Valvetrain Assembly Overview

Valvetrain Assembly Overview

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





1 Sealing plug

2 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 => [ Valve Stem Seals, with Cylinder Head Removed ] Valve Stem Seals, With Cylinder Head Removed

3 Valve spring

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

4 Support element

• With hydraulic valve clearance compensation

• Clipped into roller rocker lever - item 8 -

• Checking, refer to => [ Support Elements with Hydraulic Adjustment, Checking ] Testing and Inspection

• Mark for re-installation

• Lubricate contact surface

5 Valve spring plate

6 Valve keys

7 Securing clip

• Check for secure seat

8 Roller rocker lever

• Mark for re-installation

• Check roller for easy movement

• Lubricate contact surface

• To assemble, clip onto support element - 4 - with securing clip - 7 -

9 Intake camshaft

• Removing and installing, refer to => [ Camshafts ] Removal and Replacement

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

• Measure radial clearance using Plastigage(R) (roller rocker lever removed)

• Radial clearance at bearing-dia. 24 mm: 0.024 to 0.066 mm

• Radial clearance at bearing-dia. 36 mm: 0.032 to 0.078 mm

• Run-out: maximum 0.04 mm

10 Gasket

• Replace

11 Bearing bracket

• With integrated camshaft bearings

• Removing and installing, refer to => [ Camshafts ] Removal and Replacement

12 Bolt

• Tightening order => [ Guide frame tightening sequence ]

13 Camshaft position (CMP) sensor 2 (G163)

14 Bolt

• 9 Nm

15 O-ring

• Replace

16 Bolt

• 9 Nm

17 Camshaft position (CMP) sensor 4 (G301)

18 O-ring

• Replace

19 Compression ring

• For camshaft adjuster

20 Exhaust camshaft

• Removing and installing, refer to => [ Camshafts ] Removal and Replacement

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

• Measure radial clearance using Plastigage(R) (roller rocker lever removed)

• Radial clearance at bearing-dia. 24 mm: 0.024 to 0.066 mm

• Radial clearance at bearing-dia. 36 mm: 0.032 to 0.078 mm

• Run-out: maximum 0.04 mm

21 Cylinder Head

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

22 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

23 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

Guide frame tightening sequence





- Tighten bolts in 2 stages in sequence - 1 to 24 - as follows.

- Install bolts by hand as far as stop.

- Tighten bolts to 8 Nm.

Installed position of valve spring





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