Mercedes-Benz M113 engine (1997-2012)

The Mercedes-Benz M113 was a V8 petrol engine that was introduced in 1997 to replace the M119 engine. The standard M113 engines were manufactured in Untertürkheim, Germany, though the AMG versions were assembled in Affalterbach, Germany.

Closely related to the M112 V6 petrol engine, the M113 engine had cylinder spacing of 106 mm, a 90-degree ‘V’ cylinder configuration, sequential fuel injection, an alloy cylinder block with cast-in Silitec (Al-Si-alloy) cylinder liners, fracture-split forged steel connecting rods, iron-coated aluminium pistons, an alloy cylinder head, a single overhead camshaft (SOHC) per cylinder bank (driven by a double-roller chain), two spark plugs per cylinder and a magnesium dual-length intake manifold.

The M113 engine had two intake valves and one exhaust valve per cylinder that were actuated by roller rockers. The use of one exhaust valve per cylinder was chosen to minimise heat losses when cold and enable the catalytic converter to reach its operating temperature faster. On the crankshaft in the cylinder V, a seated balancer shaft rotated opposite to the crankshaft at the same speed to balance first-order rocking motions.

The 4966 cc M113 E 50 engine was available with a cylinder deactivation system which enabled two cylinders on each bank to be shut down when the engine was under low loads and operating at a speed of less than 3500 rpm. In doing so, the engine provided greater fuel economy by reducing throttle losses and higher effective compression.

The M113 engine was replaced by the M273, M156 and M152 engines.

M113 E 43 AMG Engine

Used for the W202 C 43 AMG and S202 C 43 AMG Estate, the M113.944 V8 engine was assembled by AMG. Compared to the standard Mercedes-Benz engine, changes for the AMG version included:

• ‘Composite’ camshafts which were individually forged;
• A double-fluted intake system;
• A larger intake manifold; and,
• A unique exhaust system with larger pipes and a modified muffler system to minimise exhaust gas back pressure.

M113 E 55 Supercharged AMG engine

Used in the W211 E 55 AMG, the supercharged M113 E 55 ML engine had a Lysholm-type IHI supercharger – positioned between the cylinder banks – which provided maximum pressure of 0.8 bar and had an integrated air-water charge air cooler. The supercharger had two Teflon-coated aluminium shafts which rotated at up to 23,000 rpm, pushing 1850 kg of air per hour into the combustion chambers. To minimise fuel consumption at part throttle applications, the scroll compressor only operated at certain engine speeds and load conditions, activated by an electromagnetic coupling and a separate poly-V-belt.

Other changes for the supercharged M113 E 55 engine included

• A reinforced crankcase with stiffening ribs and side bolts;
• A precision-balanced crankshaft with modified bearings and a more resistant material;
• Unique pistons;
• Forged connecting rods;
• A revised oil supply system (including the sump, catch tray and pump) and a separate oil cooler in the right-hand wheel arch;
• Optimised cylinder heads;
• A twin-spring assembly for the valve train to increased maximum engine speed to 6100 rpm (from 5600 rpm);
• A redesigned fuel system;
• A twin-pipe exhaust system with switchover valve and 70 mm diameter tailpipes for reduced exhaust gas back-pressure; and,
• A unique engine management system.

^*SLK 55 AMG Black Series