BMW 3: IROX coating - Crankshaft drive
Detailed magnification of the IROX coating
- IROX-coated bearing shell
- Oil film
- IROX coating
- Bearing shell
- Binding resin
- Hard particle
- Solid lubricant
The IROX coating is applied to a conventional bearing shell. It consists of a binding resin matrix made of polyamide-imide with embedded hard particles and solid lubricants. The polyamide-imide ensures, in combination with the hard particles, that the bearing shell surface is so hard that material abrasion is no longer possible. The solid lubricants reduce surface friction and replace the oil film which briefly no longer exists between the bearing shell and the connecting rod bearing journal during the starting phase. The IROX bearings are red due to their special coating.
The IROX-coated bearing shells are only located on the connecting rod side as here the load acts mainly on the bearing shells. The bearing shell caps are equipped with a bearing shell without IROX coating.
If a connecting rod bearing cap is mounted the wrong way round or on another connecting rod, the fracture structure of both parts is destroyed and the connecting rod bearing cap is not centered. In this event the entire set of connecting rods must be replaced with new parts. In Service please observe the specified jointing torques and angle of rotation specifications in the repair instructions.
Bearing shell classification of connecting rod bearing
The connecting rod bearing shells are available in one standard size. It is therefore not necessary to follow a procedure similar to that used with the main bearing shells of the crankshaft.
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Chain drive - Crankshaft drive
Features:
Chain drive at the side of the engine emitting the forces.
Single-part chain drive for driving the camshafts.
Single sleeve-type chain 8 mm.
Electric motor of the combined oil-vacu
Chain tensioner
Chain tensioner
Tensioning rail
Sealing sleeve
Chain tensioner with screw thread
Due to the cylinder head manufacturing process, the chain tensioner now has a
sealing sleeve with a
height of 12
Valve gear
VANOS
VANOS unit B46 engine and B46TU/B48TU engines
VANOS B46 engine
VANOS B46TU and B48TU engine
Following the changeover from a two-part chain drive to a single-part chain
drive, the camshaft
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Intelligent Safety
Concept
Intelligent Safety enables central operation of the
driver assistance systems.
General information
Depending on how the vehicle is equipped, Intelligent
Safety consists of one or more systems
that can help prevent an imminent collision.
Front collision mitigation.
Evasion Assistant.
Inte
Snow chains
Safety information
Warning
With the mounting of snow chains on unsuitable
tires, the snow chains can come into contact
with vehicle parts. There may be a risk of
accident or risk of damage to property. Only
mount snow chains on tires that are designated
by their manufacturer as suitable for the use
