We wouldn't blame you for never having heard of car makers such as Mason, Maxwell, Perry and Castro - but these very makers remain an important part of the history of many car manufacturers that remain in business today. And this is the case with Diatto, formerly of Turin.
Diatto was a railway engineering and iron-founding concern which entered the motor industry sometime between 1904 and 1907, building Clement-Bayards under licence. The company started out with high hopes: it had a six-model range consisting of 8 hp and 10 hp twins, and 12, 20, 35 and 50 hp fours.
Unfortunately, though, there was a recession in the Italian industry soon after Diatto had got under way, and savage cutbacks were necessary. By 1911 only one model, a 15.9 hp four, was being built; a half-hearted attempt to import this model into Britain was made, but lasted only a short while.
In fact, the marque's pre-war history was almost totally undistinguished, being relieved only by an eighth place in the 1914 Targa Florio for Rigoletti's car. In 1919, Gamboni's Diatto took third place in the same event, although this was completely over-shadowed by the antics of the winner, Andre Boillot, who crossed the finishing line backwards in his Peugeot.
Post-war models were a 10 hp and a 20 hp, both with four-cylinder engines, of 1.0 and 2.7 liters respectively. There was also a brief excursion into the manufacture of Bugatti Type 13s (like Rabag in Germany and Crossley in Britain), one of which won the 1921 Circuit of Brescia, from which the Type 13 took the name 'Brescia Bugatti'.
Thermosiphon Water Circulation
The little 10 hp was a far more modern design, with an 8.9 hp side-valve engine, featuring pressure lubrication, and a cow led fan to increase the efficiency of the thermosiphon water circulation.
For the 1923 season, Diatto announced a more exciting new model, the 15 hp four, using the 20 hp chassis, but with a 15.9 hp, single-overhead-camshaft, 2-liter engine of great potential, developing 52 bhp in standard guise. It appealed to the sporting market, and racing versions were soon in action.
The Maserati Brothers Tune The Diatto
Among the most effective tuners of the 15.9 hp Diatto were the Maserati brothers of Bologna. Alfieri Maserati had already driven a tuned overhead-camshaft 3-liter Diatto to a number of class wins; in 1924, he entered a modified 2-Iitre Diatto with twin overhead-camshafts for the Spanish San Sebastian Grand Prix, and made his way to third place before the engine gave out.
Its performance had been convincing enough for Diatto to commission the Maserati brothers to design a proper racing car in the shape of a straight-eight, 2-liter, GP model. It made only one appearance, at the 1926 Italian Grand Prix, where sheared blower bolts forced its retirement. Diatto, in deep financial trouble, gave the car to the Maseratis for further development work and withdrew from competition for the time being.
The 2 liter Short Wheelbase Super-Sports
The touring range was rationalised in 1923, when the 10 hp model was dropped, and production centred on the 2-liter Model 20 and its derivatives. The ambitious English importing operation collapsed and the agency passed to Cyril Durlacher of Upper St Martin's Lane, London. In 1924, a short-wheelbase Super-Sports 2-Iitre became available, with a lightened chassis on which semi-elliptical rear springs replaced the cantilevers; the 1924 London Show car was a real eyecatcher, with a two-seater body painted geranium red.
During the same period, the touring model gained a longer wheelbase and four-wheel brakes as standard. The 1925 range included another new model, the Model 35 3-liter, on the same chassis as the Model 30 2-Iitre Super-Sports, while the Model 20a 2-liter touring model continued virtually unchanged; the same range ran on for another four years before closing down, except for a couple of sporting interludes.
First, a handful of the straight-eight, GP-type cars were built as road-going sports cars, then in 1927 the four-cylinder, 5-liter 'M Special' was announced, although it seems to have been undistinguished. The Maserati brothers, however, had more success: the GP straight-eight Diatto - which was reborn as the 1500 cc Maserati.
The Death of Diatto - The Rise of Maserati
So as Diatto died, Maserati was in the ascendant. Had the 2-liter GP car been more successful and had Diatto been adequately financed, the course of motoring history might have been different. Maybe Diatto would now be a luxury marque and Maserati still a workshop in Bologna. But motoring history is full of "what if's?". And as the saying goes..."If your Aunty had balls, she would be your Uncle".