Engine Oil System
The oil supply system of the S62B50 engine is specifically designed for the M5 and Z8. Due to the sport nature and the ability for high speed cornering (transverse acceleration) of up to 1.2g, the engine oil could be forced (and trapped) into the outer edge of the cylinder head and the rear area of the oil sump.
The main oil pump function is to supply the engine with the required volume of oil for all of the lubrication needs.
To prevent oil starvation from occurring during these driving situations, two additional scavenging oil pumps are installed within the main oil pump housing (integral unit).
The two additional pumps only supply the oil sump with the scavenged oil.
Each additional oil pump incorporates a solenoid changeover valve that is connected to two scavenging tubes routed to the rear section of the oil pan and the outer edge of the cylinder head.
The scavenging tubes in the oil pan crossover so that the right side pump draws from the rear left side of the pan and the left pump from the right side of the pan.
The solenoid changeover valves must be removed before attempting to remove the oil pan. The valves insert directly into the scavenge pump housing through the oil pan.
The upper oil pan for the Z8 is been modified due to the engine and crossmember "clearance" relationship.
The upper oil pan is contoured around the oil pump drive at the front of the engine (arrow).
Scavenge Oil Pump(s) Operation: While driving straight ahead, the two oil pumps draw oil from the rear of the oil pan to supply the main oil pump pick up.
The solenoids are de-activated in this situation.
When cornering at forces > 0.9g, one solenoid will be activated by the ECM to draw oil from the cylinder head while the second solenoid will continue to draw oil from the rear of the pan.
The ECM receives the signal from the DSC Control Module (based on cornering G-force) over the CAN Bus line.
Oil Cooling: The S62 engine is equipped with an oil-to-coolant heat exchanger. It is mounted in the "V" of the block and serves to heat the oil during engine warm up and cool the oil during normal driving. Oil and coolant passageways are cast into the block. Formed "O" rings are used to seal the heat exchanger. The coolant return is through external pipes back to the thermostat housing.
A differential pressure control valve is integrated into the heat exchanger on the oil side. The valve opens an oil bypass in the event that the exchanger should become clogged or at very low start temperatures. This ensures that the engine will receive sufficient lubrication under all driving conditions.