1939 BMW 327/328 Sports Cabriolet
The sports cabriolet combined sophisticated engineering with the shortened, boxed ladder chassis of the 326 saloon. Hydraulic brakes were fitted all around, while the Hurth four-speed manual gearbox featured a freewheel mechanism for clutchless low-speed changes.
Introduced in 1937, the 327 used a 1,971cc pushrod six producing 55 horsepower in standard form, though the 80-horsepower 328 engine could be specified at extra cost.
Rudolf Schleicher’s cylinder head design achieved hemispherical combustion chambers and inclined valves without an expensive overhead camshaft redesign.
Two rocker shafts (one above each row of valves) gave the engine an external appearance nearly indistinguishable from a twin-cam design, while the single block-mounted camshaft and pushrod actuation were retained. Downdraft intake ports contributed to the engine’s breathing.
Autocar magazine recorded 97 mph (156 km/h) during 1939 testing at Brooklands with the 328-powered variant. A total of 569 BMW 327 cabriolets were built through 1941, including those fitted with the 328 engine.
The engine’s adaptability later made it popular with British racing car constructors, notably Cooper and Frazer Nash, during the 1950s.
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