Valvetrain Overview
Valvetrain Overview
Risk of damaging valves and piston heads after working on the valvetrain.
• The motor must not be started for about 30 minutes after installing the camshafts because the hydraulic equalization elements must seat themselves.
• To ensure the valves do not strike the pistons when starting, carefully rotate engine at least 2 full revolutions.
• 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 width of maximum 0.3 mm, or only the first 4 threads of the spark plug threads are cracked.
• The cylinder head for cylinder bank 2 (left) is shown in the illustration.
1 Sealing Plug
• Install with sealant; sealant, refer to the Parts Catalog
2 Cylinder Head
• Valve guides, checking, refer to => [ Valve Guides, Checking ] Testing and Inspection
3 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, refer to => [ Valve Stem Seals with Cylinder Head Removed ] Valve Stem Seals With Cylinder Head Removed
4 Valve Spring
5 Hydraulic Adjusting Elements
• Clipped into roller rocker lever - 8 -
• Checking, refer to => [ Hydraulic Adjusting Elements, Checking ] Testing and Inspection
• Mark the installed position for installation later
• Lubricate the running surfaces before installing
6 Valve Spring Plate
7 Valve Retainers
8 Roller Rocker Lever
• Mark the installed position for installation later
• Check roller for easy movement
• Lubricate the running surfaces before installing
• To assemble, clip onto the hydraulic adjusting element - 9 - with securing clip - 5 -
9 Clip
• Not available individually
• Make sure it is secure
10 Intake Camshaft
• Removing and installing, refer to => [ Camshafts ] Service and Repair
• Measuring axial play, refer to => [ Camshafts, Checking Axial Clearance ] Camshafts, Checking Axial Clearance
• Radial clearance, measuring, refer to => [ Camshaft, Measuring Radial Clearance ] Camshaft, Measuring Radial Clearance
• Maximum run out: 0.04 mm
11 Bolt
• Replace
12 Guide Frame
• With integrated camshaft bearings
• Removing and installing, refer to => [ Camshafts ] Service and Repair
13 Compression Ring
14 Compression Ring
15 Exhaust Camshaft
• Removing and installing, refer to => [ Camshafts ] Service and Repair
• Measuring axial play, refer to => [ Camshafts, Checking Axial Clearance ] Camshafts, Checking Axial Clearance
• Radial clearance, measuring, refer to => [ Camshaft, Measuring Radial Clearance ] Camshaft, Measuring Radial Clearance
• Maximum run out: 0.04 mm
16 Oil Strainer
17 Intake Valve
• Do not rework, only lapping is permitted
• Mark the installed position for installation later
• Checking, refer to => [ Valves, Checking ] Testing and Inspection
• For the correct valve dimensions, refer to => [ Valve Dimensions ] Specifications
• Valve guides, checking, refer to => [ Valve Guides, Checking ] Testing and Inspection
18 Exhaust Valve
• Do not rework, only lapping is permitted
• Mark the installed position for installation later
• Checking, refer to => [ Valves, Checking ] Testing and Inspection
• For the correct valve dimensions, refer to => [ Valve Dimensions ] Specifications
• Valve guides, checking, refer to => [ Valve Guides, Checking ] Testing and Inspection
Installed Position, Valve Spring
• The tight spring coils - arrow - face toward the cylinder head.
Camshaft Guide Frame Tightening Specifications and Sequence
• The guide frame for the left cylinder head camshaft is shown in the illustration. The right cylinder head is identical.
• Replace bolts that are tightened to the specification.
- Tighten the bolts in 3 steps in the sequence shown:
