Engineering:O.S.C.A. MT-4

1955 OSCA MT4

The O.S.C.A. MT-4, also spelled the OSCA MT-4, or the Osca MT-4, is an Italian sports car prototype, designed, developed, and made by Officine Specializzata Costruzioni Automobili, between 1948 and 1956, but was raced and used in active competition until 1966. Between 1948 and 1966, it managed to rack up an incredible win tally of 92 wins, 109 class wins, 9 pole positions, and managed to clinch 194 podiums; an amazing record indeed.

History and development

The Osca MT4 is a vehicle concept that is unusual in motorsport history. Due to the variety of engines used with different displacement sizes and a large number of chassis built, the vehicle had a long service life as an emergency vehicle. This resulted in a remarkable success story for the racing car model.

In 1937, five years after Alfieri's death, Ettore and Ernesto Maserati were forced to sell Maserati after financial turmoil. However, the contract with the new Maserati owner Adolfo Orsi included a further ten-year bond between the brothers and their former company. In 1947, Officine Specializzata Costruzioni Automobili Fratelli Maserati was founded and the first vehicle type, the MT4, was built. In its original form, the chassis and engine were based on the Maserati Tipo 4CL, first built in 1939. The 4CL was actually a single-seater racing car, which in the early 1950s was still in its infant formula 1 World Championship was driven. A chassis, 1565, was streamlined, used in record runs, and driven by Luigi Villoresi in the 1939 Gran Premio di Tripoli.

Development of the MT4 began in 1948 using plans and parts from the 4CL. In all, OSCA built 77 chassis between 1949 and 1956. All engines fitted to the MT4 were aluminum block and in-line 4 cylinders. The bore and stroke have changed over the years. The displacement of the engines increased from 1090 cm³, over 1290 cm³, 1340 cm³, 1450 cm³, 1490 cm³ up to 1492 cm³. The four-speed quick-shift gearbox was also an in-house design.

O.S.C.A.'s first automobile was the MT4, for Maserati Tipo 4 cilindri. The 1,092 cc engine, which produced (72 PS (53 kW; 71 hp) at 6,000 rpm, had a in-house designed block, alloy head, and the bodywork was built as a two-seater barchetta. The MT4 first raced in 1948 at the Pescara Circuit and the Grand Prix of Naples, where it was driven to a win by Luigi Villoresi. The engine was modified to 1,342 cc capacity (with 90 PS (66 kW; 89 hp) at 5,500 rpm) in 1949.

OSCA only supplied the chassis, the bodies were manufactured by Italian bodywork companies. That is why there were sometimes major differences in the exterior shape, which were mainly due to special customer requests. Therefore, none of the carriages that have been preserved is exactly the same as the other. The MT4 was a sales success and this is one of the main reasons why it was built for so long.

In 1950, a new DOHC (MT4-2AD) raised power to a maximum of 100 PS (74 kW; 99 hp) at 6,300 rpm, and in 1953 the engine was enlarged to 1,453 cc, producing 110 PS (81 kW; 108 hp) at 6,200 rpm. The all new tipo 372 DS twin spark engine with 1,491 cc, which produced 120 PS (88 kW; 118 hp) at 6,300 rpm, was later used in the O.S.C.A. MT4 TN (for Tipo Nuovo, "new model") of 1955. With this new engine, the car received the new name FS 372, of which five were built. One of these belongs to Sir Stirling Moss, who raced it in historic races across the globe until his retirement in 2011. Versions of this engine went on to be used in coupé and convertible models of regular Fiats from 1959 to 1966.

These automobiles were mainly barchettas, but a few were built as berlinetta bodies by Pietro Frua and Vignale. A Vignale bodied MT4 Berlinetta won in the 1,100 cc class at the 1953 24 Hours of Le Mans.

The 1954 12 Hours of Sebring was won by drivers Stirling Moss and Bill Lloyd in an O.S.C.A. MT4 as part of the Briggs Cunningham Team. In the April 6, 1992 issue of AutoWeek, Cunningham stated that, of all the automobiles he built, owned, and raced, O.S.C.A. was his favorite racecar.

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  OSCA MT4 Morelli Spider 1955

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  First-generation OSCA MT4 from 1949

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  OSCA MT4 at Donington Park

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  1954 OSCA MT4 1500

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  1952 OSCA MT4 MM Spider

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  1949 OSCA MT4 'Siluro'

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  Le Mans winning MT4 Vignale Berlinetta

Racing history

The starts and racing successes of the MT4 are extensive and go beyond the usual framework of sports car models: 449 entries, 939 race starts, 81 overall, and 98 class victories.

The first use of an MT4 was in 1948 in a sports car race in Pescara. Driving chassis 1101 was Franco Cornacchia, who failed to finish the race. Victory in this event went to Giovanni Bracco and Alberto Ascari, who piloted a factory Maserati A6GCS to overall victory. The first finish was almost half a year later at the Targa Florio 1949, where Cornacchia finished 15th overall. The first successes followed in the same year. Giulio Cabianca won a sports car in Ferrara and three weeks later a race in Tigullio. The Giro delle Calabria won Dorino Serafini and Alberico Cacciari before Luigi Fagioli, who also drove an MT4.

From 1950 onwards, the MT4 established itself as a fast racing car that was not prone to defects and was hard to beat in the racing classes with displacements of less than 2 liters. At the Mille Miglia in 1951, Luigi Fagioli won the class for sports cars with displacements of up to 1.1 liters. In the overall standings, he finished eighth, just under an hour behind the winner Villoresi in the Ferrari 340 America Berlinetta Vignale. Cabianca repeated the class win in 1952. In the same year, the model was driven for the first time in the 24 Hours of Le Mans. Mario Damonte and a French racing driver using the pseudonym Martial drove one by Vignalebodied 1.3-liter MT4. Failure after 19 hours of driving due to clutch damage.

With the start of the sports car world championship in 1953, MT4s were of course also used there. After countless successes at national races in Europe and the United States, 1954 saw the greatest international success for an MT4. At the 12 Hours of Sebring, Stirling Moss and Bill Lloyd won the general classification for Briggs Cunningham's team. To date, it is the only overall victory for a sports car with a displacement of fewer than 1.5 liters in this long-distance race.

The light and maneuverable racing cars were often on a par with the high-capacity cars, especially on narrow and winding courses. This was evident, for example, at the 1956 Mille Miglia, where Cabianca and Umberto Maglioli fought for the lead in the early stages of the race with the Ferrari and Maserati works drivers. Gianfranco Stanga celebrated the last race victory with an MT4 at the Campagnana Vallelunga in 1961. The last known use outside of historical races was in 1966 in the sports car world championship. Giuseppe Rossi was at the Mugello 500 km race, finishing 38th overall and winning the racing class for prototypes with a displacement of up to 2 liters.