Camshaft, Lifters and Push Rods: Service and Repair

Valvetrain Overview

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

• After installing the camshafts, the engine may not be started for approximately 30 minutes. The hydraulic lash adjusters must seat themselves (otherwise the valves will crash into the pistons).

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

• Always replace gaskets and seals.






1 Exhaust Valve

• Do not rework, only lapping is permitted.

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

• Checking 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

5 Valve Spring

6 Valve Spring Plate

7 Valve Retainers

8 Roller Rocker Arm with Hydraulic Lash Adjuster

• Do not interchange.

• Lubricate the contact surfaces.

9 Exhaust Camshaft

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

• Radial play on bearing diameter - 24 mm: 0.024 to 0.066 mm.

• Radial play on bearing diameter - 32 mm: 0.030 to 0.051 mm.

• Run-out: Max. 0.04 mm.

10 Cylinder Head Cover

• With integrated camshaft bearings.

• Clean the sealing surface, reworking is not permitted.

• Remove the old sealant residue.

11 Bolt

• Always replace.

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

12 O-ring

• Always replace.

• Lubricate with engine oil.

13 Sealing Plug

14 Intake Camshaft

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

• Radial play on bearing diameter - 24 mm: 0.024 to 0.066 mm.

• Run-out: Max. 0.04 mm.

15 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 (3334).

16 Intake Valve

• Do not rework, only lapping is permitted.

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

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

Cylinder Head Cover Bolt Tightening Sequence





- Replace the bolts.

- Hand tighten the bolts in several passes in sequence - 1 through 6 -.

- Tighten the bolts in sequence - 1 through 6 - to 8 Nm using a torque wrench.

- Tighten the bolts an additional 90° (1/4) turn using a ratchet in sequence - 1 through 6 -.

• Ensure the cylinder head cover is not tilted.

Valve Dimensions





• Intake and exhaust valves must not be refaced by grinding. Only lapping is permitted.