Mercedes-Benz / AMG
M 273
Manufacturer:	Mercedes-Benz / AMG
Production period:	since 2005
Style:	V , eight-cylinder
Engines:	4.7 liters (4663 cc)  5.5 liters (5461 cc)
Previous model:	M 113
Successor:	M 278
Similar models:	M 272

The Mercedes-Benz M 273 Motor is a petrol engine with eight cylinders in V-arrangement .

The M 273 is the further development of the M 113 . From him he took over cylinder spacing and arrangement. This is technically related to the V6 cylinder gasoline engine M 272 , which originated in the same development cycle. The engines share above all the angle of the two cylinder banks to each other and the distance between the individual cylinders.

The M 273 debuted in September 2005 in the S-Class . Since then, the engine has been used in the E-Class and CLS , in the S and R Class , and also in the CL , SL and CLK , as well as the ML , GL and GSUVs . Successor from 2010 the engine M 278 .

Technical data

• liquid-cooled V8 four-stroke gasoline engine, 90 ° cylinder bank angle
• Cylinder distance: 106 mm
• Aluminum - engine block with cast-in cylinder liners made of Silitec (an Al - Si - alloy )
• five main bearings, forged steel - crankshaft , induction hardened connecting rod - and main bearings
• Forged Crack connecting rod made of 70MnVS4
• Aluminum crankcase with reinforced bearing caps and spray-compacted liners (weight 33 kg)
• Aluminum cylinder heads , each with two overhead camshafts ( DOHC ), phaser and central spark plug
• independent camshaft adjustment (designed as a vane-type adjuster ) for the intake and exhaust side
• Drive the two intake camshafts via 8 mm duplex bushing , exhaust camshaft via gears driven by the intake camshaft
• four valves per cylinder
• Tumble flaps in the inlet channels
• Compression ratio: 10.7: 1
• oval HFM (hot-film air mass meter , 15% less pressure loss than its predecessor)
• variably adjustable, variable intake manifold ( intake manifold ) of aluminum - magnesium - alloy
• electrically heated 3-plate thermostat (thermal management with map control)
• secondary air
• Bosch ME9 engine control unit with two microcontrollers (56 MHz, 2 MB flash memory)
• eight single-coil coils with pressed iron powder core and integrated driver electronics in direct arrangement above the spark plug
• 90% of the maximum torque is available between 2000 and 5600 rpm
• Weight according to DIN 70020a: 187 kg

Problems 

Basically, this engine is considered extremely reliable.At the same time, early models (until about September 2006) had problems with a deflection gear in the chain drive of the timing chain . Mercedes-Benz used unsuitable hardened material up to that date. As a result, the entire chain drive had to be swapped regularly for affected vehicles. According to Mercedes-Benz from the engine number 088611 a modified spur gear was installed. 

Also, the intake manifold made problems. The plastic flaps used therein, which are intended to vary the length of the intake, can coke over time and in extreme cases break off.

Performance increase 

In addition to a pure electronics optimization , the result of most providers with 316 kW (430 hp) specify and in various test reports to a significant improvement in acceleration to 200 km / h (up to about 3 s shorter acceleration times)  , more complex conversions with other camshafts and valve springs are available (about 460 hp). 

There are also manifolds available, but may not be operated within the scope of the road traffic licensing regulations. Their installation will invalidate the operating permit for the relevant vehicle. In addition, a deterioration caused by the installation of the exhaust emissions of the engine can lead to the fulfillment of a tax offense existence.

M 273 KE 46 

M 273 KE 55