The Testadoro brand was given to a special cylinder head for engines (originally Fiat 508 “Balilla”) designed by the engineer Arnaldo Roselli at the end of the 1930s. The term "Testadoro" was coined due to the characteristic color of the head itself, originally cast in bronze. Following the meeting with Giorgio Giusti, an entrepreneur from Turin, the cylinder head was also produced for the more popular Fiat 500 called "Topolino", which allowed the manufacturers a greater diffusion of the product, and the owners of the very popular Turin car an increase in power. combined, according to the advertising of the time, to a decrease in consumption. It must be remembered, in fact, that the standard “Topolino” was credited with only 13 HP at the time, which made it slow and awkward despite its very light construction. The “Testadoro was available in three different versions, differing in compression ratio, power and use:“ N-Normale ”; “S-Sport” and “C-Corsa”.

Giorgio Giusti

An entrepreneur from Turin, Giusti was in 1935, together with Giorgio Ambrosini, one of the animators of the Scuderia Subalpina founded by Count Luigi della Chiesa. The team then served as Maserati's official team. Following the meeting with Roselli, then under the Scuderia Ferrari, Giusti proposed the mass production and marketing of the Testadoro for the Fiat 500 through his own company, the Casa dell'Auto di Torino. After three intense years of racing and victories, including racing himself as a driver of his cars, Giusti retired from racing in 1949 following the death of his partner Roselli, which took place in the autumn of that same year.

Arnaldo Roselli

Engineer, formerly employed by Scuderia Ferrari, was in 1935 among the designers (together with Luigi Bezzi and Enrico Bertacchini) of the infamous twin-engine Alfa Romeo 16C, commissioned by Enzo Ferrari to counter the dominance of German cars in the Grand Prix of epoch. Roselli personally designed a cylinder head with hemispherical combustion chambers and radial valves for the transformation of normal Fiat 1100 A engines into racing engines for the Sport 1100 class. Following the entry into partnership with Giorgio Giusti, he designed the cylinder head with 750cc for the transformation of the quiet Fiat 500 engines. He died in the autumn of 1949 in a car accident together with Dante Spreafico, a driver with several Mille Miglia behind him.

Evolution of the “Testadoro”

1947

The first version of the Testadoro for the Fiat 500 was cast in bronze and brought the displacement of the original crankcase to 660cc. According to the designer, the use of bronze alloy served to increase rigidity and its better thermal conductivity, characteristics that should have ensured greater reliability over time due to less deformation at high temperatures. The burst chambers were perfectly hemispherical, with the candles arranged in a 90 ° V shape and the candles in the center. This solution, which until then had been characteristic of racing cars, allowed a larger size of the valves and better combustion of the air / petrol mixture. The valves were always controlled by the camshaft placed in the original fiat crankcase, by means of rods, rockers and special transmissions. The compression ratio was 6.2 for the “Normal” version and 7.2 for the “Sport” version. The diameters of the valves varied according to the version. This version of the Testadoro engine, still with the original Fiat crankcase, was used on the first complete Testadoro cars, the “Sport” and the “Drin Drin”.

1948

For 1948 the "Testadoro" lost its characteristic color, as the casting passed from the original bronze to aluminum. The cylinder head was, however, immediately recognizable by the classic color of the valve cover, which bore the words “Testadoro” and “Casaauto - Torino” in relief. 1948 also saw the creation of a completely in-house engine, abandoning the Fiat crankcase for a new cast iron casting with three bench supports, which had in common with the original only the cylinder center distance of 61mm (to maintain the compatibility with the head). The engine was completed by a new shaft in chrome-nickel steel with a stroke of 78, which combined with a bore of 55 brought the total displacement of the 4-cylinder to 742cc, thus coming very close to the maximum displacement limit to compete in the class. 750 sport. With a compression ratio of 9: 1, this new complete engine developed an output of 45 hp at 6,500 rpm.

1949

For the 1949 racing season, the Testadoro engine developed in 1948 was updated with the steel cylinder liners subjected to nitriding treatment. This engine, the maximum expression of the development of the Testadoro, produced 48 HP at over 7,000 rpm, and was combined with a 5-speed gearbox. Testadoro 1100 Although produced in smaller numbers than the more popular cylinder head for the Fiat 500, the Testadoro 1100 was used in some prestigious cars built at the turn of 1950: the Fiat 1100 Rovelli bodied by Castagna (with an innovative removable hard-top) and the Revelli -Monaco Testadoro 1100, designed by the famous designer Mario Revelli of Beaumont. A Testadoro 1100 barchetta car was being planned for the 1950 season (when the change in the regulations of the "Sport" classes prohibited open-wheel cars), but which never saw the light due to the cessation of Giusti's activities in the field of car competitions.

Complete Testadoro racing cars

Testadoro Sport

The Sport was the first car produced under the Testadoro brand, in 1947. It had an original Fiat engine, obviously equipped with the cylinder head which was the specialty of the car manufacturer in the 660cc version. The chassis was also the original one of the "Topolino", although updated and "lowered", according to the advertisements of the time. Equipped with a particular "boat" bodywork decorated with abundant air intakes both in the front and in the side view, the "Sport" participated in various races, including the Varese Circuit in 1947.

Testadoro Drin Drin

Also in 1947, Giusti he built a second "boat" with the same technical base as the "Sport". The distinctive name of the car, according to Andrea Curami, seems to be due to the nickname of Giusti's wife, Andreina. This time the design of the car was entrusted to the expert hands of Zagato, who designed a car characterized by extreme clean lines. According to the chronicles of the time, the Drin Drin won a race in Montlhéry (France) and obtained numerous good placings.

Testadoro Marinella

Obviously dissatisfied with the Topolino chassis still used in previous cars, for the 1948 car Giusti turned to his friend Enrico Nardi to have a tubular chassis, built like many others by Gilberto Colombo, founder of Gilco. The Marinella also had a suspension department worthy of higher class cars, with the front with deformable wishbone and coil springs, when many of the competitors had the classic transverse leaf spring. The Marinella was built in a "Siluro" style by Zagato, with the "open" wheels characteristic of those years, with a tapered shape that followed the design of the frame. The car was obviously equipped with the new complete Testadoro engine of 742 cc and 45 horsepower, and was built according to many sources in 9 specimens, making it one of the most popular ready-to-run models of the time. With this car Giusti himself had excellent results in numerous races, in which he managed to get the better of cars with a much larger displacement but a more antiquated general concept. The best result of the season was Giusti's victory in the “Michelin Cup” held on the historic Valentino circuit in Turin.

Testadoro Marinella Hard-Top

The torpedo-shaped cars were fast and easy to handle, perfect for closed or city circuits. For endurance races, on the other hand, the drivers increasingly preferred to have shelter from the elements. Probably to meet these needs, a single example of Marinella was prepared in the “barchetta” version and equipped with an original removable “hard Top” to be used in longer races, such as the Mille Miglia and the Targa Florio. The car was officially presented in the Zagato stand at the first “Italian bodywork exhibition” in Milan in November 1947. A valuable photograph of this stand is in the archive of the Turin Automobile Museum. On this car the young Elio Zagato also attempted a sporting career at the Targa Florio in 1949, paired with the “official” driver of the “Squadra Testadoro” Ugo Puma. According to the book by Andrea Curami, this crew wins the "sport up to 750cc" class of the prestigious Sicilian race, in that year also valid as the "Giro di Sicilia", with race number 122. The same car appears to be registered in the Mille Miles of the same year with the crew Ugo Puma - Aquilino Branca, with the race number 234.

Testadoro Daniela

The Daniela (name of Giusti's second child) is considered the maximum development reached by Testadoro as a racing car manufacturer. Presented in 1949, it had the improvements made for that season to the engine (742cc and 48 horsepower at 7,000 rpm), a new Isorigid chassis produced by Gilco and a bodywork (always “two-seater torpedo”) also designed by Zagato. The Giusti / Colombo / Zagato trio produced a highly competitive car appreciated by both the press and the "gentlemen drivers" of the time. Dante Giacosa, Elio Zagato, Nino Farina and Carlo Biscaretti di Ruffia were present to testify the importance of the car, as confirmed by some photographs preserved in the archive of the Turin Automobile Museum. To testify the goodness of the project were the numerous victories collected in 1949, among which the Gran Criterium 750 of Monza on June 26 (absolute victory for Daniela No. 8 of Mejnardi). Among the other drivers of the “Testadoro Team” participating (Ugo Puma, Antonio Stagnoli, Aquilino Branca) stands out the name of Nuccio Bertone with the number 14. Another important victory for Daniela in 1949 was that at the Senigallia circuit, obtained by Ugo Puma.

The retirement from racing and derived cars

the retirement from racing decided by Giusti due to the aforementioned fatal accident of Roselli, the official contribution of the house to customers ceased. Given the goodness of the general design and the rarity of engine spare parts, many cars continued their sporting activity with a new power unit. Andrea Curami, in his volume “sport and its artisans” mentions in particular the Marinella and Daniela made by Giusti's good friend and pilot Aquilino Branca with a twin-shaft Moretti engine, and the GI-CO Giannini G1 built by Armando Pasqualin on a Daniela basis. Special Testadoro cars Several original creations based on Testadoro are known, including the Zagato Fiat 500 Testadoro presented at the Turin motor show in 1947, the Fiat 1100 Rovelli with bodywork by Castagna and the Revelli-Monaco Testadoro 1100, designed by the famous designer Mario Revelli of Beaumont.

Curiosity

The Testadoro has the curiosity to have been a car driven by three illustrious protagonists of Italian automotive design: Mario Revelli of Beaumont, Elio Zagato and Nuccio Bertone.