Mercedes-Benz M180 engine

The Mercedes Benz M180 Engine was a 2.2 litre (134ci) single overhead camshaft inline-6 cylinder engine introduced at the Frankfurt Motor show in April 1951 to power the company's new 220 (W187). It was the first engine with a cylinder bore greater than its stroke that Mercedes had installed in a production car

It spawned four variants through 1968, the final and largest being the 2.8 L M130. It was achieved by boring out and stroking the M180's original "over-square" 80mm bore × 72.8mm stroke 2.2 L to 86.5mm × 78.8mm, yielding a displacement of 2,778 cc/170ci.

Mercedes also unveiled at the 1951 Frankfurt Motor show a larger 3.0 litre M186 ‘big six’ inline-6 to power its new flagship 300 (W186) Adenauer four-door saloon.

While sharing many design features such as staggered valve arrangement and rockers running off a single overhead camshaft driven by a duplex cam-chain, the engines were of completely different design with little or no inter-changeability of parts.

The original M180 engine was rated at 80 hp (60 kW). It powered the W187 220 sedan, coupé, and cabriolet (Type A and B) from 1951 to 1955, the W180 220a sedan, coupé, and cabriolet from 1954 to 1956 and the W105 219 4-door sedan from 1956 to 1959.

It also powered the MB Unimog 404s, the military all-round vehicle: It was built from 1955 until 1980.

It was used as a "Pritsche", for towing light guns and carrying their crew, as ambulance, Radio vehicle, Fire vehicle, especially at airports and airbases.

Other Unimogs, agricultural used, used already OM-type engines (Öl Motor, or Diesel engine) but in the given period it should be more save, logistic reliable to use petrol engines for the military.

The W180 Ponton 220S Sedan, Coupe and Cabriolet of 1956-1959 benefited from the up-rated M180.924 which delivered 124 hp (92 kW). In 1958 Bosch mechanical fuel injection was added to the 2.2 litre six and the engine, now giving 113-134 hp, was redesignated M127. The M127 was fitted to the last of the Pontons: the rare 1958 W128 220SE, of which fewer than 4000 were produced.

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Wikipedia