Mercedes-Benz Engine

M103

The Mercedes-Benz M103 is a SOHC I6 gasoline piston engine.

Years
1984–1995
Configuration
I6
Fuel
Gasoline
Top power
190 PS

The six that carried Mercedes-Benz through the switch to unleaded petrol.

Introduced in 1984, the M103 replaced the twin-cam M110 and the M123 with something deliberately simpler: one overhead camshaft on a roller chain, two valves per cylinder in a 15° crossflow head, CIS-E injection, a wet sump. Two sizes shared a single 80.25 mm stroke — 2.6 liters on an 82.9 mm bore, 3.0 on 88.5 mm — and the mechanical differences between them came down to bore, intake valves and airbox, which is why one drops into the other almost unaltered.

A catalytic converter cost the three-liter eleven PS, 190 falling to 179, and cars of the period carried a jumper plug in the engine bay so the ignition could be set for 95 or 91 RON depending on what the local pumps sold. The spread of applications was enormous: 190 E 2.6, 260 E and 300 E, 260 SE and 300 SE, the R 107 and R 129 300 SL, the 300 GE. The 24-valve M104 arrived above it in 1989, but the single-cam six stayed in production alongside for years.

Versions.

Every factory version of the M103.

VersionDisplacementBore × StrokeCompressionPowerTorque
103.940 (M 103 E 26 — ECE)2,599 cc 82.9 × 80.25 mm 10.0125 kW (168 hp; 170 PS) at 5,800 rpm230 N·m (170 lb·ft) at 4,500 rpm
103.940 (M 103 E 26 — RÜF)2,599 cc 82.9 × 80.25 mm 9.2122 kW (164 hp; 166 PS) at 5,800 rpm228 N·m (168 lb·ft) at 4,600 rpm
103.940 (M 103 E 26 — catalyst)2,599 cc 82.9 × 80.25 mm 9.2118 kW (158 hp; 160 PS) at 5,800 rpm220 N·m (162 lb·ft) at 4,600 rpm
103.941 (M 103 E 26 — without catalyst)2,599 cc 82.9 × 80.25 mm 9.2122 kW (164 hp; 166 PS) at 5,800 rpm228 N·m (168 lb·ft) at 4,600 rpm
103.941 (M 103 E 26 — catalyst)2,599 cc 82.9 × 80.25 mm 9.2118 kW (158 hp; 160 PS) at 5,800 rpm220 N·m (162 lb·ft) at 4,600 rpm
103.942 (M 103 E 26 — catalyst)2,597 cc 82.9 × 80.2 mm 9.2118 kW (158 hp; 160 PS) at 5,800 rpm220 N·m (162 lb·ft) at 4,600 rpm
103.942 (M 103 E 26 — RÜF)2,597 cc 82.9 × 80.2 mm 9.2122 kW (164 hp; 166 PS) at 5,800 rpm228 N·m (168 lb·ft) at 4,600 rpm
103.943 (M 103 E 26 — catalyst)2,599 cc 82.9 × 80.25 mm 9.2118 kW (158 hp; 160 PS) at 5,800 rpm220 N·m (162 lb·ft) at 4,600 rpm
103.943 (M 103 E 26 — RÜF)2,599 cc 82.9 × 80.25 mm 9.2122 kW (164 hp; 166 PS) at 5,800 rpm228 N·m (168 lb·ft) at 4,600 rpm
103.9802,962 cc 88.5 × 80.25 mm 10.0140 kW (187 hp; 190 PS) at 5,600 rpm260 N·m (192 lb·ft) at 4,250 rpm
103.981 (M 103 E 30 — without catalyst)2,962 cc 88.5 × 80.25 mm 9.2138 kW (185 hp; 188 PS) at 5,700 rpm260 N·m (192 lb·ft) at 4,400 rpm
103.981 (M 103 E 30 — catalyst)2,962 cc 88.5 × 80.25 mm 9.2132 kW (177 hp; 179 PS) at 5,700 rpm255 N·m (188 lb·ft) at 4,400 rpm
103.982 (M 103 E 30 — without catalyst)2,962 cc 88.5 × 80.25 mm 9.2138 kW (185 hp; 188 PS) at 5,700 rpm255 N·m (188 lb·ft) at 4,400 rpm
103.982 (M 103 E 30 — catalyst)2,962 cc 88.5 × 80.25 mm 9.2132 kW (178 hp; 180 PS) at 5,700 rpm250 N·m (184 lb·ft) at 4,400 rpm
103.983 (M 103 E 30 — without catalyst)2,962 cc 88.5 × 80.25 mm 9.2138 kW (185 hp; 188 PS) at 5,700 rpm260 N·m (192 lb·ft) at 4,400 rpm
103.983 (M 103 E 30 — catalyst)2,960 cc 88.5 × 80.2 mm 9.2132 kW (178 hp; 180 PS) at 5,700 rpm255 N·m (188 lb·ft) at 4,400 rpm
103.9842,960 cc 88.5 × 80.2 mm 9.2140 kW (188 hp; 190 PS) at 5,700 rpm260 N·m (192 lb·ft) at 4,500 rpm
103.985 (M 103 E 30 — catalyst)2,962 cc 88.5 × 80.25 mm 9.2132 kW (178 hp; 180 PS) at 5,700 rpm255 N·m (188 lb·ft) at 4,400 rpm
103.985 (M 103 E 30 — RÜF)2,962 cc 88.5 × 80.25 mm 9.2138 kW (185 hp; 188 PS) at 5,700 rpm260 N·m (192 lb·ft) at 4,400 rpm
103.9872,980 cc 88.5 × 80.2 mm 9.2125 kW (168 hp; 170 PS) at 5,500 rpm235 N·m (173 lb·ft) at 4,500 rpm

Applications.

Every model powered by the M103.

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