Valvetrain Overview
Valvetrain Overview
Risk of damaging valves and piston heads after working on valvetrain.
• The motor must not be started for about 30 minutes after installing camshafts because the hydraulic equalization elements must seat themselves.
• To ensure valves do not strike 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 max. 0.3 mm, or only the first 4 threads of the spark plug threads are cracked.
• The illustration shows the cylinder bank 2 cylinder head (left).
1 Sealing Plug
• Install with sealant.
2 Cylinder Head
• Check valve guides, 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 => [ 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 - 5 - with securing clip - 9 -
9 Securing Clip
• Not available individually
• Check for secure seating
10 Intake Camshaft
• Removing and installing, refer to => [ Camshafts ] Service and Repair
• Measuring axial play, refer to => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play
• Radial clearance, measuring, refer to => [ Camshaft, Measuring Radial Play ] Camshaft, Measuring Radial Play
• Maximum run out: 0.04 mm
11 Bolt
• Replace
12 Bearing Bracket
• 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 => [ Camshaft, Measuring Axial Play ] Camshaft, Measuring Axial Play
• Radial clearance, measuring, refer to => [ Camshaft, Measuring Radial Play ] Camshaft, Measuring Radial Play
• Maximum run out: 0.04 mm
16 Oil Strainer
17 Intake Valve
• Do not reface, only lapping is permitted
• Mark the installed position for installation later
• Checking, refer to => [ Valves, Checking ] Testing and Inspection
• Valve dimensions, refer to => [ Valve Dimensions ] Specifications
• Check valve guides, refer to => [ Valve Guides, Checking ] Testing and Inspection
18 Exhaust Valve
• Do not reface, only lapping is permitted
• Mark the installed position for installation later
• Checking, refer to => [ Valves, Checking ] Testing and Inspection
• Valve dimensions, refer to => [ Valve Dimensions ] Specifications
• Check valve guides, refer to => [ Valve Guides, Checking ] Testing and Inspection
Installed Position of 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 which have been tightened to an additional torque.
- Tighten the bolts in 3 steps according to the tightening sequence:
