A series of diesel engines Mercedes OM615 has been produced since 1967 and, after numerous upgrades, is still on the assembly line in third world countries. This series has the following modifications: versions 2.0 l and 2.2 l – were installed on passenger cars Mercedes W115, W123, minibuses, as well as trucks 207D, 307D, 407D and their modifications.
The engine is located longitudinally – in the direction of travel. The engine cylinders are located in a block made of special cast iron. With a large wear of the cylinder walls, their boring is possible, after which repair pistons of the corresponding diameter must be installed.
At the bottom of the cylinder block is a crankshaft mounted on main bearings. The crankshaft is connected to the pistons by connecting rods and connecting rod bearings. The lower part of the block is closed by an oil sump, which contains oil for lubrication and engine cooling.
The cylinder head is attached to the top of the block. The intake and outlet manifolds are located on the right side of the head. The camshaft is centrally located at the top of the head and is driven by the crankshaft via a chain.
Specifications
| Engine’s type | diesel |
| Start of release | 1967 |
| Power, kW (hp) | 40 (55) 44 (60) |
| Displacement, cc | 1988 2197 |
| Number of cylinders | 4 |
| Number of valves | 8 |
| Torque output, Nm | 113 126 |
| Compression | 21:1 |
| Cylinder bore, mm | 87 |
| Piston stroke, mm | 92.4 |
| Crankshaft bearings | 5 |
| Configuration | inline |
| Fuel type | diesel fuel |
| Combustible mixture supply | direct injection |
| Turbine | suction pump |
| Cylinder head | SOHC/OHC |
| Timing mechanism | chain |
| Timing | rocker arm |
| Cooling | water |
The hydraulic tensioner ensures that the chain is always correctly tensioned. Timing valves are located vertically and are driven by the camshaft through special levers.
The engine is lubricated by an oil pump located at the front of the oil sump and driven by an intermediate shaft. The intermediate shaft is located on the left side and is driven by the crankshaft using the camshaft drive chain. Oil from the oil sump is supplied to the crankshaft bearings, camshaft bearings and cylinder mirrors through holes and lubrication channels.
Engine cooling is provided by a pump mounted at the front of the engine and driven by a V-belt, which simultaneously drives the generator.
Fuel is supplied by a high pressure fuel pump, which is chain driven from the crankshaft. Fuel is supplied to the injection pump by a mechanical fuel pump. A regulator located in the injection pump regulates the amount of fuel injected into the cylinders in accordance with the position of the accelerator pedal. At certain times, fuel is supplied to the vortex chamber of each of the cylinders using injectors.
Frequent problems of OM 615
Mercedes diesels were renowned for their incredible endurance. These powertrains are very reliable and can withstand huge mileage. However, there are also disadvantages:
- noisy operation and strong vibrations;
- leaking from the stuffing box at the rear end of the crankshaft;
- the timing chain has a resource of 200-250 thousand km;
- due to worn seals, the boost pump of the fuel pump is out of order.
Explanation of marking
| OM | Heavy Fuel Oil (Diesel) ICE |
| 615 | Engine type: in-line |
