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THE MOST SUCCESSFUL MASERATI - the OSCA Mt4
by Stanley Nowak
If pride cometh before a fall, then the pride must be shared equallilby Ernesto, Bindo, and Ettore Maserati on the one hand and Adolfo and Omer Orsi on the other. Late in 1937, under the pressure of depression economics, the Maserati brothers sold their company and all rights to the use of the Maserati name to the wealthy Orsi family and stayed on under the terms of a 10 year employment contract. As the 1947 expiration date approached, neither the Orsis nor the Maseratis would bring up the subject and on the date the contract expired, the Maseratis left the Modena factory without a word of discussion on either side.
As quickly as possible, space was obtained in a corner of the original Maserati works in Bologna, where the brothers had started their business in 1926, and they set about designing a new car from a clean sheet of paper. The new company was christened 'Officine Specializzate Costruzioni Automobili - Fratelli Maserati SpA'. This 'office specializing in the construction of automobiles' created a new car called the OSCA and it launched the Maserati brothers into their greatest commercial success.
The youngest brother, Ernesto, shared with his oldest brother, Alfieri, a brilliant talent for engine design. When Alfieri died in 1934 Ernesto took on the full responsibility for leading his brothers, and Bindo and Ettore carried on with the supervision of the administrative and production side of the business. Their respect for each other was unquestioned and this enabled thern to work together with ease and efficiency.
Their goal was clear; to establish themselves with a winning car in the 1100 cc sports/racing category which was so very popular in Italy. Their design direction was inborn: simplify and lighten!
Nothing in their design was controversial or experimental and the most direct, simple economical solutions were always chosen. The same respectful approach was applied to the execution of the design and the very high standard of finish only served to enhance its simplicity. No Bugatti, Ferrari, or post-1947 Maserati was ever made to higher standards!
The O.S.C.A. model was called the Mt4 and over the next 8 years it was developed into the most successful under-1500 cc sports/racing car in the world. The chassis followed the lines of their A6GCS Maserati (the last model they designed before leaving the Maserati factory): a frame of 2½-inch tubes, at the front of which were attached upper and lower A-arms of unequal length with coil springs compressed from the bottom A-arms, a roll bar clamped to each of the top A-arms and telescopic shocks mounted just aft of and parallel to the coil springs. At the rear, half-elliptic leaf springs were slung below the live axle with telescopic shocks mounted vertically at each side.
Luigi Fagioli at the Bologna control in the 1950 Mille Miglia.
His remarkable 1100 cc OSCA finished Ist in Class and 7th
overall. (Chassis number unknown).
The first few OSCA Mt4s were cycle-fendered 2-seaters, utilizing an engine which was a 4-cylinder version of the single overhead camshaft 6-cylinder engine they had designed for the original version of the A6GCS Maserati. The bore and stroke was 70mm x 7lmm giving a swept volume of 1092 cc and was officially announced as producing 55 hp at 5500 rpm with a compression ratio of 8 to 1. This was most likely a smoke screen and contemporary estimates of 80 hp are certainly more accurate. A 1355 cc version developed 90 hp at 6000 rpm with a bore and stroke of 75min x 76mm.
In traditional Maserati fashion, the aluminium head was hand lapped to the aluminium block making a gasket totally unnecessary! Driven by chain from the crankshaft, the single overhead camshaft was mounted on the right side of the cylinder head and operated the intake valves by means of short -rockers;.the exhaust valves on the left side were opened via push rods running across the head to short rockers. This ingenious system permitted a hemispherical combustion chamber. The spark plugs were centrally mounted and accessible through tubes sealed'by exterior screw caps on the top of the valve cover. These water-tight caps admitted the ignition wires which ran a short distance from the distributor on the side of the block. The armature shaft of the generator powered the water pump and the entire assembly was belt driven from the front of the crankshaft. No fan was fitted. The crankshaft had 5 main bearings and was machined from a solid bille't. Every surface was superfinished and in company with the unusual machined and drilled flywheel was balanced statically and dynamically.
Luigi Fagioli in the twin cam 1100 cc OSCA at Monza.
This car carried him to his second Class win in the
1951 Mille Miglia. (Chassis number 1112)
Oil was fed at high pressure - over 125 Ibs. per square inch - and the beautifully finned magnesium sump was the only attempt at cooling the oil. The dry sump, scavenge pump, oil radiator, and oil tank of the A6GCS Maserati were discarded as unnecessary weight. Oil breathers were nowhere in sight; two vertical rectangular passages cast into the crankcase allowed oil capours to escape downwards through the sump. Two downdraft Weber carburettors fed four intake ports and exhaust gases passed out through four individual pipes.
From the tight fitting driver's seat of curved aluminium covered in multipleated leather, the view was enchanting. Instrumentation was minimal: one 8 inch 10,000 rpm tachometer, one water temperature gauge almost as large as the tachometer, and one small oil pressure gauge. The 4-spoke steering wheel was circled in wood and in the centre a small OSCA emblem was set into the horn button. The starter was a masterpiece of artful simplicity. One simply pulled on a lever, under the instrument panel, connected to a wire attached to the starter motor!
Over it all was an unadorned aluminium body just wide enough to admit an Italian driver and his mechanic. The wheels were barely covered by FIA dimensioned cycle fenders. The grill was almost circular and it established the shape that was to identify all racing OSCAs for the next 7 years.
It looks right! The beautiful 1500 MT-4 chassis ready for Morelli
carrozzeria. This is a late model MT-4 with twin plug head.
Ernesto's touch is clearly evident. This photo taken in late 1954.
The new Mt4 first appeared at Pescara on August 15th, 1948 in the hands of Franco Cornacchia. Its second and third appearances established it as a winner. On September 19th, 1948 Gigi Villoresi removed the cycle-fenders and finished first overall in the Formula II Grand Prix of Naples soundly beating all the Ferraris in the process! Dorino Serafini repeated the win at the Circuito del Garda on October 24th, 1948 again making light of the 2-litre Ferraris. A new Marque had been established and the Maserati brothers began filling orders.
In 1949 a double overhead camshaft head was put into production. The camshafts operate the valves via finger followers. This head was fitted to both the 1100 cc and 1300 cc versions. At the same time the rear suspension was altered and trailing ¼-elliptic springs replaced the ½-elliptics, thereby improving the roadholding.
By 1953 a 78min x 76mm 1453 cc version was introduced offering 110 bhp at 6200 rpm. A year later the final version of the Mt4 was introduced: this featured a twin ignition cylinder head with a special Marelli distributor driven off the idler gear between the two camshafts at the front of the head. A bore and stroke of 78mm x 78mm brought the engine size to 1490 cc with an announced horsepower of 110 (sic) lip at 6300 rpm. All of these horsepower figures are conservative. The Maserati brothers always preferred to understate their power claims, letting the cars performance speak for itself. For example, the 1490 cc twin ignition engines produced as much as 135 hp and this model frequently beat the 170 hp A6GCS Maserati!
By the end of 1951 Guilio Cabianca, Felice Bonnetto, and Luigi Fagioli had established the OSCA as the best sports/racing car in the world under 1500 cc. Fagioli won the 1100 cc class in both the 1950 and 1951 Mille Miglia. This cycle-fendered car was later sold to Rees Makins of Chicago, Illinois and was the first OSCA to arrive in the US. In its first race, the 1500 cc event at Bridgehampton in 1952, it won overall and defeated Max Hoffman's 1500 cc Glockler-Porsche. And all this with only 1100 cc!
Ernesto Maserati's classic MT-4 OSCA powerplant. The single
plug version was available in 1100, 1350, and 1450 cc models.
A unit similar to this carried Moss to his incredible Sebring victory in 1954.
In 1950 Bonetto finished first overall at the 1100 cc Gran Criterium. In 1951 Cabianca won the same event where other OSCAs finished second, third, and fifth. Early in 1952 Cabianca entered the same car (with full width coachwork), in the great Targa Florio and led this gruelling race against all opposition for seven laps out of the total ten before he was forced out with rear axle trouble. Later in 1952 this car was sold to American enthusiast Al Garthwaite. In 1953 it was sold to a suburban Philadelphia car dealer, Otto Linton, who campaigned it successfully until 1957! In 1954 he won Brynfan Tyddyn and finished 5th overall at Sebring. The overall winners were Stirling Moss and Bill Lloyd in Briggs Cunningham's 1453 cc OSCA which is now exhibited at Cunningharn's fine museum in Costa Mesa, California.
On the West Coast, writer AI Coppel bought Randy MacDougall's 1100 cc OSCA in 1953 and proceeded to engage in a series of races with Ken Miles in his famous M. G. Special. Bill David bought Bill Spear's 0SCA and the two gave the amazing Miles a very tough time. By vastly superior driving Miles barely won at Pebble Beach and March Air Force Base.
In the east Briggs Cunningharn won the 6 Hour Race at Mac Dill Air Force Base and Bob Said took first in George Moffett's OSCA at Bergstrom Air Force Base after wrecking the car in practice. Later in 1953 Said took another OSCA to Europe and won the first victory for an American in Europe since Jimmy Murphy took a Duesenberg to France in the 1920s. Phil Walters won the last race on Bridgehampton public roads beating Jim Pauley's Bandini and John von Neumann's Glockler-Porsche. At Le Mans Damonte's unique Vignale bodied coup6 won the 1100 cc class. OSCAs also won at Thompson, Sowega and Reno. 1953 was quite a year for the Maserati brothers.
Works driver Guilio Cabianca in the 1952 Mille Miglia where
his 1st in Class ranks as one of the great Mille Miglia drives.
This famous car was raced with both 1100 cc and 1350 cc
MT-4 engines. (Chassis number 1114)
The OSCAs continued to dominate American 1500 cc sports car racing in 1954. They won at MacDill and Hunter Air Force Bases, Pebble Beach, Golden Gate, Westover, Lockbourne, and Offutt Air Force Bases, Watkins Glen, Seafair, March Air Force Base and Akron. But the handwriting was on the wall when Bob Davies in a Porsche 550 Spyder defeated Briggs Cunningham in his favourite OSCA at Ft. Pierce.
Driven reasonably, with a rev limit of 6500 rpm, the OSCAs were good for up to 10 long races a year before an overhaul was required. Little was done between races except change oil and spark plugs, inspect the cams for wear and adjust the brakes. Tyre wear was minimal due to the car's low overall weight: 1650 lbs. ready to race. Amazingly tractable, they could even be driven to and from races on the road provided hotter plugs were used and the revs kept below 5000 rpm. Without a doubt the MO OSCAs were the most successful under 1500 cc sports/racing cars ever built!
Within the past two years collectors have begun to buy and restore these delightful Mt4 OSCAs and they have learned that the workmanship throughout is superior to that found in Ferraris and Maseratis of the same era. Five Mt4s, a JN (1500 cc), and a 187N (750 cc), are currently being raced in Vintage sports Car Club of America events in the North East. They are surprisingly fast and have frequently beaten or equalled the times of much larger cars. My own 1490 cc twin ignition car has been timed in the standing start 1 mile at 16.0 seconds!
About 70 Mt4s were built and at least 20 were brought to the US. Only 12 have been located and very few are for sale. If you can find an Mt4 for sale, buy it. A large supply of new and used Mt4 parts has been put together in the North East and this will allow these fine cars to be run competitively for many years to come. I can assure you that the purchase of an Mt4 OSCA will be the best and most enjoyable investment you evet made.
Turin chemist Dott. Damonte commissioned Vignale to create
this wild Le Mans coupé on the MT-4 chassis. Driven at Le Mans
in 1952 and 1953, it won its class at record speed in 1953.
(Chassis number 1120)
This article first appeared in the Spring 1974 issue of Trident
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