The high performance BMW S62 engine was made for the E39 M5 and the BMW E52 Z8. The engine is a 4.9 L (4,941 cc and 301.5 cu in) V8 Engine based on the same architecture as the all aluminium block 4.4 and 4.6L BMW M62 motor found in the E39 540i and M53 4.4 and 4.6 engines. BMW Motorsport ‘M’ Division has extensively developed and modified the engine accordingly for increased all round power as proven on race tracks and dynamometers around the world today.
The M5's engine features an aluminum and silicon alloy sand cast 'Alusil' engine block. The cylinder block piston sleeves walls are etched after a special honing process to promote oil retention and reduce friction. The S62 V8 block shares the M62 basic configuration and architectural design of it’s 4.4 and 4.6 engined brothers, but with 94 mm cylinder bores compared to the M62, 92mm and 93 mm bores. The stroke was increased from 82.7 mm and 85mm to 89 mm significantly improving the torque curve of the engine from the bottom end. This increase in stroke increased the displacement to 4941 cc or 301.5 cubic inches.
The cylinders are narrowly placed together with only 4 mm of block surface between cylinders. BMW engineers developed a 3x layered steel variant head gasket to ensure a better seal at higher performance levels due to the Siamesed oversized cylinder bores.
Based on the cylinder heads used in other BMW V8 engines, the M5's heads were completely redesigned with new jackets for cross-flow cooling. The intake side of the cylinder heads also got newly designed coolant passages to help keep the larger pistons cool as this was an all out hi-performance engine designed for the BMW enthusiast that was taken to the race tracks.
The air induction system is taken in at two points behind the front bumper, passes through two intake silencers and two hot-film air-mass meters, and then flows into the voluminous plenum at the top of the engine. The air courses through 230 mm-long intake runners and 230 throttle housings to the individual cylinders. The entire assembly of plenum and runners is attached to the throttle housings via a rubber and metal flange on either side of the cylinder banks that decouples the plenum from the engine itself. This is how the engine is helped to be kept cooler before the air fuel mixture passes into the combustion chambers through eight individual throttle butterflies, each 48.2 mm in diameter, one throttle body for each cylinder. The S62 was the first BMW engine with electronically actuated individual throttles with each throttle mounted directly above the intake port.
The S62 is BMW's first V8 engine equipped with Double VANOS a system that steplessly varies the cam timing of both intake and exhaust valves of both left and right cylinder banks. As on other BMW engines, the VANOS cam timing mechanisms are located at the front of the cylinder heads. The 100 bar hydraulic pressure used to actuate VANOS is produced by two oil pumps, one for each cylinder head. Valve timing is varied over a range of 60 degrees in terms of crankshaft rotation with a wider adjustment range than that of other BMW V8 engines.
A forged five-main bearing crankshaft with counterweights receives Mallory metal plugs for extremely fine balance and all 8 conrods are forged as one piece. The connecting rod caps are then fracture split for the best possible fit when being installed. Balancing pads are also placed on both small and large ends of the rods for perfect end to end balancing.
Piston design is unique to the S62 motor. For optimum power output, engineers designed specifically shaped cutouts in the piston crowns for the intake and exhaust valves. This requires a different piston design for each cylinder bank, rather than the usual identical design for all eight pistons. Pistons are cooled by two upward-firing oil jets in each cylinder as per the M62B46 engine. The oil jets are indexed to oil pressure and when pressure reaches 2.5 bar they begin squirting. The compression ratio is 11.0:1
Other significant features of the cylinder heads include hollow camshafts of nodular cast iron for reduced inertia. The S62's 35 mm intake and 30.5 mm exhaust valves are shared with the M62 engine, but valve timing is unique. The intake cam profiles yield 10.32 mm (0.406 in) valve lift and 252 degrees total duration and the exhaust cam profiles yield 10.2 mm (0.402 in) lift and 248 degrees duration.
In place of the M62 engine's simplex or sinle row roller chain driving both intake camshafts, the S62 employs a heavy duty duplex or double roller chain driving each intake camshaft. As with the M62 engines, the two secondary single row chains drive the exhaust camshafts from the intake camshafts and visa versa.
The S62 engine revs to a limited 7000 RPM producing 294 kW or 394 hp at 6600 rpm and 500 N·m of torque at 3800 rpm. The engine is easily identified by its large intake velocity stack chamber cover that carries the "M" logo with "BMW M Power" badged against a carbon fiber background.