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Mercedes-Benz M103 engine

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Mercedes-Benz M103 engine
Overview
ManufacturerMercedes-Benz
Production1984–1997
Layout
ConfigurationNaturally aspirated Straight-6
Displacement158.6 cu in (2,599 cc)
180.8 cu in (2,962 cc)
Cylinder bore82.9 mm (3.264 in)
88.5 mm (3.484 in)
Piston stroke80.25 mm (3.159 in)
ValvetrainSOHC / 2 valves x cyl.
Compression ratio9.2:1
RPM range
Max. engine speed6200
Combustion
Fuel systemContinuous Injection System - Electronic
Fuel typeGasoline
Oil systemWet sump
Cooling systemWater cooled
Output
Power output118–140 kW (160–190 PS; 158–188 hp)
Torque output220–260 N⋅m (162–192 lb⋅ft)
Chronology
PredecessorM110 & M123
SuccessorM104
An egg being cooked on a 3.0 L M103 engine

The Mercedes-Benz M103 is a straight-6 15 degrees, crossflow cylinder head with an inclination to the right, automobile engine produced from 1984 to 1997. It is a single overhead cam design with 2 valves per cylinder. The M103 was replaced by the M104 starting in 1989. This engine received several updates over the years of production, one of the updates was a change from a spherical combustion chamber to a "heart shaped" combustion chamber.

Specifications

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The only mechanical differences from the M103 3.0 L to the M103 2.6 L were the smaller bore and intake valves, with a slightly different airbox. The CIS-E components between 2.6 and 3.0 variants are all shared for any given model year with the exception of the ECU making engine swaps from 2.6 to 3.0 virtually bolt-in.

Model 260 300
Type 103.940 103.980
Production period 1984–1997
Layout
Configuration Straight-six
bore pitch 97 mm (3.819 in)
Cylinder bore 82.9 mm (3.264 in) 88.5 mm (3.484 in)
Piston stroke 80.25 mm (3.159 in)
Displacement 2,599 cc (158.6 cu in) 2,962 cc (180.8 cu in)
Max. engine speed 6,200/min
Combustion
Principle Internal combustion engine
Mode of operation Four-stroke
Fuel type gasoline
Fuel octane 95 RON/85 MON · 91 RON/81MON via plug-in
jumper located in the engine compartment
Fuel system CIS-E (Continuous Injection System)
Ignition system electronic engine control unit
Firing order 1–5–3–6–2–4
Valvetrain SOHC
Valves per cylinder 2
Configuration V-shaped overhead crossflow
Camshaft drive simple roller-type chain
Aspiration Naturally aspirated
Compression ratio 9.2 : 1
Management
Lubrication pressure circulation with Wet sump
Oil capacity 6 L (1.6 US gal; 1.3 imp gal)
Cooling water cooled engine cooling
Coolant capacity 8.5 litres (2.2 US gal; 1.9 imp gal)
Starter motor 1.5 kW electrical motor · since Jan 1988: 1.7 kW
Performance
Power w/ catalyst 160 PS (118 kW; 158 hp) 180 PS (132 kW; 178 hp)
@ engine speed 5,800/min 5,700/min
Torque w/ catalyst 220 N⋅m (162 lb⋅ft) 255 N⋅m (188 lb⋅ft)
@ engine speed 4,600/min 4,400/min
Power w/o catalyst 170 PS (125 kW; 168 hp) 190 PS (140 kW; 187 hp)
@ engine speed 5,800/min 5,700/min
Torque w/o catalyst 228 N⋅m (168 lb⋅ft) 260 N⋅m (192 lb⋅ft)
@ engine speed 4,600/min 4,400/min
Applications
W201 190 E 2.6
W124 260 E · 300 E 2.6 300 E
W126 260 SE 300 SE · 300 SEL
R107 SL 300 SL
R129 SL 300 SL
W463 300 GE
Isdera Spyder 036i Isdera Spyder 036i

Data accuracy

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The M 102 and M 103 engine family has a common piston stroke of 80.25 mm. As only one decimal place is usually given, a large number of publications are in circulation with the incomplete specification of 80.2 mm. This applies in particular to more recent publications after production was discontinued. As a result, the inaccurate figures of 2.597 cc instead of the actual 2.599 cc for the 2.6 l engine and 2.960 cc instead of 2.962 cc for the 3.0 l engine have become established.

Model 200 230 260 300
Engine M 102 M 103
Type 102.92X–96X 102.98X 103.940 103.980
Configuration Straight-four Straight-six
Cylinder bore 89 mm (3.504 in) 95.5 mm (3.760 in) 82.9 mm (3.264 in) 88.5 mm (3.484 in)
Complete Piston stroke 80.25 mm (3.159 in)
Accurate Displacement 1,997 cc (121.9 cu in)
1,996.99 cc (121.864 cu in)
2,299 cc (140.3 cu in)
2,299.33 cc (140.314 cu in)
2,599 cc (158.6 cu in)
2,598.93 cc (158.596 cu in)
2,962 cc (180.8 cu in)
2,961.92 cc (180.747 cu in)
Incomplete Piston stroke 80.2 mm (3.157 in)
Inaccurate Displacement 1,996 cc (121.8 cu in)
1,995.74 cc (121.788 cu in)
2,298 cc (140.2 cu in)
2,297.90 cc (140.226 cu in)
2,597 cc (158.5 cu in)
2,597.31 cc (158.498 cu in)
2,960 cc (180.6 cu in)
2,960.07 cc (180.635 cu in)