BMW X5: Engine, General

 Valvetrain

The valvetrain on the N52 introduced in 2006, used 5 mm valve stems on both the intake and exhaust. To increase durability, the exhaust valve stems were increased to 6 mm from 6/06 production. All of the new NG6 engine have adopted the 6 mm valve stem for the exhaust, the intake stem remains at

 Crankcase

As far as the physical appearance and dimensions, the crankcase on the N54 is the same as the N52. The main change is in the materials, the N54 uses an all aluminum alloy crankcase. There is also cast iron cylinder liners similar to the previous M54 engine. The reason for using the all aluminum c