KNOWPIA
WELCOME TO KNOWPIA
Mercedes-Benz OM621 engine 
Summary
The OM621 is an inline-four diesel engine produced by Mercedes-Benz, from 1956 to 1968. It was succeeded by the OM615 engine.
| Mercedes-Benz OM621 | |
|---|---|
| Overview | |
| Manufacturer | Mercedes-Benz |
| Production | 1956–1968 |
| Layout | |
| Configuration | Inline-four engine |
| Displacement |
|
| Cylinder bore | 85–87 mm (3.35–3.43 in) |
| Piston stroke | 83.6 mm (3.29 in) |
| Cylinder block material | Cast Iron |
| Cylinder head material | Cast Iron |
| Valvetrain | SOHC |
| Compression ratio | 18.0:1 |
| Combustion | |
| Fuel system | Indirect injection |
| Fuel type | Diesel |
| Cooling system | Water cooled |
| Output | |
| Power output | 35–40 kW (47–54 hp) |
| Torque output | 108–118 N⋅m (80–87 lb⋅ft) |
| Chronology | |
| Predecessor | Mercedes-Benz OM636 engine |
| Successor | Mercedes-Benz OM615 engine |
Design edit
The OM621 is based on the petrol M121 engine, but features revised camshafts, cylinder head, pistons, and fuel injection system.[1] In 1961, the engine capacity was increased to 2.0 L (1,988 cc) and power was uprated to 55 PS (40 kW) for use in the newly introduced W110 models. After being replaced by the OM615, a 2.2 L (2,197 cc) updated version of the OM621 engine was used solely in Unimog vehicles until 1988.[2]
Models edit
| Engine | Displacement | Power | Torque | Years |
|---|---|---|---|---|
| OM621 I | 1.9 L (1,897 cc) | 37 kW (50 PS) at 4,000 rpm |
108 N⋅m (80 lb⋅ft) at 2,200 rpm |
1958–1959 |
| OM621 IV | 2.0 L (1,988 cc) | 35 kW (48 PS) at 3,800 rpm |
1961–1962 | |
| OM621 III / VIII | 40 kW (55 PS) at 4,200 rpm |
118 N⋅m (87 lb⋅ft) at 2,400 rpm |
1961–1968 | |
| 2.2 L (2,197 cc) | 40 kW (55 PS) at 3,000 rpm |
1966–1988 |
OM621 (37 kW version) edit
- 1958–1959 W121 190D, 190Db
OM621 (35 kW version) edit
- 1961–1962 W120 180Dc
OM621 (40 kW version) edit
- 1961–1965 W110 190Dc
- 1965–1968 W110 200D
- 1966–1988 Unimog 421