Cylinder Head: Notes

The cylinder head features the injector and spark plugs arranged in the center of the combustion chamber. The layout of the high pressure fuel pumps is similar to that on the N63 engine; however because of the conventional cylinder head arrangement (intake side on the inside, exhaust side on the outside) they are located above the intake camshafts (respectively between cylinders 1 and 2 and 7 and 8).

As on the N63 engine, the intake port features a trailing edge (around the valve seats) for creating more intensive charge movement.

Coolant flows diagonally across the cylinder head (from the outer side of the engine towards the V chamber), whereby the inlet is at the outside rear and the outlet at the inside front. This is referred to as diagonal cooling.

As on the N63 engine, only one non-return valve for the oil circuit is incorporated into the cylinder head. The N74 uses two VANOS non-return valves, they are now integrated into the VANOS solenoid valves.