Racing car development

When the BMW 328 sports car was introduced to Great Britain in 1936 it created quite a stir, for here was a very civilised 2-litre car that could be used for everything from shopping to Brooklands racing. Its six-cylinder push-rod engine used an ingenious valve gear in which inclined overhead valves were operated from a single side-mounted camshaft by means of rockers and transverse pushrods as well as the orthodox vertical pushrods. This gave all the advantages of two overhead camshafts without any of the usual complications of camshaft drives. To launch the new model the concessionaires ran a slightly tuned pre-production model at Brooklands where it covered 102 miles in one hour. As sold in strict production form the 328 was capable of 95 m.p.h., but with a few optional extras it was good for nearly 110 m.p.h. and racing versions could be developed to reach 125 m.p.h. One customer repeated the hour run at Brooklands with her car and put 105 miles into the hour and H. J. Aldington covered 107 miles in one hour at an MCC High Speed trial.

The car featured here is GHX 516, a normal production BMW 328 purchased new in 1937 by Leslie Johnson and was noted for the way he used it for every imaginable type of sport during 1938/39. It ran in sprints, hill-climbs and circuit races all over the country, and also in rallies and off-road trials, always running fully-equipped as illustrated and always driven to the meeting. L. G. Johnson (BMW) was a familiar name in the awards list and the 328 was recognised as being a remarkable all-rounder. While competitors with other cars stripped all the road equipment off at hill-climbs and sprints, the 328 owner left everything in place and merely folded the windscreen flat, or as in the photograph of GHX 516 at Prescott, only one half of the windscreen.

In 1946 when sprints and hillclimbs resumed after the war, an enthusiast in North London, Oscar Moore, acquired a 328 and was so pleased with it that he soon acquired a better one. This was GHX 516 and Moore used it in a number of race meetings in Europe. Searching for more performance the car was totally rebuilt with light weight as the keynote, for the basic 328 was pretty light to start with. An alloy body of minimum proportions was built and small cycle-type mudguards were used and major items such as the wheels were replaced by special light alloy ones.

At this time Formula B (which subsequently became Formula 2) was under way, for cars of 2 litres capacity and Moore felt that the 328 BMW had a lot of potential for this category no during the winter of 1947/48 GHX 516 underwent another change. It was transformed into a pure single-seater racing car, as shown in the lower photograph on this page, and became the OBM, these being Moore's initials. The steering was moved towards the centre-line of the car, a fuel tank occupied the space alongside the driver, many steel parts were replaced by alloy components manufactured by Moore's friend Ron Willis, the spring rates were revised as were the shock-absorbers; gearbox and axle ratios were altered and the engine was developed to run on a mixture of methanol, benzol, acetone, and nitro-benzine, which was quite an exciting smelling brew. Wheels and brakes all received attention and the magnesium-alloy wheels weighed 8 lbs each, compared to the 21 lbs of the standard steel wheel. When all the modifications were finished a light alloy single-seater body was built and the original production BMW 328 had now gone for ever and in its place stood the OBM.

During 1949 Oscar Moore raced the car extensively all over Europe, in Belgium, France and Italy and was well-pleased with the conversion and though it was no match for Formula B cars from Ferrari or Gordini, it gave the owner the opportunity for a lot of real motor racing on European road circuits. All that was available in England was racing on disused airfields, which did not appeal to Oscar Moore. When Moore gave up Formula B racing and turned to big-engined sports car racing the OBM was sold and in the passage of time has disappeared, unless some reader has it hidden away in a lock-up garage. — D.S.J.