Mercedes M278 4.6L Engine Specs, Problems, Reliability. The Mercedes-Benz M278 is a 4.6-liter V8 direct-injected bi-turbo engine presented in 2010. This member of the new engine household, which likewise includes the M276 V6, changed the previous M273 V8 engines under a hood of the popular E-Class, S-Class, and GL-Class designs.
The M278 is based on a 4.7-liter version of the M273. Both engines share the very same die-cast complete aluminum cylinder block with 90-degree V-angle and Silitec low-friction cylinder liners. Bore size, stroke, and bore pitch equal. The M278 has brand-new pistons with increased by 2 mm compression height. The linking rods in opposite are 2 mm shorter in order to preserve a compression ratio of 10.5:1. At the bottom, there is a two-piece die-cast aluminum oil pan. The crankshaft drives a brand-new vane-type regulated oil pump via a simplex bush roller chain and a chain-drive integrated equipment of the two-stage chain drive system via a main timing chain.
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Mercedes M278 4.6L Engine Specs, Problems, Reliability
Each cylinder bank is equipped with an aluminum cylinder head with 4 valves per cylinder and 2 overhead camshafts. The intake and exhaust camshafts are driven by a chain-drive integrated gear through a secondary timing chain (there are two of them, by one for each head). Each camshaft is geared up with the hydraulic vane-cell adjusters of the variable valve timing system, which has an increased modification variety compared to the M273.
The M278 engine likewise includes the third-generation direct injection system with piezo injectors (several injections during a combustion cycle) and multi-spark ignition. The high-pressure pump is located at the rear end on the right intake camshaft and drives by 4 additional cameras. The pressure provided to the rails lies in between 120 and 200 Bar.
Like the predecessor, the M278 4.6 L V8 is a turbocharged engine. Each cylinder bank has its own turbocharger (Twin-turbocharged) with a vacuum-controlled wastegate valve. These little Honeywell turbochargers produce as much as 0.9 bar (13 psi) improve pressure. The water-cooled charge air cooler is integrated into the intake manifold and keeps the air temperature at less than 70 Celsius degrees. Engine systems are controlled by the MED17.7 engine control unify (ECU).
Mercedes replaces the outbound M278 V8 engine range with the latest 4.0-liter M176 engine series introduced in 2015.
Mercedes M278 Engine Problems and Reliability
Early construct M278 V8s had some problems with the timing chain tensioners triggering a rattle on launch. The engine has a pretty complex timing chain drive plan. It includes one primary chain and two secondary chains, and each of them is equipped with tensioner (3 overall). If not take note of knocks/noise for a very long time, this may lead to the replacement of the entire chain drive system together with webcam adjusters. There were some reports of engine oil hunger due to the failure of the oil pump drive gear (oil pump is driven through a chain).
There were some problems with early valve guide wear, but later on engines do not have that concern. The Silitec covering showed themselves as bad cylinder surface product for operation under high temperatures and detonation. Later on, the producer switched on NanoSlide coating which is more scratch resistance.
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Mercedes M278 4.6L Engine Specs
| Manufacturer | Daimler AG |
| Production years | 2010-present |
| Cylinder block material | Aluminum |
| Cylinder head material | Aluminum |
| Fuel type | Gasoline |
| Fuel system | Direct Injection |
| Configuration | V |
| Number of cylinders | 8 |
| Valves per cylinder | 4 |
| Valvetrain layout | DOHC |
| Bore, mm | 92.9 mm (3.66 in) |
| Stroke, mm | 86 mm (3.39 in) |
| Displacement, cc | 4,663 cc (284.6 cu in) |
| Type of internal combustion engine | Four-stroke, turbocharged |
| Compression Ratio | 10.5:1 |
| Power, hp | 367-435 hp (270-320 kW)/5,250 |
| Torque, lb ft | 406-516 lb-ft (550-700 Nm)/1,600-3,500 |
| Engine weight | – |
| Firing order | 1-5-4-2-6-3-7-8 |
| Engine oil weight | MB 229.5/229.51, SAE 0W-40 |
| Engine oil capacity, liter | 8.5l (9.0 qt) |
| Oil change interval, mile | 9,000 (15,000 km) / 12 months |
| Applications | Mercedes-Benz S-Class (S500/S550), Mercedes-Benz CL-Class (CL500/CL550), Mercedes-Benz S-Class Coupe/Cabriolet (S500/S550), Mercedes-Benz CLS-Class (CLS500/CLS550), Mercedes-Benz SL-Class (SL500/SL550), Mercedes-Benz E-Class (E500/E550), Mercedes-Benz M-Class/GLE-Class (ML500/GLE500/ML550), Mercedes-Benz GL-Class (GL450), Mercedes-Benz GLS-Class |
