Camshaft, Lifters and Push Rods: Service and Repair
Valvetrain Overview
• Cylinder heads with cracks between the valve seats, or between the valve seat and the spark plug threads, can continue to be used without reducing the service life, as long as the cracks have a Max. width of 0.3 mm, or only the first 4 threads of the spark plug threads are cracked.
• The cylinder head and guide frame must be replaced together.
• Do not grind the valve seats in the cylinder head. Only hand lapping the valves is permitted.
• Do not start the engine for approximately 30 minutes after installing the camshafts. The hydraulic lash adjuster must seat themselves (otherwise the valves will seat themselves on 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 the valves do not strike the pistons.
• Always replace the gaskets and seals.
1 Bolt
• 8 Nm + 90° (1/4) additional turn.
• Always replace.
2 Guide Frame
• Removing and installing, refer to => [ Camshafts ] Service and Repair.
• With integrated camshaft bearings.
• Clean the sealing surface, reworking is not permitted.
• Remove any old sealant residue.
3 Sprocket
• For the exhaust camshaft.
4 Bolt
• 60 Nm + 90° (1/4) additional turn.
• Always replace.
5 Bolt
• 60 Nm + 90° (1/4) additional turn.
• Always replace.
6 Camshaft Adjuster
• For the intake camshaft.
7 Seals
• For the camshaft adjuster.
• Note the installed position, refer to => [ Camshafts ] Service and Repair.
8 Timing Chain
• Removing from the sprockets, refer to => [ Valve Timing, Adjusting ] Adjustments.
9 Cylinder Head
• Do not grind the valve seats, only hand lapping is permitted.
10 Roller Rocker Arm with Hydraulic Lash Adjuster
• Do not interchange.
• Lubricate the contact surfaces.
11 Valve Retainers
12 Spring Seat
13 Valve Spring
14 Valve Stem Seal
• Removing and installing, refer to => [ Valve Stem Seals ] Service and Repair.
15 Valve Guide
• Checking, refer to => [ Valve Guide, Checking ] Testing and Inspection.
16 Intake Valve
• Do not grind, only hand lapping is permitted.
• For the correct valve dimensions, refer to => [ Valve Dimensions ] [1][2]Specifications.
• Valve guide, checking. Refer to => [ Valve Dimensions ] [1][2]Specifications.
17 Exhaust Valve
• Do not grind, only hand lapping is permitted.
• For the correct valve dimensions, refer to => [ Valve Dimensions ] [1][2]Specifications.
• Valve guide, checking. Refer to => [ Valve Guide, Checking ] Testing and Inspection.
18 Sealing Plugs
• Always replace.
• Installing, refer to => [ Camshafts ] Service and Repair.
19 Intake Camshaft
• Removing and installing, refer to => [ Camshafts ] Service and Repair.
• Check the radial clearance using Plastigage(R) (roller rocker arms are removed).
• Wear limit:
0.1 mm
• Runout:
Max. 0.035 mm
• Axial clearance:
Max. 0.17 mm
20 Exhaust Camshaft
• Removing and installing, refer to => [ Camshafts ] Service and Repair.
• Check the radial clearance using Plastigage(R) (roller rocker arms removed).
• Wear limit:
0.1 mm
• Runout:
Max. 0.035 mm
• Axial clearance:
Max. 0.17 mm