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 => [ Valve Stem Seals, Replacing ] Service and Repair.
3 Valve spring
• Installed location => [ Installed position of valve spring ]
4 Support element
• With hydraulic valve clearance compensation
• Clipped into roller rocker lever - 8 -
• Checking => [ 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 => [ Camshafts ] Service and Repair
• Measuring axial play => [ Camshaft Axial Play, Measuring ] Testing and Inspection
• Measure radial clearance using Plastigage (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 => [ Camshafts ] Service and Repair
12 Bolt
• Tightening order => [ Bearing 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 => [ Camshafts ] Service and Repair
• Measuring axial play => [ Camshaft Axial Play, Measuring ] Testing and Inspection
• Measure radial clearance using Plastigage (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 => [ Valve Guides, Checking ] Testing and Inspection
22 Intake valve
• Do not rework, only lapping is permitted
• Mark installed position for re-installation
• Valve dimensions => [ Valve Dimensions ] Specifications
• Check valve guides => [ Valve Guides, Checking ] Testing and Inspection
23 Exhaust valve
• Do not rework, only lapping is permitted
• Mark installed position for re-installation
• Valve dimensions => [ Valve Dimensions ] Specifications
• Check valve guides => [ Valve Guides, Checking ] Testing and Inspection
Bearing frame tightening sequence
- Tighten bolts in 2 stages - 1 to 24 - in sequence 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.