Mercedes-Benz M120 engine

Mercedes-Benz M 120 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 (3.504 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.¹

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.²

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:

• 1991–1998 600 SE / 600 SEL / S 600 (W140)
• 1992–1999 600 SEC / S 600 Coupé / CL 600 (C140)
• 1992–2001 600 SL / SL 600 (R129)
• 1991 C112 Concept
• 2004 Chrysler ME-412
• 1993 Isdera Commendatore 112i
• 2005 Laraki Borac
• 2003 Laraki Fulgura
• 2000 Lotec Sirius (with twin-turbo version of M 120 engine)
• 1996–1999 Mega Monte Carlo
• 1992–2000 Mega Track

A 7.1 litres (7,055 cc) version was also used in the SL3 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.³ 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.⁴

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).⁵⁶⁷

Applications:⁸

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  Pagani Zonda F engine
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  Pagani Zonda F engine
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  Pagani Zonda R engine bay