The Mercedes-Benz M103 is an inline six-cylinder engine with a displacement of 2.6 liters, produced from 1985 to 1993 at the factory in Stuttgart, Germany. This engine gained popularity due to its reliability, good performance and easy maintenance.
Main characteristics of the Mercedes-Benz M103 E26 engine
| Characteristics | Data |
|---|---|
| Production | Stuttgart-Bad Cannstatt Plant |
| Engine make | M103 |
| Years of manufacture | 1985-1993 |
| Cylinder block material | Cast iron |
| Power system | Injector |
| Engine type | Ready |
| Number of cylinders | 6 |
| Valves per cylinder | 2 |
| Cylinder diameter, mm | 82.9 |
| Piston stroke, mm | 80.2 |
| Compression ratio | 9.2 |
| Engine displacement, cc | 2599 |
| Engine power, hp/rpm | 160/5800 (166/5800) |
| Torque, Nm/rpm | 220/4600 (228/4600) |
| Environmental regulations | – |
| Motor weight, kg | ~170 |
| Oil consumption, gr./1000 km | To 1500 |
| Oil volume in the engine, l | 6.0 |
| At oil change, l | ~5.5 |
| Oil change interval, km | 7000-10000 |
| Operating temperature, °C | ~90 |
| Engine life, thousand km | Factory: – |
| Practical: 400+ | |
| Tuning, potential, hp | 600+ |
| Tuning without loss of resource | – |
Models
The M103 E26 engine was used in the following models:
- Mercedes-Benz 190 E (W201)
- Mercedes-Benz 260 E (W124)
- Mercedes-Benz 260 SE (W126)
Reliability and design of the Mercedes M103 2.6 engine
The younger variant of the 103 series developed and released as a replacement for the ancient M123 engine. The base for the 2.6-liter power unit was M103 E30, the cylinder diameter of which was reduced to 82.9 mm (the base engine is 88.5 mm). The cylinder head from M103 E30 is adapted for E26, the diameter of intake valves was reduced from 43 mm to 40 mm, exhaust valves from 39 mm to 35 mm. The fuel injection system is mechanical injection.
The timing drive uses a single-row chain subject to stretching. The fuel supply system is KE-Jetronic.
Since 1992, Mercedes began to produce a successor, the next version in the development of in-line six-cylinder engines, under the name of M 104 E28, which in 1993 completely took the place of its predecessor.
M 103 E 26 engine modifications
- M103.940 (1985 – 1992) – version for Mercedes-Benz 260 E W124, was available in a version without catalytic converter with an output of 166 hp at 5800 rpm, torque 228 Nm at 4600 rpm and with catalytic converter (CAT) with an output of 160 hp at 5800 rpm, torque 220 Nm at 4600 rpm.
- M103.941 (1985 – 1992) – analog of M 103.940 for Mercedes-Benz 260 SE/SEL W126.
- M103.942 (1986 – 1993) – analog of M 103.940 for Mercedes-Benz 190 E W201.
- M103.943 (1986 – 1992) – analog of M 103.940 for Mercedes-Benz 260 E 4Matic W124.
Mercedes M103 2.6 engine problems and disadvantages
- Most often, owners of cars with this power unit are faced with grease leaks.
- The weak places for leaks here are U-shaped gasket and crankshaft oil seal.
- The second most popular problem is engine malfunctions due to clogged injectors.
- The cause of oil spillage is usually in the oil caps and it goes away after replacing them.
- After 150,000 km the single-row timing chain may already stretch and require replacement.
Mercedes M103 engine tuning
Compressor
The situation with refining the M103 engine is similar to the four-cylinder M102: attempts to make a sporty atmospheric will cost a lot of money, and will not bring significant results, so you need to either inflate, or buy a Mercedes M104 engine, which has initially greater power, or a more modern Mercedes. This step will be the ideal choice in the price/quality ratio.
For supercharger enthusiasts, just install an Eaton M45 compressor from the M111.981 with intercooler (or better), ~300 cc injectors, Walbro 255 pump, tune to Megasquirt and drive until it falls apart. Further to collect on forged piston with compression ratio ~8 and blow in full.
An alternative option may be the purchase of a full turbo kit, such kits provide 400++ hp, the price of solutions is 1.5-2 times higher than the cost of the car itself.
MOTOR RATING: 4