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Mercedes-Benz M103 engine

{{No sources|date=June 2019}}{{Globalize|date=December 2010}}

{{Infobox automobile engine

| 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 = {{convert|2599|cc|cuin|1|abbr=on|disp=flip}}
{{convert|2962|cc|cuin|1|abbr=on|disp=flip}}

| power = {{convert|118-140|kW|PS hp|0|abbr=on}}

| torque = {{convert|220-260|Nm|lbft|0|abbr=on}}

| bore = {{convert|82.9|mm|in|3|abbr=on}}
{{convert|88.5|mm|in|3|abbr=on}}

| stroke = {{convert|80.25|mm|in|3|abbr=on}}

| fueltype = Gasoline

| fuelsystem = Continuous Injection System - Electronic

| coolingsystem = Water cooled

| oilsystem = Wet sump

}}

File:M103 egg.jpg 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 "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.

class=wikitable style="text-align:center"

! Model

! 260

! 300

Type

! 103.940

! 103.980

Production period

| colspan=2 | 1984–1997

colspan=3 | Layout
Configuration

| colspan=2 | Straight-six

bore pitch

| colspan=2 | {{convert|97|mm|in|3|abbr=on}}

Cylinder bore

| {{convert|82.9|mm|in|3|abbr=on}}

| {{convert|88.5|mm|in|3|abbr=on}}

Piston stroke

| colspan=2 | {{convert|80.25|mm|in|3|abbr=on}}

Displacement

| {{convert|{{round|82.9^2*80.25*pi*6/4000|0}}|cc|cuin|1|abbr=on

}

| {{convert|{{round|88.5^2*80.25*pi*6/4000|0}}|cc|cuin|1|abbr=on|}}

|-

| Max. engine speed

| colspan=2 | 6,200/min

|-

! colspan=3 | Combustion

|-

| Principle

| colspan=2 | Internal combustion engine

|-

| Mode of operation

| colspan=2 | Four-stroke

|-

| Fuel type

| colspan=2 | gasoline

|-

| Fuel octane

| colspan=2 | 95 RON/85 MON · 91 RON/81MON via plug-in
jumper located in the engine compartment

|-

| Fuel system

| colspan=2 | CIS-E (Continuous Injection System)

|-

| Ignition system

| colspan=2 | electronic engine control unit

|-

| Firing order

| colspan=2 | 1–5–3–6–2–4

|-

| Valvetrain

| colspan=2 | SOHC

|-

| Valves per cylinder

| colspan=2 | 2

|-

| Configuration

| colspan=2 | V-shaped overhead crossflow

|-

| Camshaft drive

| colspan=2 | simple roller-type chain

|-

| Aspiration

| colspan=2 | Naturally aspirated

|-

| Compression ratio

| colspan=2 | 9.2 : 1

|-

! colspan=3 | Management

|-

| Lubrication

| colspan=2 | pressure circulation with Wet sump

|-

| Oil capacity

| colspan=2 | {{convert|6|L|USgal impgal|abbr=on}}

|-

| Cooling

| colspan=2 | water cooled engine cooling

|-

| Coolant capacity

| colspan=2 | {{convert|8.5|L|USgal impgal}}

|-

| Starter motor

| colspan=2 | 1.5 kW electrical motor · since Jan 1988: 1.7 kW

|-

! colspan=3 | Performance

|-

| Power w/ catalyst

| {{convert|160|PS|kW hp|0|abbr=on}}

| {{convert|180|PS|kW hp|0|abbr=on}}

|-

| @ engine speed

| 5,800/min

| 5,700/min

|-

| Torque w/ catalyst

| {{convert|220|Nm|lbft|0|abbr=on}}

| {{convert|255|Nm|lbft|0|abbr=on}}

|-

| @ engine speed

| 4,600/min

| 4,400/min

|-

| Power w/o catalyst

| {{convert|170|PS|kW hp|0|abbr=on}}

| {{convert|190|PS|kW hp|0|abbr=on}}

|-

| @ engine speed

| 5,800/min

| 5,700/min

|-

| Torque w/o catalyst

| {{convert|228|Nm|lbft|0|abbr=on}}

| {{convert|260|Nm|lbft|0|abbr=on}}

|-

| @ engine speed

| 4,600/min

| 4,400/min

|-

! colspan=3 | 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

|}

{{notelist|group=efn}}

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.

class=wikitable style="text-align:center"

! Model

! 200

! 230

! 260

! 300

Engine

! colspan=2 | M 102

! colspan=2 | M 103

Type

! 102.92X–96X

! 102.98X

! 103.940

! 103.980

Configuration

| colspan=2 | Straight-four

| colspan=2 | Straight-six

Cylinder bore

| {{convert|89|mm|in|3|abbr=on}}

| {{convert|95.5|mm|in|3|abbr=on}}

| {{convert|82.9|mm|in|3|abbr=on}}

| {{convert|88.5|mm|in|3|abbr=on}}

{{font color|green|Complete Piston stroke}}

| colspan=4 |{{font color|green|{{convert|80.25|mm|in|3|abbr=on}}}}

{{font color|green|Accurate Displacement}}

| {{font color|green|{{convert|{{round|89^2*80.25*pi*4/4000|0}}|cc|cuin|1|abbr=on

}}}
{{font color|green|{{convert|{{round|89^2*80.25*pi*4/4000|2}}|cc|cuin|3|abbr=on|}}}}

| {{font color|green|{{convert|{{round|95.5^2*80.25*pi*4/4000|0}}|cc|cuin|1|abbr=on|}}}}
{{font color|green|{{convert|{{round|95.5^2*80.25*pi*4/4000|2}}|cc|cuin|3|abbr=on|}}}}

| {{font color|green|{{convert|{{round|82.9^2*80.25*pi*6/4000|0}}|cc|cuin|1|abbr=on|}}}}
{{font color|green|{{convert|{{round|82.9^2*80.25*pi*6/4000|2}}|cc|cuin|3|abbr=on|}}}}

| {{font color|green|{{convert|{{round|88.5^2*80.25*pi*6/4000|0}}|cc|cuin|1|abbr=on|}}}}
{{font color|green|{{convert|{{round|88.5^2*80.25*pi*6/4000|2}}|cc|cuin|3|abbr=on|}}}}

|-

| {{font color|red|Incomplete Piston stroke}}

| colspan=4 |{{font color|red|{{convert|80.2|mm|in|3|abbr=on}}}}

|-

| {{font color|red|Inaccurate Displacement}}

| {{font color|red|{{convert|{{round|89^2*80.2*pi*4/4000|0}}|cc|cuin|1|abbr=on|}}}}
{{font color|red|{{convert|{{round|89^2*80.2*pi*4/4000|2}}|cc|cuin|3|abbr=on|}}}}

| {{font color|red|{{convert|{{round|95.5^2*80.2*pi*4/4000|0}}|cc|cuin|1|abbr=on|}}}}
{{font color|red|{{convert|{{round|95.5^2*80.2*pi*4/4000|2}}|cc|cuin|3|abbr=on|}}}}

| {{font color|red|{{convert|{{round|82.9^2*80.2*pi*6/4000|0}}|cc|cuin|1|abbr=on|}}}}
{{font color|red|{{convert|{{round|82.9^2*80.2*pi*6/4000|2}}|cc|cuin|3|abbr=on|}}}}

| {{font color|red|{{convert|{{round|88.5^2*80.2*pi*6/4000|0}}|cc|cuin|1|abbr=on|}}}}
{{font color|red|{{convert|{{round|88.5^2*80.2*pi*6/4000|2}}|cc|cuin|3|abbr=on|}}}}

|}

{{DEFAULTSORT:Mercedes-Benz M103 Engine}}

M103

Category:Straight-six engines