The OM647 engine is a 5-cylinder in-line diesel engine manufactured by Mercedes-Benz. Displacement 2.7 liters, 4 valves per cylinder, DOHC, common rail direct injection, turbocharging. Cast iron block and aluminum cylinder head. Model 647.961 was installed on Mercedes 211 W211 S211 and other models.
It was produced only in two versions – 647.961 (installed on 211.016 / 216) and 647.981. The cars bore the trade designation E270 CDI. The internal designation of the engine is OM 647 DE 27 LA. Displacement – 2685 cc, cylinder bore – 88.0 mm, piston stroke – 88.3 mm.
Specifications
| Displacement, cc | 2685 |
| Power, hp (kW) at rpm | 177 (130) / 4200 |
| Torque output, Nm (kg-m) at rpm | 400 (41) / 2600 425 (43) / 2000 425 (43) / 2600 |
| Fuel type | diesel fuel |
| Fuel consumption, L/100 km | 6.8 – 7.2 |
| Configuration | inline, five-cylinder |
| Cylinder head | DOHC |
| CO2 emission, g/km | 180 |
| Cylinder bore, mm | 88 |
| Valves per cylinder | 4 |
| Supercharger | Turbine |
| Compression ratio | 18 |
| Piston stroke, mm | 88.3 |
Features of OM 647
OM647 uses five cylinders. The engine is operated with a VGT or VNT turbocharger. The boost pressure is up to 1600 bar. There are 2 camshafts on the motor, the drive is carried out using a timing chain. There are 4 valves per cylinder, adjustable by pushers. There is an electronically controlled EGR valve. The control unit also controls the fuel pump, and the fuel is supplied metered.
Pre-injection, which means that a small portion of the fuel is burned before the main process. This makes it possible to heat the chamber, which contributes to a quick start and warm-up of the motor. Of course, the temperature regime and the pressure parameter are better maintained. Some modifications of these engines are equipped with a balance shaft rotating opposite the crankshaft at a higher speed.
Typical faults and modifications
- the fuel system fails frequently;
- crankshaft bearings rotate;
- particulate filters are deteriorating;
- Intake manifold flaps wear out prematurely.
OM647 has two modifications: 961 with 163 hp. at 4200 rpm and 981 with 156 hp. at 4200 rpm.
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