Mercedes-Benz M180 engine

Mercedes-Benz M180
M130 engine of a 1971 280SL
Overview
Manufacturer	Daimler-Benz
Designer	Wolf-Dieter Bensinger[1]
Production	1951-1985
Layout
Configuration	Inline-6
Displacement	2.2 L; 134.0 cu in (2,196 cc) 2.3 L; 140.8 cu in (2,307 cc) 2.5 L; 152.3 cu in (2,496 cc) 2.8 L; 169.5 cu in (2,778 cc)
Cylinder bore	80 mm (3.15 in) 82 mm (3.23 in) 86.5 mm (3.41 in)
Piston stroke	72.8 mm (2.87 in) 78.8 mm (3.10 in)
Valvetrain	SOHC 2 valves x cyl.
Combustion
Fuel system	Solex carburetor Mechanical fuel injection
Management	Bosch D-Jetronic
Fuel type	Gasoline
Cooling system	Water cooled
Output
Power output	80–134 bhp (60–100 kW; 81–136 PS)
Chronology
Predecessor	Mercedes-Benz M153 engine (pre-war) Mercedes-Benz M189 engine (of M130)
Successor	Mercedes-Benz M110 engine (of M130) Mercedes-Benz M103 engine (of M123)

The Mercedes Benz M180 engine was a 2.2 L; 134.0 cu in (2,196 cc) 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, while using a reverse-flow cylinder head .

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" bore × stroke of 80 mm × 72.8 mm (3.15 in × 2.87 in) 2.2 L; 134.0 cu in (2,196 cc) to 86.5 mm × 78.8 mm (3.41 in × 3.10 in), yielding a displacement of 2.8 L; 169.5 cu in (2,778 cc).

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.^[2]