The Mercedes-Benz M120 was a V12 petrol engine that was introduced in 1991. During its production, the M120 engine was used in the W140 600 SE and 600 SEL, W140 S600, C140 600 SEC, C140 CL 600, R129 600 SL and R129 SL 600. The M120 engine was replaced by the M137 engine in 1998.
Manufactured in Stuttgart, Germany, the M120 engine had a 60-degree ‘V’ cylinder configuration, an aluminium block with Alusil (silicon/aluminium) cylinder liners, an aluminium cylinder head, forged steel connecting rods, double overhead camshafts per cylinder bank (duplex chain-driven), a variable intake camshaft, four valves per cylinder and a compression ratio of 10.0:1.
The 120.980 and 120.981 engines had electronic Bosch LH-Jetronic (LH 4.1) ignition with two hot-wire air mass sensors and two distributors. From September 1995, the 120.983 engine which had fully electronic (i.e. distributorless) Bosch Motronic (ME 1.0) ignition with a coil for each plug.
| Engine | Bore/Stroke | Capacity | Peak power | Peak torque | Production |
|---|---|---|---|---|---|
| M120 E 60 | 89.0 x 80.2 | 5987 cc | 300 kW at 5200 rpm | 580 Nm at 3800 rpm | 1991 to 09/1992 |
| 290 kW at 5200 rpm | 570 Nm at 3800 rpm | 09/1992 to 1998 |
