BMW 3 Owners & Service Manuals

BMW 3: IROX coating - Crankshaft drive

Crankshaft drive
Detailed magnification of the IROX coating

  1. IROX-coated bearing shell
  2. Oil film
  3. IROX coating
  4. Bearing shell
  5. Binding resin
  6. Hard particle
  7. 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.


     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


     Overview of charging options

    The high-voltage battery unit of the G20 PHEV can generally only be charged by alternating current (AC charging) at a maximum charging power of 3.7 kW. The charging option for the high-voltage battery unit in the G20 PHEV is generally determined by the country-specific charging inf


    Concept The air flow directions can be individually adjusted. Adjusting the ventilation General information The air flow directions can be adjusted for direct or indirect ventilation. Open the vents and position them to ensure effective climate control. Direct ventilation The air flow is directed t

    © 2019-2024 Copyright