BMW 328 Roadster (1937-1940)

Although the BMW 328 was developed on the basis of the BMW 319/1, the car differed significantly in both its exterior appearance and under the skin. The lack of resources for an all-new design meant that the BMW 328 had to do with a modified version of the 50 hp engine from the BMW 326. The 2-litre grey cast iron block was given a new cylinder head (made from an aluminium alloy) with valves arranged in a “V”. Valves were controlled by the side-mounted camshaft using bell cranks on the exhaust side and transverse pushrods. This impressively effective upgrade increased output to 80 hp at 4500 revs per minute.

The early outings with the BMW 328 prototypes on the race track showed design engineers Fiedler and Schleicher that further development work was required for the 328 – when it came to use both on the road and in race action. The series-produced BMW 328 benefited from discoveries made on the race track in the form of a strengthened gearbox and rear axles. But it wasn’t only the modified drivetrain that made a convincing impression. The lightweigth construction, a design principle that was introduced with the BMW 303, made it possible to achieve higher average speeds and excellent handling characteristics, which very few car could match at the time.

The tubular frame construction developed by engineer Fritz Fiedler and patented by BMW played an important role in limiting the weight of the BMW 328 to 780 kilos. This frame consisted of two longitudinal tubes with circular cross sections which converged in an “A” shape from the rear wheels to the front of the car, accommodating the width of the engine, and were connected by rectangular profiles. The strong, lightweight frame supported the front suspension with lower wishbones and an upper transverse leaf spring, while the live rear axle had semi-elliptical longitudinal leaf springs. The tube cross sections then tapered towards the areas at the rear subject to lower bending forces, helping to significantly reduce the weight of the frame. This special tube design also led to improved bending resistance and torsional rigidity – and therefore gave the car better and more direct handling. A chassis with a tubular frame therefore had huge advantages over constructions featuring the U-section frame more common at the time.

The first three prototypes had no doors, and neither did they come with a mount or recess at the rear for the spare wheel. Their windscreen was low and single-piece in design. By contrast, the later series-produced cars had screens consisting of two halves – angled in a V – which could be folded down individually and had a wiper each. In addition, the BMW 328 came as standard with patented central-locking Kronprinz disc wheels with 5.25×16 tyres. Behind them, hydraulic brakes with 280 mm diameter drums gave good stopping distances for the time. A particularly sporty touch was provided by the two leather belts strapped over the bonnet. Along with the classic “double-kidney” design of the radiator grille, these light-brown cowhide belts – held in place by a clip-lock – represented a prominent stylistic element of the BMW 328.

When it came to getting into your seat, the BMW 328 first required you to reach inside the car, as the doors had no exterior handles. Once settled in behind the wheel you were greeted by a pair of pleasantly clear dials – the rev counter on the left and to its right a 180 km/h speedometer of equal diameter. These were joined by three smaller instruments charged with keeping the driver informed of fuel levels, oil pressure and water temperature. The usual buttons and switches for the starter motor, lights, choke and direction indicators rounded off the dashboard.

Standard fixtures and fittings also included a glove compartment with a lid, pockets in the doors and a well-equipped tool box. In the centre of the black, three-spoke steering wheel was the button for the two Bosch horns positioned behind the double-kidney grille. And in case the battery went flat, there was a hole for a starting crank in the radiator cover underneath the double-kidney grille – a standard feature at the time. The spare wheel was accommodated in a recess in the rear end.

Having made its debut as a racing car in 1936, series production of the BMW 328 finally began a year later. Far from being designed purely for racing, this was a “powerful everyday car for travel and sport”, as the advertising put it. In spring 1938 Bayerische Motoren Werke delivered the 200th BMW 328 to its owner and finally, only 464 examples were produced up to 1940, leaving the 328 as a sought-after rarity in classic car circles.