Mercedes-Benz M103 engine
The M 103 is a straight six- cylinder petrol engine from Mercedes -Benz. It was introduced along with the car 124 series in 1984. This type of engine was the successor to the motor M 123 ( 250) and M 110 ( 280/280E ). In 1989, the successor M 104 M 103 The appeared was sold until 1995 in the models E 300 (T) 4MATIC 124 series.
Development
He was a fundamentally new design with similarities in design and manufacturing facilities for the 1983/84 imported diesel engines OM 601/602/603 and the four- cylinder petrol engine M 102, M 103 The engine was more compact and lighter than its predecessors. The 3-liter variant was compared with the M 110 lighter by 42 kg (including oil and water). The specific consumption and maintenance costs were also lower, since the setting of the valves accounted for by the same time introduced in M 102 automatic valve clearance compensation for maintenance and a finished filter cartridge replaced the old loose paper oil filter. The engine was also significantly cheaper to produce compared to the costly DOHC predecessor M 110
The M 103 had 2.6 liters or 3.0 liters, an engine block made of cast iron and a cross -flow cylinder head in light alloy with two V- shaped arrangement valves per cylinder. These were operated by a centrally located chain driven camshaft via cam followers with hydraulic valve clearance compensation. Both variants had from the beginning, the Bosch KE- Jetronic fuel injection and electronic ignition, with a matching plug in the engine room to adjust the ignition timing to different fuel quality.
The specific power output of the M 103 was initially lower than that of its predecessor M 110 To obtain a same total power, we therefore raised the standard engine on the engine capacity of 2.8 to 3.0 liters. The 2.6 liter version should close the gap between the large 2.3-liter 4- cylinder and 3.0-liter 6- cylinder. It proved, however, not a bestseller because the engine nearly as expensive as the 3.0 was, at almost the same usage and same maintenance costs.
The reason for the change of DOHC back to SOHC technology was next to the lower weight and lower production costs reaching new ecological and economic objectives, namely, the introduction of regulated catalytic converter technology and, given current oil crisis, the need to reduce fuel consumption of the 6- cylinder motorization. The latter was in his mid -80s part of a major modernization program at Daimler -Benz, which impact primarily on the motors M 102, M 103 and M 117 and the newly designed diesel engines.
Is excellent for the smooth running of this aggregate, especially the 2.6 -liter version. The M 103 is one of the smoothest six -cylinder engines that were ever built.
Very interesting, this engine was the model 190 E 2.6 in the automatic version. In gesittetem exterior (as opposed to something " krawalligen " appearance of Sechzehnventilers 190 E 2.3 16V with spoilers ) of the "small" Mercedes offered with this engine very impressive performance, at the same time comfortable drive design and even civilian consumption.
With these engines, some still known tuning companies such as AMG, Brabus and Lorinser were great when they were partly also previously worked. Common measure was the boring of the engine and the use of a crankshaft with longer stroke, so that displacement of 3.6 liters and about 165 to 180 kW, with the later twin cam cylinder head then resulted in approximately 195-205 kW. Encircled tuner even tried to turbo- charged engine versions with well over 220 kW ( 300 hp).
The M 103 engines were among the most advanced engines of Daimler -Benz history, as evidenced by the sales figures. In the early years to 1988 there were problems with the camshaft, this ran partially. Often they were replaced later in the service, in part, without the customer learned about it at all. 10 /88 M 103 was then largely error-free in the revised version. The camshaft production technology has been revised as are the associated cam follower clear so as to eliminate the main problem of the engine. However, injection system, ignition system, timing chain, etc. underwent some improvements which made this engine to one of the most durable gasoline engines Daimler- Benz passenger car engine series.
The ADAC statistics from the late 1980s are no credit for this engine, this is due to frequent failures of the fuel pump control device as well as to defects in the ignition system.
After the end of the 80s, the oil crisis was largely forgotten, Daimler -Benz tried to replace the M 103, 1990 by the M 104. The first version of the engine M 104 had a 4-valve cylinder head, the other basic design remained the same. So the new engine achieved an output of 162 kW ( 220 hp ), but at the expense of torque in the lower speed range at higher fuel consumption. This in turn meant that the engine in all press testing was not accepted and so the M 103 remained in the program until the end of 1992. Only then came the second version of the M 104 with a new ignition and fuel injection and camshaft adjustment, which largely then sends M 103 retired.
The M 103 was, however, continued to be built until 1995 in the W 124 4-Matic, because it was not worth the expensive wheel-drive technology, which already sold only in smaller numbers, adapted to the new M 104. This left the M 103 from 1984 to 1995 for 11 years in the passenger car program and counted with several hundred thousand units of the most successful engines of Daimler -Benz history.
Data, using
With the introduction of catalyst technology in 1985 there were the engines in RÜF (catalyst retrofit) and KAT- execution. The performances were compared to the standard version, somewhat lower. Approximately in 1988 the stroke was reduced slightly from 80.25 to 80.2 mm.
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