M165

The organizers of the Gran Premio di Tripoli restricted their 1939 event to 1.5-liter voiturettes, a class in which Maserati and Alfa Romeo were established and Mercedes-Benz had nothing whatever. Albert Heeß answered with a 90° V8 of 1,492 cc, twin overhead camshafts per bank, four valves per cylinder and two horizontally mounted Roots blowers in series. The block was a welded steel structure, each bank fused to its water jacket and to the head; the crankshaft ran in roller bearings; magneto ignition let the car do without a battery and dynamo altogether.

Work began in September 1938, the first tests ran at Hockenheim in April 1939, and on 7 May Hermann Lang won at the Mellaha circuit at an average of 197.79 km/h, with Rudolf Caracciola second — a one-two over the Italian cars the new class had been meant to favor. It was the only race the engine ever ran. Fed a brew that was 86 per cent methyl alcohol, it drank 137 liters per 100 km. War came in September, and although the W 165 would have been eligible for Grand Prix racing until 1953, Mercedes-Benz never entered it again.