit of Garda, as well as the 2-litre honours in the 1924 Gran Premio Della Notte at Monza. The short-wheelbase high-performance Diatto 20S, as well as 4-wheel brakes, appeared in 1924 and at the end, in 1926 – 1927, 2.6-litre (Diatto Tipo 26) and 3-litre (Diatto Tipo 25 and 35) developments were listed, in addition to the basic model. Maserati built a dohc supercharged straight-8 Diatto for the 2-litre Grand Prix formula in 1925, but it made one brief and unsuccessful appearance. By 1926 the Diatto had been redesigned, and was being raced as the first car to bear the Maserati name.

Source: Georgano, encyclopedia of motorcar; MCS

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