Mercedes-Benz M156 V8 engine
The M156 engine had a 102.2 mm bore and a 94.6 mm stroke for a capacity of 6208 cc. Despite its capacity of, the engine was marketed as ‘6.3’ to commemorate the Mercedes-Benz M100 engine which initially displaced 6.3-litres. Significantly, the M156 engine had a high-strength aluminium-silicon alloy (AlSi7) block that was designed with a rigid bedplate at the main bearings, cast-in steel reinforcements and a closed-deck layout beside the aluminium-silicon alloy (AlSi17) cylinder head.
Other attributes of the M156 engine included Cromax 42CrMo4V forged steel alloy crankshaft, fracture-split forged connecting rods, cylinder bores with twin-wire-arc-sprayed (TWAS) coating, Bosch 9.7 engine management system, double overhead camshafts per cylinder bank (intake cams driven by a double chain from the crankshaft and small gears on the intake cams drive the exhaust camshafts), continuously variable intake and exhaust camshafts (over a range of 40 degrees via electrohydraulic vane-type adjusters), four valves per cylinder (40 mm intake valves and 34 mm exhaust valves), bucket tappets, a magnesium variable intake manifold (with two electrically-operated internal flaps) and compression ratio of 11.3:1.
For the E 63 AMG, maximum engine speed was in excess of 7000 rpm, yet 90 per cent of peak torque was available from 2000 rpm.
| Engine | Engine code | Peak power | Peak torque | Model |
|---|---|---|---|---|
| M156 E 63 | 156.985 | 336 kW at 6800 rpm | 600 Nm at 5000 rpm | W204 C 63 AMG |
| 358 kW at 6800 rpm | 600 Nm at 5000 rpm | W204 C 63 AMG (Performance) |
||
| 156.982 | 354 kW at 6800 rpm | 630 Nm at 5000 rpm | C209 CLK 63 AMG | |
| 373 kW at 7200 rpm | 630 Nm at 5250 rpm | C209 CLK 63 AMG Black Series | ||
| N/A | 373 kW at 6800 rpm | 610 Nm at 5000 rpm | W204 C 63 AMG Edition 507 | |
| 156.980 | 375 kW at 6800 rpm | 630 Nm at 5200 rpm | W164 ML 63 AMG | |
| 630 Nm at 5200 rpm | W251 R 63 AMG | |||
| 156.983 | 378 kW at 6800 rpm | 630 Nm at 5200 rpm | C219 CLS 63 AMG | |
| 378 kW at 6800 rpm | 630 Nm at 5200 rpm | W211 E 63 AMG | ||
| N/A | 380 kW at 6800 rpm | 620 Nm at 5200 rpm | C204 C 63 AMG Black Series | |
| 156.984 | 386 kW at 6800 rpm | 630 Nm at 5200 rpm | C216 CL 63 AMG | |
| W221 S 63 AMG | ||||
| R230 SL 63 AMG | ||||
| W212 E 63 AMG |
M156 problems: camshaft lobe and valve lifter wear
In a US class action – CEDRIC CHAN v. DAIMLER AG, MERCEDES-BENZ, MERCEDES-BENZ USA, LLC and MERCEDES-AMG GMBH – it was alleged that the combination of nodular cast iron camshafts and valve lifters made of 9310-grade steel resulted in premature wear of the M156 engine as a result of:
- the soft camshaft metal, and/or
- improper heat treating, and/or
- improper camshaft offset.
Specifically, the camshafts were designed so that the lobes would contact the valve lifters. When the camshaft lobes experienced wear, the surface would become rough or scored and no longer make contact with the lifters with the same precision – this would cause the lifters to wear prematurely, demonstrated by a gouged ring in the top of the valve lifter. The gouged ring wear on the buckets also indicated that the buckets were not spinning as intended. The result of this premature wear would be serious engine failure.
Symptoms of camshaft lobe and valve lifter wear include rattling or clattering noises on start-up. In service bulletin S-B 05.20/20b (produced in 2009), Mercedes-Benz acknowledged that problem of camshaft and valve tappet wear. Ultimately, the class action did not proceed due to the plaintiffs’ lack of standing.
Mercedes-Benz M156 engine development
Mercedes-Benz M156 engine production explained
Mercedes-Benz M156 engine production – extended video
Mercedes-Benz M159 V8 engine
Released in 2009, the M159 engine was an evolution of the M156 unit that was used in the Mercedes-Benz SLS AMG. Changes included revised valve train and camshaft (with a 42 degree range of adjustment), and a more flow-efficient design of the intake air ducting for reduced pressure losses. The M159 engine also introduced flow-optimised tubular steel headers and dry-sump lubrication.
| Engine | Peak power | Peak torque | Model |
|---|---|---|---|
| M159 E 63 | 420 kW at 6800 rpm | 650 Nm at 4750 rpm | C197 SLS AMG Coupe, R197 SLS AMG Roadster |
| 435 kW at 6800 rpm | 650 Nm at 4750 rpm | C197, R197 SLS AMG GT | |
| 464 kW at 7400 rpm | 635 Nm at 5500 rpm | C197 SLS AMG Black Series |
