M180

Credited to Wolf-Dieter Bensinger, it appeared in the 220 of April 1951: the company’s first post-war six and its first short-stroke petrol engine, 2,195 cc from 80 × 72.8 mm, with a chain-driven overhead camshaft, a counterflow head and a four-bearing crankshaft. It went into a barely altered 170 S chassis wearing pre-war bodywork, and it was the reason the press forgave the styling — 140 km/h in a class that had been making do with 52 PS. From 1954 the cast-iron cylinder head gave way to light alloy.

What followed was a dynasty. The same block and cam-in-head layout underpinned the M 127, the M 108 and M 129, and the M 130, and through the M 130 the twin-cam M 110 as well; the last of the line was built in 1989, in a 280 GE. One of the odder branches was military. NATO standardization required petrol engines in Unimogs so that tanks, jeeps and trucks could draw on a single fuel supply and start in deep cold, and 2.2-liter M 180s were still being made for the Unimog 404 into the late 1970s.