Mercedes-Benz M121 engine

Mercedes-Benz M121
Overview
ManufacturerMercedes-Benz
Production1955-1967
Layout
Configurationinline 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 stroke83.6 mm (3.29 in)
Cylinder block materialCast iron
ValvetrainSOHC 2 valves x cyl.
Compression ratio8.5:1, 9.0:1
Combustion
Fuel systemTwin parallel Solex 38PDSJ carburetors
Fuel typeGasoline
Cooling systemWater cooled
Output
Power output75–110 hp (56–82 kW; 76–112 PS)
Torque output154 N⋅m (114 lb⋅ft)
Chronology
PredecessorM136
SuccessorM115

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.