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Mercedes-Benz M103 engine

Field	Value
name	Mercedes-Benz M103 engine
image	M103 R107.jpg
manufacturer	Mercedes-Benz
production	1984–1997
predecessor	M110 & M123
successor	M104
configuration	Naturally aspirated Inline-6
valvetrain	SOHC / 2 valves x cyl.
compression	9.2:1
redline	6200
displacement	2599 cc
2962 cc
power	118-140 kW
torque	220-260 Nm
bore	82.9 mm
88.5 mm
stroke	80.25 mm
fueltype	Gasoline
fuelsystem	Continuous Injection System - Electronic
coolingsystem	Water cooled
oilsystem	Wet sump

2962 cc 88.5 mm

The Mercedes-Benz M103 was a 15-degree, straight-6 crossflow cylinder headautomobile in production 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 "heart shaped" to a "HEMI" spherical combustion chamber.

Specifications

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	Layout	Combustion
Production period	1984–1997
Configuration	Straight-six
bore pitch	97 mm
Cylinder bore	82.9 mm	88.5 mm
Piston stroke	80.25 mm
Displacement	{{round	82.9^280.25pi*6/4000	0}} cc	{{round	88.5^280.25pi*6/4000	0}} cc
Max. engine speed	6,200/min
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
Lubrication	pressure circulation with Wet sump
Oil capacity	6 L
Cooling	water cooled engine cooling
Coolant capacity	8.5 L
Starter motor	1.5 kW electrical motor · since Jan 1988: 1.7 kW
Power w/ catalyst	last=TorqueCars	date=2020-09-17	title=All you need to know about tuning and performance parts on the M103 engine from Mercedes	url=https://www.torquecars.com/mercedes/m103-tuning.php	access-date=2025-11-02	website=TorqueCars}}	179 PS (176 HP)
@ engine speed	5,800/min	5,700/min
Torque w/ catalyst	220 Nm	255 Nm
@ engine speed	4,600/min	4,400/min
Power w/o catalyst	169 PS (166 HP)	190 PS (187 HP)
@ engine speed	5,800/min	5,700/min
Torque w/o catalyst	228 Nm	260 Nm
@ engine speed	5,800/min	4,400/min
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

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
Configuration	Straight-four	Straight-six
Cylinder bore	89 mm	95.5 mm	82.9 mm	88.5 mm

References

"M103.983 engine".
"260E M103 Engine Specs".
"M103 3.0L Engine - In-Depth Look at Design and Reliability".
(2025-02-28). "Mercedes-Benz M103 E26 2.6 engine - EngineDNA.com".
TorqueCars. (2020-09-17). "All you need to know about tuning and performance parts on the M103 engine from Mercedes".

Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

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