M186

Shown at Frankfurt in April 1951, the Mercedes-Benz 300 was the first German prestige saloon of the post-war era and, at 115 PS, among the quickest series cars the country could then build. Its six was less a new design than a reworked one: the pre-war M 159, a 2.6-liter unit with overhead valves, enlarged to three liters with the camshaft lifted into the head and driven by a duplex roller chain. Two Solex downdraft carburetors, 6.4:1 compression, and 155 km/h from a car weighing 1,770 kg.

Konrad Adenauer took delivery on 8 December 1951 and kept the type as his official car through three revisions, which is why Germans still say Adenauer-Mercedes rather than W 186. The 300 b of March 1954 raised compression to 7.4:1 for 125 PS and gained a brake servo — the 300 and the 300 SL were the first Mercedes-Benz cars to have one. Nothing German competed seriously: the BMW 502 was shorter and weaker, and the 505 built to answer the 300 never got past a single show car. Until the 600 of 1964, this engine and its injected successor powered the default German state car.