Mercedes-Benz M121 engine
| Mercedes-Benz M121 | |
|---|---|
| Overview | |
| Manufacturer | Mercedes-Benz |
| Production | 1955-1967 |
| Layout | |
| Configuration | inline 4 |
| Displacement |
|
| Cylinder bore |
|
| 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 single overhead camshaft inline four-cylinder engine used by Mercedes-Benz in 1955 in various model lines during the 1950s and 1960s. Based on the M180 six cylinder engine, introduced three years prior, it replaced the OHV M136 motor, that was in production since 1935.
The engine's first application was in the W121 Mercedes 190SL luxury roadster in May of 1955, built until Februarly 1962. After 1956 and until the close of 1967 it would power the entry level 180, 190 and 200 series of the W120, W121 and W110 sedans.
It 1958 a diesel version, OM621 would be produced alongside, sharing many of the components. In 1968 the engine would modernised into the M115, which would power the W115 and later the W123 sedans, and the W460 G-wagen, until it's retirement in 1985. The diesel counterpart, the OM615 would also be produced until 1985. In 1973 a larger displacement 2.3 litre OM616 will join the lineup, and in 1974 a five cylinder OM617 will follow.
In addition and trucks such as the Unimog and L319 models. The M121 series was in production until 1967, when the M115 engine took its place.