Mercedes-Benz M 103
| Mercedes Benz | |
|---|---|
| M 103 | |
| Manufacturer: | Mercedes Benz |
| Production period: | 1984-1995 |
| Design: | Six cylinder in - line engine |
| Displacement: | 2.6 liters (2599 cm³) 3.0 liters (2962 cm³) |
| Previous model: | M 110 , M 123 |
| Successor: | M 104 |
The M 103 is a six-cylinder in - line engine from Daimler-Benz with a displacement of 2.6 or 3.0 liters , cross-flow cylinder head and intake manifold injection . The gasoline engine was assignee of the M 123 (2.5 liters, a camshaft , counter-current cylinder head , carburetor ) and M 110 (2.8 liter, two camshafts, cross-flow cylinder head, carburetor or fuel injection).
The engine was presented by Mercedes-Benz at the end of 1984 together with the new W 124 car series . The successor M 104 with four-valve technology appeared in 1989, but the M 103 continued to be used, last until 1995 in the models with all-wheel drive ( 4MATIC ) of the W 124 series .
development
The M 103 engine was a fundamentally new design with similarities in design and production facilities to the OM 601/602/603 diesel engines introduced in 1983/84 and the M 102 four-cylinder petrol engine . It was more compact and lighter than its two predecessors. The 3-liter version, for example, was 42 kg lighter than the 2.8-liter M 110 despite the larger displacement with oil and water. Compared to the M 123 with carburettor and counter-flow cylinder head, the specific fuel consumption of the M 103 was 2.6 liters Displacement due to the cross-flow cylinder head and the intake manifold injection is lower. At the same time the maintenance is simplified since the setting of the valves by the same time in the M 102 introduced -Vierzylindern lash accounted and a finishing filter cartridge replaced the old loose paper oil filter. Compared to the M 110 with the complex DOHC valve control , the M 103 with a single camshaft (SOHC) was also considerably cheaper to produce.
The M 103 had an engine block made of gray cast iron and a cylinder head made of an aluminum alloy with two V-shaped valves per cylinder. These were actuated by a chain-driven camshaft located centrally above via rocker arms and hydraulic valve lifters. Both displacement variants had from the beginning the KE-Jetronic - manifold injection from Bosch and an electronic ignition , with a matching plug in the engine room to adjust the ignition timing to different octane fuels.
The displacement of the M 103 was initially lower than that of the M 110. In order to achieve roughly the same output, the displacement was increased from 2.8 to 3 liters. The 2.6-liter version was intended to close the gap between the large 2.3-liter four-cylinder and the 3-liter six-cylinder. However, it did not turn out to be a bestseller because the engine was nearly as expensive as the 3.0, with almost the same consumption and maintenance costs.
The reason for the change from DOHC - back to SOHC technology, was, in addition to the lower weight and lower production costs, the achievement of new ecological and economic goals, namely the introduction of regulated catalytic converter technology and, in view of the prevailing oil crisis, the necessary reduction in fuel consumption of the 6-cylinder -Motorization. The latter was part of a major modernization program at Daimler-Benz in the mid-1980s, which primarily affected the M 102, M 103 and M 117 engines and the newly designed diesel engines.
The smoothness of this unit is first class, especially the 2.6 liter version. The M 103 is one of the smoothest 6-cylinder engines ever built.
This engine was very interesting in the 190 E 2.6 model in the automatic version. With a well-behaved appearance (in contrast to the somewhat “rowdy” appearance of the sixteen-valve 190 E 2.3 16V with spoilers), the “little” Mercedes with this engine offered very impressive performance, with a comfortable drive design and still civil consumption.
With these engines, a number of tuning companies still known today, such as AMG , Brabus and Lorinser, grew up, even if some of them were already active. The usual measure was to bore out the engine and use a crankshaft with a longer stroke, so that 3.6 liters displacement and approx. 165 to 180 kW, with the later double-camshaft cylinder head then approx. 195 to 205 kW resulted. Occasionally, tuners even tried turbo-charged engine versions with well over 220 kW (300 hp).
The M 103 engines were among the most sophisticated engines in Daimler-Benz history, as the sales figures show. In the early years up to 1988 there were problems with the camshafts, some of which broke in. They were often exchanged later during service, sometimes without the customers even knowing about it. From 10/88 the M 103 was largely error-free in the revised version. The camshaft manufacturing technology, like the associated rocker arms, has been significantly revised in order to eliminate the main problem with the engine. But the injection system, ignition system, timing chain, etc. also experienced some detail improvements which made this engine one of the longest-lasting petrol engines in the Daimler-Benz car engine series.
The ADAC statistics from the late 1980s are no glory for this engine, this is due to frequent failures of the fuel pump control unit and defects in the ignition system.
In 1989 Daimler-Benz began to replace the M 103 with the M 104. The new engine with four-valve technology achieved an output of 162 kW (220 hp), which, however, (if the increased output was frequently used) was accompanied by higher fuel consumption and only slightly higher torque in the lower speed range. This in turn meant that the engine was not accepted in all press tests and so the M 103 remained in the range until the end of 1992. Only then did the second version of the M 104 come with a new ignition and injection system as well as camshaft adjustment, which largely replaced the M 103.
The M 103 with 3 liters displacement was built until 1995 in the W 124 4MATIC and in the SL R129 partly with an M 104 engine number (spare part no .: 103 011 10 01), because it was not worthwhile to use the complex all-wheel-drive technology that was available only sold in small numbers anyway, to adapt to the new M 104 engine. The M 103 thus remained in the passenger car range for 11 years (1984 to 1995) and, with several hundred thousand units, was one of the most successful engines in Daimler-Benz history.
Data, use
With the introduction of catalytic converter technology in 1985, the engines were available in RÜF (catalytic converter can be retrofitted) and KAT design. The performance was slightly lower compared to the standard version. Around 1988 the stroke was reduced slightly from 80.25 to 80.2 mm.
| execution | vehicle | Bore / stroke [mm] |
Cubic capacity [cm 3 ] |
Cat | compression | Power [kW] at speed [1 / min] |
Torque [Nm] at speed [1 / min] |
|---|---|---|---|---|---|---|---|
| 103.94x |
190 E 2.6 (W 201) 260 E (W 124) 260 SE (W 126) |
82.9 / 80.25 | 2599 | - | 10.0: 1 | 125 at 5800 | 230 at 4500 |
| RÜF | 9.2: 1 | 122 at 5800 | 228 at 4600 | ||||
| CAT | 9.2: 1 | 118 at 5800 | 220 at 4600 | ||||
| 103.98x |
300 E / CE / TE (124 series) 300 SE / SEL (126 series) 300 SL (R 107) |
88.5 / 80.25 | 2962 | - | 10.0: 1 | 140 at 5600 | 260 at 4250 |
| RÜF | 9.2: 1 | 138 at 5700 | 260 at 4400 | ||||
| CAT | 9.2: 1 | 132 at 5700 | 255 at 4400 | ||||
| 103.984 | 300 SL (R 129) | RÜF / CAT | 9.2: 1 | 140 at 5700 | 260 at 4500 | ||
| 103,987 | 300 GE (W463) | 88.5 / 80.25 | 2962 | CAT | 9.2: 1 | 125 at 5700 | 235 at 4500 |
