Apart from development work on the 4.5-Iitre sports Maserati there is a great deal more experimental work going on at the Modena works, and by some careful design planning a very full programme combining sports cars and Grand Prix cars is being carried along in the same workshops. At the end of 1955 if was fairly obvious that the six-cylinder Grand Prix car was in need of revision, and for any serious long-term policy a new engine would be required for Grand Prix racing. 1956 saw a lot of drawing office work in progress and the beginning of 1957 has seen the results of the labours. First of all a V12 cylinder 2½-litre Grand Prix engine was designed and built, and this was arranged so that it would fit into the existing single-seater chassis in place of the six-cylinder engine. This new unit was tried out at Syracuse, and later at Monaco, though never actually raced, and on both occasions it was fitted to one of last year’s works 250F chassis frames. Bearing in mind that the near future is likely to see Grand Prix events insisting on the use of straight petrol instead of alcohol fuels, it was obviously time to start developing a Grand Prix engine to run on petrol. Combining the development with sports car racing, a 3½-litre version of the V12 cylinder Grand Prix engine was built, this having a bigger bore and stroke, though the outside dimensions of the engine were unaltered. Running on normal high-grade pump fuel this new engine developed 330 b.h.p. and was fitted to a modified 300S chassis frame. At the same time it was realised that the V12 Grand Prix engine was badly in need of a 5-speed gearbox in which all the ratios could be used. The original Grand Prix gearbox was a 4-speed and in 1955 this was modified to a 5-speed, with bottom gear used only for starting from rest. By May of this year a completely new gearbox had been built in which the first of the five speeds could be used at any time. The layout was exactly as used on all the Grand Prix cars and the 300S, which is to say that the gearbox was part of the rear axle/final-drive unit, but extending out to the right-hand side of the differential unit. The new 5-speed gearbox meant that the V12 engine would be able to maintain its full r.p.m. under all conditions, for the working range of the 2½-litre engine is 6-7,000 r.p.m. up to 9,700 r.p.m.
As an initial test for this new unit it was fitted to the modified 300S chassis into which the 3½-litre V12 engine was fitted, and Hans Herrmann drove it in the Mille Miglia. Due to the driver knocking a hole in the sump on a solid object the car did not get far, but it was enough to make it worth while fitting the new 5-speed gearbox into the V12 Grand Prix car and taking it to Monaco for practice. The 3½-litre sports car was again used, for practice at the Nurburgring before the 1,000 kilometres and so it can be seen that Maserati experimental work on Grand Prix cars for 1957 and the future is running hand-in-hand with experimental work for sports car racing. In addition the very large brakes built for the 4.5-litre sports car can be fitted to the normal 300S sports car, or to the experimental 3½-litre car. The knowledge gained from running the 3½-litre V12 engine on straight petrol can obviously be put to advantage if the Grand Prix engine has to use straight petrol, and also in the testing stage is a 2½-litre four-cylinder engine, for use in sports cars or Grand Prix cars, using straight petrol.
In steady but limited production are the two Gran Turismo Maserati models, the A6G200 which is the six-cylinder 2-litre fitted with various coupe bodies by Allemano, Zagato or Frua, and the new 3½-litre six-cylinder Gran Turismo car described in the May issue of Motor Sport. It will be appreciated from the foregoing that Officine Maserati have a pretty full development programme in hand, and though at times their activities may seem chaotic, beneath it all is some pretty careful planning and long-term development.
For the record the V12 cylinder Grand Prix engine has a bore and stroke of 68.5mm. by 56mm. giving a capacity of 2,500 c.c. and develops 310 b.h.p. at 9,700 r.p.m.; the experimental sports car 12-cylinder engine has dimensions of 73.8mm. by 68mm., giving 3,500-c.c. capacity and develops 330 b.h.p. at 7,700 r.p.m. and having seen both these engines on the test-bed developing these powers I can assure readers that they look and sound as impressive as they read. D.S.J.