ENGINE COMPONENTS / SYSTEMS OVERVIEW

The N55 engine is the successor to the N54. Re-engineering and modifications have

Made it possible to now use only one exhaust turbo charger. Against the backdrop of

Reduced costs and improved quality, the technical data have remained virtually the same.

The following provides an overview of the features of the N55 engine

CRANCASE

•       Large longitudinal ventilation holes inter-connect the crankcase lower chamber and relieve unwanted crankcase pressure between cylinders.
•            Modified oil galleries enhance the supply of oil to vacuum pump.
•      Crankshaft: Is light weight design and has an asymmetric counterweight arrangement.

PISTONS AND CONNECTING RODS

• A specially formed bushing/bore in small end of the connecting rods evenly distributes the force of the pistons on the power stroke.
• Lead-free bearing shells are installed on the big-end of the connecting rods cylinder head.
• Specially designed water passages intergraded into the cylinder head enhance Injector cooling.
• The combustion chambers are machined to work in conjunction with the valvetronic.
• III system with regard to promoting air turbulence and mixture formation.

CRANKCASE VENTILATION

•        In contrast to the N54, the N55 crankcase ventilation does not use cyclone separators.
•      The cylinder and head cover have integrated blow-by passages that connect the crankcase ventilation directly to the intake ports.

VANOS

• The N55 VANOS oil passages are simplified compared to the N54 engine.
• The solenoid valves have integrated non-return valve and 3 screen filters.
• The VANOS units are of a lightweight design for increased adjustment speed and have reduced susceptibility to soiling.

VALVE TRAIN

• The N55 is the first BMW turbo engine to incorporate valvetronic.
• The valve train is a new designed that combines valvetronic III with Double VANOS.
• With valvetronic III the 3rd generation brush less servomotor is introduced.
• The position detection sensor of eccentric shaft is now integrated in the servomotor 6 N55 Engine.