The Mercedes-Benz M120 engine is a V12 automobile piston engine family used in the 1990s and 2000s.
The M120 family is built in Stuttgart, Germany. It has an aluminum engine block lined with silicon/aluminum. The aluminum 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 in Mercedes' V12 vehicle line-up by the smaller, lesser-powered, short-lived, SOHC, three valves per cylinder, 5.8L, M137 engine.
This engine developed 394 - 408 PS and 420–428 ft·lbf of torque for the 6.0 L version. In 1992 only the M120 engine was offered in North America in 402 hp (300 kW) format and from 1991-92 408 PS In Europe. All other years 1993-1999 have the 394 PS (290 kW) version.
Applications:
In 1997, the FIA GT Championship race car Mercedes-Benz CLK GTR was fitted with an engine derived from the M120. The 25 road cars, required by the FIA rules and delivered in 1999, had their engine enlarged to 6.9L.
There was also a 7.3L version producing 525 hp (391 kW) developed by AMG which was also used in the SL73 AMG. 7.2L version exists as well. And there was a 7.0L version producing 496 hp (370 kW) used in the very rare SL70 AMG.
The 7.3L M120 engine was also featured in the AMG-built, S73 T Kombi, a custom-built, W140, S-Class wagon built for the Sultan of Brunei. Eighteen units were produced, ten of which went to the Sultan.
The Pagani Zonda has used 3 different capacity, 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 C12s 7.3, Zonda F, Zonda Cinque and the Zonda Tricolore, and back to the 6.0 L for the Zonda R and the Zonda Revolucion. The bore and stroke is 91.5mm and 92.4 mm.