Mercedes-Benz M121 engine

Mercedes-Benz M121
Overview
Manufacturer	Mercedes-Benz
Production	1955-1967
Layout
Configuration	inline 4
Displacement	1.9 L (1,897 cc) 2.0 L (1,988 cc)
Cylinder bore	85 mm (3.35 in) 87 mm (3.43 in)
Piston stroke	83.6 mm (3.29 in)
Cylinder block material	Cast iron
Valvetrain	SOHC 2 valves x cyl.
Compression ratio	8.5:1, 9.0:1
Combustion
Fuel system	Twin parallel Solex 38PDSJ carburetors
Fuel type	Gasoline
Cooling system	Water cooled
Output
Power output	75–110 hp (56–82 kW; 76–112 PS)
Torque output	154 N⋅m (114 lb⋅ft)
Chronology
Predecessor	M136
Successor	M115

The Mercedes-Benz M121 engine was a 1.9 liter single overhead camshaft inline four-cylinder engine introduced by Mercedes in 1955 and used in various model lines during the 1950s and 1960s. Originally rated at 56 kW (76 PS; 75 hp) at 5500 rpm, it replaced the 1.8 liter M136 introduced in 1935, offering improved performance over the M136's side camshaft design.

Applications included mid-size sedans, such as the 190, the 190SL roadster, and trucks such as the Unimog and L319 models.