O.S.C.A. MT4 1950-1952

Mille Miglia cars

The OSCA MT4, also spelled the O.S.C.A. MT4 or Osca MT4, 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.

Due to the variety of engines of different displacement sizes and the comparatively large number of chassis built (thanks to strong sales), the OSCA MT4 had an unusually long service life for a competition car. Between 1948 and 1966, it notched 92 wins, 109 class wins, 9 pole positions, and 194 podiums an impressive record for a small manufacturer without the means of sustaining a factory competition effort.

Ernesto (seated) and Bindo Maserati in an early MT4 chassis in April 1948.

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 meant that the brothers had to remain with their former company for a ten-year term. In 1947 they were finally free to go their own way; 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 single-seater racing car, first built in 1939. Development of the MT4 began immediately, using plans and parts from the Maserati 4CL. In all, OSCA built 77 chassis between 1949 and 1956 (some sources state 72, some 78).

OSCA's first automobile was the MT4, for Maserati Tipo 4 cilindri. The initial cars used a Fiat 1100 block and the engine developed 55 hp (40 kW). OSCA soon developed a new 1,092 cc engine, which produced 72 PS (53 kW; 71 hp) at 6,000 rpm, had a in-house designed aluminium block and alloy head. Some sources state that 9 cars were built with 1.1-liter engines. Originally a single-cam design, in 1950 this was changed to a twin-cam unit, indicated by using the name MT4-2AD, with "2AD" signifying 2 Alberi di Distribuzione (twin camshafts). The 2AD was originally available as an 1100 or a 1350. The bore and stroke changed over the years and to allow competing in various classes, meaning that the displacement of the engines increased from 1092 cc via 1342 cc and then 1453 cc until finally reaching 1492 cc. The four-speed quick-shift gearbox was also an in-house design. The bodywork on early models was a two-seater roadster with or without cycle fenders, lights, and the various other accoutrements required to make it street legal. OSCA only supplied the chassis; the bodies were manufactured by Italian bodywork companies (or in some cases, by the buyers themselves) to the requirements of the individual buyers. Modifications and changes to keep cars competitive or due to changes in taste means that few preserved cars look much like each other.

While the original barchetta design was factory built, coachworkers such as Morelli, Moho, Vignale, and Pietro Frua soon supplanted the in-house design. In addition to the barchettas, a few examples were built with berlinetta bodies by Frua and Vignale. A Vignale-bodied MT4 Berlinetta won in the 1,100 cc class at the 1953 24 Hours of Le Mans.

In 1949 the engine was enlarged to 1,342 cc, with power increasing to 80–90 hp (59–66 kW) at 5,500 rpm depending on the tune specified. In 1950, the new DOHC (MT4-2AD) raised power to a maximum of 100 hp (74 kW) at 6,300 rpm for the 1350 engine, and in 1953 the engine was enlarged to 1,453 cc to compete in the 1500 cc class, producing 110 hp (81 kW) at 6,200 rpm. In 1954, this was bored out to a square 78 mm × 78 mm (3.07 in × 3.07 in) for 1,491 cc and fitted with twin sparkplugs. This "proper" 1500 engine produced 120 hp (88 kW) at 6,300 rpm and was aimed directly at the Porsche 550.^[14] The bore and stroke of the 1500 engine are the same as those of the Maserati 4CL, also developed by the Maserati brothers.

In a period road test, Road & Track got a MT4-2AD 1500 (chassis number 1148) to reach 120 mph (193 km/h) in spite of having been fitted with the lowest gearing, while doing the 0–60 mph (0–97 km/h) sprint in 7.0 seconds. The listed price was $10,000, enough to buy three V8-engined Ford Thunderbirds with a good margin, but on the other Road & Track stated that the OSCA had outperformed every lower-priced car ever tested by them. The reviewers also remarked on the rarity of an Italian-made car matching the manufacturer's claimed top speed, acceleration, and weight figures. The trunk on this example did meet the requirements for competition but mainly housed a spare tire and a 20-US-gallon (76 L) fuel tank. By this time, about half of OSCA's production was earmarked for the United States, with another ten percent being exported elsewhere.

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  1949 OSCA MT4 'Siluro'
 
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  1952 OSCA MT4 MM Spider
 
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  Le Mans class winner MT4 Vignale Berlinetta
 
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  1954 OSCA MT4 1450 Spider by Vignale (fitted with a 1500 engine)
 
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  OSCA MT4 Morelli Spider 1955
 
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  The OSCA twin cam engine
 
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  1955 MT4 1500 Coupé by Vignale, one of a handful of MT4 berlinettas

The OSCA MT4 is best known for the 1954 12 Hours of Sebring, where it won outright against much more powerful cars with drivers Stirling Moss and Bill Lloyd 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, the OSCA was his favorite racecar.