| Mercedes-Benz M 120 engine | |
|---|---|
| Overview | |
| Manufacturer | Mercedes-Benz |
| Layout | |
| Configuration | Naturally aspirated 60° V12 |
| Displacement | |
| Cylinder bore | 89 mm (3.504 in) 91 mm (3.583 in) 91.5 mm (3.602 in) |
| Piston stroke | 80.2 mm (3.157 in) 90.4 mm (3.559 in) 92.4 mm (3.638 in) |
| Cylinder block material | Aluminium, Alusil bores |
| Cylinder head material | Aluminium |
| Valvetrain | DOHC 4 valves x cyl. |
| Combustion | |
| Fuel system | Sequential fuel injection |
| Fuel type | Gasoline |
| Cooling system | Water cooled |
| Output | |
| Power output | 394–850 PS (290–625 kW; 389–838 hp) |
| Chronology | |
| Predecessor | M 154 |
| Successor | M 137 |
The Mercedes-Benz M 120 engine is a naturally aspirated high-performance automobile piston V12 engine family used in the 1990s and 2000s in Mercedes-Benz' flagship models. The engine was a response to BMW's M70 V12 engine, introduced in 1987. While the 5-litre BMW unit developed 300 metric horsepower (221 kW), Mercedes-Benz upped the ante considerably by creating a 6-litre, 300-kilowatt (408 PS) engine.
The M 120 family was built in Stuttgart, Germany. It has an aluminium engine block lined with silicon/aluminium. The aluminium DOHC cylinder heads are 4 valves per cylinder designs. It uses sequential fuel injection (SFI) and features forged steel connecting rods.
The M 120 was eventually replaced by the smaller (5.8 litres), lesser-powered, short-lived, SOHC, three valves per cylinder M 137 V12 engine. Mercedes ceased production of the M 120 because of new emission rules.
This engine developed 394–408 PS (290–300 kW; 389–402 hp) and 420–428 lb⋅ft (569–580 N⋅m) of torque for the 6.0 L version. In 1992 only, the M 120 engine was offered in North America in 402 hp (300 kW; 408 PS) format and from 1991-92 408 PS (300 kW; 402 hp) in Europe. All other years (1993–1999) have the 394 PS (290 kW; 389 hp) version.
Applications:
A 7.1 litres (7,055 cc) version was also used in the SL 70 AMG, S 70 AMG and CL 70 AMG, and produced 365 kW (496 PS; 489 hp). Another 7.1 litres (7,055 cc) version with 380 kW (517 PS; 510 hp) was used for SL 72 AMG, S 72 AMG and CL 72 AMG cars.

There was also a 7.3 L version producing 525 PS (386 kW; 518 hp) developed by AMG which was used in the SL 73 AMG. The 7.3 L M 120 engine was also featured in the AMG-built, S 73 T Kombi, a custom-built W140 S-Class wagon for the Sultan of Brunei. Eighteen units were produced, ten of which went to the Sultan.
In 1997, the FIA GT Championship race car Mercedes-Benz CLK GTR was fitted with the M 297 engine, derived from the M 120. The 25 road cars, required by the FIA rules and delivered in 1999, had their engine enlarged to 6.9 L.
The Pagani Zonda has used three different capacities of Mercedes-AMG tuned versions of the M 120 engine, starting with the untuned 6.0 L for the original Zonda C12 to a 7.0 L version for the C12-S and Zonda GR, then to the 7.3 L for the Zonda S 7.3/Zonda Roadster, and back to the 6.0 L for the Zonda R and the Zonda Revolución. The bore and stroke of the 7.3 L version is 91.5 mm × 92.4 mm (3.602 in × 3.638 in).
Applications:
| Year | Model | Displacement | Power output |
|---|---|---|---|
| 1999 | Pagani Zonda C12 | 5,991 cc (6.0 L; 365.6 cu in) | 408 PS (300 kW; 402 hp) or 450 PS (331 kW; 444 hp) |
| 1999 | Pagani Zonda C12-S | 7,010 cc (7.0 L; 427.8 cu in) | 550 PS (405 kW; 542 hp) |
| 2002 | Pagani Zonda S 7.3 / Zonda Roadster | 7,291 cc (7.3 L; 444.9 cu in) | 555 PS (408 kW; 547 hp) |
| 2003 | Pagani Zonda GR | 7,010 cc (7.0 L; 427.8 cu in) | 600 PS (441 kW; 592 hp) |
| 2009 | Pagani Zonda R | 5,991 cc (6.0 L; 365.6 cu in) | 750 PS (552 kW; 740 hp) |
| 2012 | Pagani Zonda R Evoluzione | ||
| 2012 | Pagani Zonda Revolución | 800 PS (588 kW; 789 hp) | |
| 2014 | Pagani Zonda R "Revolución Specification" | 780 PS (574 kW; 769 hp) | |
| 2021 | Pagani Huayra R | 850 PS (625 kW; 838 hp) | |
| 2024 | Pagani Huayra R Roadster | 900 PS (662 kW; 888 hp) |