BMW E60 Engine (N52)

The BMW E60  N52 is a straight-6 DOHC piston engine. Compared to its M54 predecessor, the N52 features variable valve lift aka Valvetronic by BMW and also Dual VANOS, a continuous variable valve timing control for both inlet and exhaust camshafts.

The N52 crankcase is made entirely of magnesium and aluminum.

The N52 engine block is cast with magnesium and aluminum for the crankcase. Magnesium is used to save weight but magnesium is subject to a greater risk of corrosion from water. However, magnesium may tend to creep under load at high temperatures. Thus, magnesium in its pure form or as a conventional alloy is not suited for permanently conveying high loads and forces of the kind typically encountered in central components of the engine. Therefore, BMW combined the N52 block to use magnesium alloy for the crankcase shell, with an aluminum “inner block” to complement the magnesium disadvantages.

For the cylinder liners the N52 Engine uses Alusil to coat the aluminum cylinder sleeves. Alusi is an aluminium alloy commonly used to make linerless aluminium alloy engine blocks. Alusil, when etched, will expose a very hard silicon precipitate. BMW switched from Nikasil-coated cylinder walls to Alusil to eliminate the corrosion problems caused through the use of petrol or gasoline containing sulphur.