Mercedes-Benz M120 engine
Overview
Manufacturer	Mercedes-Benz
Layout
Configuration	Naturally aspirated 60° V12
Displacement	6.0 L (5,987 cc) 7.0 L (7,010 cc) 7.1 L (7,055 cc) 7.3 L (7,291 cc)
Cylinder bore	89 mm (3.5 in) 91 mm (3.6 in) 91.5 mm (3.60 in)
Piston stroke	80.2 mm (3.16 in) 90.4 mm (3.56 in) 92.4 mm (3.64 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	Mercedes-Benz M154 engine
Successor	Mercedes-Benz M137 engine

The Mercedes-Benz M120 engine is a naturally aspirated high-performance automobile piston V12 engine family used in the 1990s and 2000s in Mercedes' 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 (220 kW), Mercedes-Benz upped the ante considerably by creating a 6-litre, 300-kilowatt (408 PS) engine.^[1]

The M120 family is 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 M120 was eventually replaced by the smaller (5.8 litres), lesser-powered, short-lived, SOHC, three valves per cylinder M137 V12 engine. Mercedes ceased production of the M120 because of new emission rules.

M120 6.0 48v

M120 S600 (1994), 400 PS (294 kW; 395 hp)

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 M120 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:

• 1991–1998 600 SE / 600 SEL / S 600
• 1992–1999 600 SEC / S 600 Coupé / CL 600
• 1992–2001 600 SL / SL 600
• 2004 Chrysler ME-412
• 2014–2022 Hongqi L5
• 1993 (1995?) Isdera Commendatore 112i
• 2005 Laraki Borac
• 2003 Laraki Fulgura
• 2000 Lotec Sirius (with twin-turbo version of M120 engine)
• 1996–1999 Mega Monte Carlo
• 1992–2000 Mega Track

Larger displacement M120s

In 1997, the FIA GT Championship race car Mercedes-Benz CLK GTR was fitted with the M297 engine, derived from the M120. The 25 road cars, required by the FIA rules and delivered in 1999, had their engine enlarged to 6.9 L. There was also a 7.3 L version producing 525 PS (386 kW; 518 hp) developed by AMG which was also used in the SL73 AMG, S73 AMG and CL73 AMG. The 7.3 L M297 engine was also featured in the AMG-built, S73 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.^[2]

A 7.1 L (7,055 cc) version was also used in the SL70 AMG, S70 AMG and CL70 AMG, and produced 496 PS (365 kW; 489 hp).

Another 7.1 L (7,055 cc) version with 510 PS (380 kW; 500 hp) was used for SL72 AMG, S72 AMG and CL72 AMG cars.

Pagani Zonda

The Pagani Zonda^[3] has used three different capacities of Mercedes-AMG tuned versions of the M120 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, Zonda F/Roadster F, Zonda Cinque/Cinque Roadster, Zonda Tricolore and back to the 6.0 L for the Zonda R and the Zonda Revolución. The bore and stroke is 91.5 mm × 92.4 mm (3.60 in × 3.64 in).^{[4][5][6][7][8][9][10][11]}

Applications:^[12]

AMG engine display at the Pagani factory

References

See also

Wikimedia Commons has media related to Mercedes-Benz M120 engine.

• List of Mercedes-Benz engines