Camshaft, Lifters and Push Rods: Service and Repair

Valvetrain Overview

• The cylinder head and the cylinder head cover must be replaced together.

• Do not start the engine for approximately 30 minutes after installing the camshafts. The hydraulic lash adjusters must seat themselves (otherwise the valves will seat themselves on the pistons).

• After working on the valvetrain and roller rocker arms, carefully rotate the crankshaft by hand at least 2 full revolutions before starting to be sure that the valves do not strike the pistons.

• Always replace the gaskets and seals.






1 Exhaust Valve

• Do not grind, only hand lapping is permitted.

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

• Checking the valve guides, refer to => [ Valve Guide, Checking ] Testing and Inspection.

2 Cylinder Head

3 Valve Guide

• Checking, refer to => [ Valve Guide, Checking ] Testing and Inspection.

4 Valve Stem Seal

• Removing and installing, refer to => [ Valve Stem Seals ] Service and Repair.

5 Valve Spring

6 Spring Plate

7 Valve Retainers

8 Roller Rocker Arm with Hydraulic Lash Adjuster

• Do not interchange.

• Lubricate the contact surfaces.

9 Exhaust Camshaft

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

• Checking the axial play, refer to => [ Camshaft Axial Clearance, Checking ] Testing and Inspection.

• Check the radial clearance using Plastigage(R) (roller rocker arm removed).

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

• Radial clearance at bearing - 32 mm diameter: 0.030 to 0.051 mm.

• Run out: maximum 0.04 mm.

10 Cylinder Head Cover

• With integrated camshaft bearings.

• Clean the sealing surface, reworking is not permitted.

• Remove any old sealant residue.

11 Bolt

• Always replace.

• Tightening sequence and specification, refer to => [ Cylinder Head Cover Bolt Tightening Sequence and Specification ].

12 Ball Stud

• 5 Nm

• With a ball head for the engine cover.

13 O-ring

• Always replace.

• Lubricate with engine oil.

14 Sealing Plug with O-ring

• Always replace.

• Oil the O-ring with engine oil.

15 Intake Camshaft

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

• Checking the axial play, refer to => [ Camshaft Axial Clearance, Checking ] Testing and Inspection.

• Check the radial clearance using Plastigage(R) (roller rocker arm removed).

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

• Run out: maximum 0.04 mm.

16 Cap

• Always replace.

• Removing: With the cylinder head cover installed, pierce through one side of the cover with an awl and pry it out.

• Installing: Without sealant, press in 1 to 2 mm using the thrust piece (T10174)

17 Intake Valve

• Do not grind, only hand lapping is permitted.

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

• Checking the valve guides, refer to => [ Valve Guide, Checking ] Testing and Inspection.

Cylinder Head Cover Bolt Tightening Sequence and Specification





Special tools, testers and auxiliary items required

• Torque Wrench (5-50 Nm) (V.A.G 1331)

Procedure

- Tighten the new cylinder head cover bolts in 3 passes in sequence - 1 through 6 - as follows:

- Tighten the bolts by hand.

- Tighten the bolts to 8 Nm.

- Tighten the bolts an additional 90° (1/4) turn.

• Ensure the cylinder head cover is not tilted.