The old must give way to the new. The Maserati A6GCM had been quite successful in its first couple of seasons. However, part of its design was based upon the last efforts of the Maserati brothers themselves. It was time for an all-new design.
All-through the 1952 season, Gioacchino had been busy creating an evolution of the A6GCM that would be even more competitive, but that would also be in a position to adhere to the new rules for Formula One, once the governing-body decided on what those new regulations would entail.
The new design would bear some resemblance to the dominant Ferrari 500, but it would end up serving as the basis for Maserati's own dominant chassis in the very near future. However, to create the future dominant chassis, Colombo had to make a few adjustments to the A6GCM in order to find out the optimal design.
The chassis would retain the tubular structure with its longitudinal and cross members to stiffness and rigidity. Nevertheless, the new frame would end up featuring a longer wheelbase than the 1952 derivative. The wheelbase was extended from 2280mm to 2310mm. In addition, the car would also have narrower tracks at both the front and the rear of the car.
Colombo knew, since he headed up the revision of the in-line 6-cylinder engine, that he would have a bigger, more-powerful engine at his disposal for use in the A6GCM. However, this required some special emphasis when it came to the design of the new chassis. The bigger engine would cause greater torsion on the chassis. Therefore, using a trellis structure, Colombo was able to add the torsion resistance that was necessary to competitively handle the new engine.
The extended wheelbase helped to serve as the foundation for Colombo's all-new design. Some of the most obvious changes from the first model A6GCM became apparent right at the very front of the car, and they are partly the result of the extended wheelbase.
Gone was the 4CLT/48's nose design. Instead, Colombo would go with an oval, open-mouth radiator opening. This oval design served to also change the overall design of the chassis. The 4CLT/48, which also used an in-line engine, featured a wide tubular-frame bottom. The line of the bodywork then drew inward and upward to curve over the top of the engine. This would change on the A6GCM 'Interim'.
Because the nose on the first A6GCM followed the 4CLT/48's nose design and swept backward, and over, the in-line engine the bodywork had to be design as it were with a wider base drawn in to make a narrower, greatly contoured piece of bodywork over the top of the engine. The nose design changed on the second generation of the A6GCM.
Besides just the elliptical radiator opening, from the side, the nose appeared blunt. This meant that instead of the bodywork sweeping upward and backward it was, essentially, directed forward. This, and the longer wheelbase, enabled Colombo to design a slightly wider and flatter nose similar to that of the Ferrari 500. This elliptical bodywork, because the wheelbase was longer, was able to gently sweep upward and over the engine. This meant the nose of the car remained rather low and wide. This helped to give the car a much wider and lower look to its design although the car had actually been made more-narrow.
At each corner of the car the tire sizes were increased on the newer evolution of the A6GCM. The wheels would go from 4x15 to 5x16 tires. This would further help to improve the overall handling of the new Maserati.
Another performance improvement on the later evolution of the A6GCM concerned the brakes. Because of the larger wheel and tires size used the brakes would also be increased in size. This would help to increase the braking power of the car. To help with the cooling of the drums, deeper fins would be machined into the drum housing.
The front suspension would go through only minor alternations. Although rather happy with the front suspension, Colombo would design the new chassis with a shroud that would attach to the side of the chassis and that would wrap over the top and the bottom of the suspension members. This aided to provide the airflow with a rather smooth surface in which to flow around. This helped to slightly reduce drag and instability in this area of the car.
Because of the in-line engine, the exhausts for the engine's cylinders still exited out of the side of the chassis, rather high. On the driver's right-hand side attached the rounded cowling that covered the induction pipes. Out of the left side of the car, the exhaust pipes would protrude and run down along the side of the car and right past the driver in the cockpit. The long exhaust pipes then extended all the way to the very tail-end of the car. A heat shroud was attached to the top of the dual exhaust pipes, and very necessary, as the driver's left arm was located extremely close on the 'Interim'.
The new chassis, larger tires and brakes and the improved, more-rigid, chassis were all the result of building a car around an even shorter-stroke 1960cc in-line, 6-cylinder engine. By shortening the stroke and increasing the revs even more, Colombo, and his team, were able to increase the horsepower to 197hp. This was made possible by the increasing of the rpms of the engine. The new evolution would be capable of turning at 8,000 rpms. This was an increase of 700 rpms.
Although increased in weight up to 1258 pounds, the new, powerful, engine made it possible for the 'Interim' evolution to reach speeds well in excess of the 155 mph and could go from zero to 60 in less than seven seconds; 6.7 to be exact. This kind of performance made it possible for the new chassis to cover a kilometer in 26.5 seconds while touching speeds in excess of the 121 mph! In spite of the increased performance, Colombo and Massimino would elect to retain the same 4-speed manual gearbox used with its predecessor.
The rear suspension needed to go through an upgrade on the 'Interim' chassis. Throughout the 1952 season, there were moments when the rear axle on the A6GCM would fail on the car, thereby ruining a chance at a good result. It happened enough that Maserati knew they had a problem they needed to address, especially with the increased performance seemingly promised by the more-powerful engine, larger tires and brakes. The axle couldn't merely handle the car. It needed to be able to handle the car and the competition Ferrari posed. Therefore, the rear axle would end up being anchored to the frame, and would be done so using reaction bars and a seven-leaf, semi-cantilevered leaf spring.
Complete with its new shoes and bigger heart, the Maserati A6GCM 'Interim' was an all-new car, not just a stop-gap measure. It would end up proving to such a good 'Interim' measure that when the new regulations were established for the 1954 season many teams would just purchase an A6GCM and have it converted into the 250F. The reason for this became overwhelmingly obvious during the 1953 season.
The main highlight the A6GCM had managed to garner during the 1952 season would be a 2nd place at the Italian Grand Prix, which was the eighth round of the World Championship and one of the last races of the year.
In 1953, the 'Interim' made its presence known right away. Jose Froilan Gonzalez would score a 3rd place result in its first race of the season, the 1st Gran Premio de la Re. Argentina in January of 1953.
Overall, the 'Interim' would go on to earn seventeen podium finishes. Among those seventeen, five would be victories.
Some of the highlights from 1953 included a 2nd and 3rd place result at the French Grand Prix by Juan Manuel Fangio and Jose Froilan Gonzalez, a victory at the Italian Grand Prix and Modena Grand Prix by Fangio. Emmanuel de Graffenried, a privateer entry mostly, would go on to win three races just by himself. Those victories would include the 3rd Gran Premio di Siracusa, the 5th Lavant Cup race at Goodwood and the 17th Internationales ADAC Eifelrennen.
Armed with the new A6GCM chassis, Juan Manuel Fangio would go on to finish 2nd in the World Drivers' Championship in 1953. Jose Froilan Gonzalez, another Maserati pilot, would end up 6th in the standings. There would end up being another three A6GCM drivers that would end up inside the top-eleven in the standings by the end of the season.
Colombo new he had a winning design. All he needed to do was make the necessary adjustments to the chassis for the upcoming Formula One season in 1954. The 'Interim' would help break forth the dawn of the all-conquering 250F.
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By Jeremy McMullen
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