Valvetrain Assembly Overview

Valvetrain Assembly Overview

• Cylinder head for cylinder bank 2 (left) is shown in illustration.





1 Sealing plug

• Install with sealant; sealant

2 Cylinder Head

• Check valve guides, refer to => [ Valve Guides, Checking ] Testing and Inspection

3 Valve stem seal

• Replacing with the cylinder head installed, refer to => [ Valve Stem Seals, Cylinder Head Installed ] Valve Stem Seals, Cylinder Head Installed

• Replacing with the cylinder head removed, refer to => [ Valve Stem Seals, with Cylinder Head Removed ] Valve Stem Seals, With Cylinder Head Removed

4 Valve spring

• Installed location => [ Installed position of valve spring ]

5 Hydraulic adjusting elements

• Checking, refer to => [ Hydraulic Adjusting Elements, Checking ] Testing and Inspection

• Mark the installation position with paint for reinstallation

• Lubricate the running surfaces before installing

6 Valve spring plate

7 Valve keys

8 Roller rocker lever

• Different versions for the intake and exhaust side, do not interchange them

• Check roller for easy movement

• Lubricate the running surfaces before installing

• Clip to the hydraulic adjusting element - 5 - with the clip - 9 -

9 Securing clip

• Different versions for the intake and exhaust side, do not interchange them

• Check for secure seat

10 Intake camshaft

• With 3 camshaft sliders

• Do not disassemble

• Measuring axial play, refer to => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play

• Removing and installing, refer to => [ Camshafts ] Service and Repair

• Radial clearance, measuring, refer to => [ Camshaft, Measuring Radial Play ] Camshaft, Measuring Radial Play

• Maximum run-out: 0.04 mm

11 Bolt

• Replace

• Tightening order => [ Camshaft guide frame tightening specifications
and sequence ]

12 Camshaft adjuster actuator

13 Bolt

• 5 Nm

14 O-ring

• Replace

15 Bearing bracket

• With integrated camshaft bearings

• Removing and installing, refer to => [ Camshafts ] Service and Repair

16 Compression ring

17 Compression ring

18 Exhaust camshaft

• Measuring axial play, refer to => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play

• Removing and installing, refer to => [ Camshafts ] Service and Repair

• Radial clearance, measuring, refer to => [ Camshaft, Measuring Radial Play ] Camshaft, Measuring Radial Play

• Maximum run-out: 0.04 mm

19 Oil strainer

20 Intake valve

• Do not rework, only lapping is permitted

• Mark installed position for re-installation

• Valve dimensions, refer to => [ Valve Dimensions ] [1][2]Specifications

• Check valve guides, refer to => [ Valve Guides, Checking ] Testing and Inspection

21 Exhaust valve

• Do not rework, only lapping is permitted

• Mark installed position for re-installation

• Valve dimensions, refer to => [ Valve Dimensions ] [1][2]Specifications

• Check valve guides, refer to => [ Valve Guides, Checking ] Testing and Inspection

Camshaft guide frame tightening specifications and sequence





• The illustration shows the guide frame for the left cylinder head.

- Replace the guide frame bolts.

- Tighten the bolts in 3 stages in the sequence - 1 to 21 -:

- Install bolts by hand as far as the stop.

• The guide frame must be in contact with the entire contact surface of the cylinder head.

- Tighten to 8 Nm.

- Tighten an additional 90°.

Installed position of valve spring





• The tight spring coils - arrow - face toward the cylinder head.