Mercedes-Benz M180 engine

The Mercedes-Benz M180 is a family of single overhead camshaft inline-six engines, with the related M127, M108, M129, M130, M114 and M123, used in Mercedes-Benz vehicles from the early 1950s to the mid 1980s. Designed by Wolf-Dieter Bensinger, the original 2.2 litre (2,196 cc) engine was introduced at the Frankfurt Motor Show in April 1951 to power the new 220 (W187). It has a reverse-flow cylinder head, staggered valves and rockers driven by a single overhead camshaft on a duplex chain, and was built in carburettor and fuel-injected forms with displacements from 2.2 to 2.8 litres. Although launched alongside the M186 big six, the two share almost no parts. The M180 shaped the four-cylinder M121 of 1955 and its diesel sibling the OM621 of 1958.