Mercedes-Benz M186 engine
| Mercedes-Benz M186 engine | |
|---|---|
| Overview | |
| Production | 1951–1967 |
| Layout | |
| Configuration | inline-6 |
| Displacement | 3.0 L; 182.8 cu in (2,996 cc) |
| Cylinder bore | 85 mm (3.35 in) |
| Piston stroke | 88 mm (3.46 in) |
| Cylinder head material | Aluminum |
| Valvetrain | SOHC 2 valves x cyl. |
| RPM range | |
| Max. engine speed | 6000 |
| Combustion | |
| Fuel system | 3 downdraft Solex carburetors Bosch Fuel injection |
| Fuel type | Gasoline |
| Cooling system | Water-cooled |
| Output | |
| Power output | 115–240 bhp (86–179 kW) |
| Torque output | 294 N⋅m (217 lb⋅ft) (M198 300 SL) |
The Mercedes Benz M186 Engine was a 3.0–litre single overhead camshaft inline-6 developed in the early 1950s to power the company's new flagship 300 "Adenauer" (W186) four-door saloon. It made its debut at the Frankfurt Motor Show in April 1951.
Designed to give reliable service under prolonged hard use, the iron block/aluminum head engine featured deep water jackets, an innovative diagonal head-to-block joint that allowed for oversized intake and exhaust valves, reverse-flow cylinder head, thermostatically controlled oil cooling, copper-lead bearings, and a hardened crankshaft.
Variants of the M186 went on to be used in the exclusive 300 S/300 Sc gran tourer, W194 300SL racer, iconic gullwing 300SL sports car and roadster, and Mercedes top-end 112-series 300SE sedans and limousines, and coupes and cabriolets of the early to mid-1960s. Production ended in 1967, four years after the introduction of the 600 Grosser Mercedes and the 6.3 L (386.4 cu in) M100 V-8.
The various versions of the engine (M186 – M199) produced from 115–240 bhp (86–179 kW) as compression ratios rose and the number of carburetors multiplied or were replaced with fuel-injection.
While sharing many design features with Mercedes' 2.2 L (134 cu in) M180 engine introduced at the same show (such as staggered valve arrangement and rockers running off a single overhead camshaft driven by a duplex cam-chain), the two were of completely different design with little or no inter-changeability of parts.
The term "big six" is sometimes used to distinguish the large block 3.0 L M186 from the small block M180 and its derivatives.