Overview - Valvetrain
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NOTE:
Cylinder heads with cracks between valve seats or between valve seat and spark plug thread can still be used without loss of service life if the cracks are minute (max. 0.3 mm (0.0118 in.) width) or only the first four threads of a spark plug thread are cracked.
The cylinder head for cylinder bank 2 (left) is shown.
- Cylinder Head
- Valve guides, checking, refer to VALVE GUIDES, CHECKING .
- Valve Stem Seal
- Removing and installing, refer to VALVE STEM SEALS, REMOVING AND INSTALLING .
- Valve Spring
- For the correct allocation, refer to Fig 4
- Valve Spring Retainer
- Valve Keepers
- Hydraulic Adjusting Element
- Clipped into roller rocker lever -8-
- Mark the installation position with paint for reinstallation
- Lubricate the running surfaces before installing
- Clip
- Not available individually
- Make sure it is secure
- Roller Rocker Lever
- Mark the installation position with paint for reinstallation
- Check roller for easy movement
- Lubricate the running surfaces before installing
- Allocation to the cylinders, refer to Fig 3
- Clip to the hydraulic adjusting element -7- with the clip -6-.
- Exhaust Camshaft
- Removing and installing, refer to CAMSHAFT, REMOVING AND INSTALLING .
- Axial Play, Measuring, refer to CAMSHAFT, MEASURING AXIAL CLEARANCE .
- Radial play, measuring, refer to CAMSHAFT, MEASURING RADIAL CLEARANCE .
- Maximum run out: 0.04 mm (0.0157 in.)
- Camshaft Housing
- With integrated camshaft bearings
- Bolt
- Replacing
- Use old bolts to measure radial play.
- Tightening sequence, refer to Fig 5
- O-Ring
- Replacing
- Bolt
- 5 Nm
- Intake/Exhaust Camshaft Adjusters -F452- through -F479-
- Removing and installing, refer to CAMSHAFT ADJUSTER, REMOVING AND INSTALLING .
- bring into the installed position, refer to Fig 2
- O-Ring
- Replacing
- Plug
- turn to the left to remove with a screwdriver
- O-Ring
- Replacing
- Camshaft Position Sensor 4 -G301-
- Cylinder bank 1 (right) Camshaft Position Sensor 2 -G163-
- Removing and installing, refer to CAMSHAFT POSITION SENSOR -G40-, REMOVING AND INSTALLING, CYLINDER BANK 1 (RIGHT) .
- Bolt
- Tightening specification, refer to OVERVIEW - IGNITION SYSTEM .
- Bolt
- 5 Nm
- Exhaust Camshaft Adjustment Valve 2 -N318-
- Cylinder bank 1 (right) Exhaust Camshaft Control Valve 1 -N318-
- Removing and installing, refer to CAMSHAFT ADJUSTER VALVES, REMOVING AND INSTALLING .
- O-Ring
- Replacing
- Bolt
- 5 Nm
- Camshaft Adjustment Valve 2 -N208-
- Cylinder bank 1 (right) Camshaft Adjustment Valve 1 -N205-
- Removing and installing, refer to CAMSHAFT ADJUSTER VALVES, REMOVING AND INSTALLING .
- O-Ring
- Replacing
- Bolt
- Tightening specification, refer to OVERVIEW - IGNITION SYSTEM .
- Camshaft Position Sensor 3 -G300-
- Cylinder bank 1 (right) Camshaft Position Sensor -G40-
- Removing and installing, refer to CAMSHAFT POSITION SENSOR 2/4 -G163- / -G301-, REMOVING AND INSTALLING, CYLINDER BANK 2 (LEFT) .
- O-Ring
- Replacing
- Flat Ring
- for camshaft adjuster
- Replacing
- Intake Camshaft
- Removing and installing, refer to CAMSHAFT, REMOVING AND INSTALLING .
- Axial Play, Measuring, refer to CAMSHAFT, MEASURING AXIAL CLEARANCE .
- Radial play, measuring, refer to CAMSHAFT, MEASURING RADIAL CLEARANCE .
- Maximum run out: 0.04 mm
- Exhaust Valve
- Do not rework, only grinding is permitted
- Mark the installed position for installation later
- Valve dimensions, refer to VALVE DIMENSIONS .
- Valve guides, checking, refer to VALVE GUIDES, CHECKING .
- Intake Valve
- Do not rework, only grinding is permitted
- Mark the installed position for installation later
- Valve dimensions, refer to VALVE DIMENSIONS .
- Valve guides, checking, refer to VALVE GUIDES, CHECKING .
CAUTION:
The engine could be damaged.
- Bring all of the pins for all of the cam adjustment actuators into the installed position.
-- Press the camshaft adjustment actuator pins down by hand -arrow-.
- The actuator pins must not be in the outward position.
CAUTION:
The engine could be damaged.
- Pay attention to the allocation of the roller rocker lever to the cylinders.
- Roller rocker lever with wide rollers -arrow 1- belong to the cylinders without cylinder cut-off.
- Roller rocker lever with narrow rollers -arrow 2- belong to the cylinders with cylinder cut-off.
- Short Version for Intake Valve
- Long Version for Exhaust Valve
- The tight spring coils -arrows- face toward the cylinder head.
NOTE:
Replace any bolts that were tightened with an additional turn.
-- Tighten the bolts in steps in the sequence shown:
| Step | Bolts | Tightening specification/additional turn |
|---|---|---|
| 1. | -1 to 22- | Install all the way in by hand.
|
| 2. | -1 to 22- | 8 Nm |
| 3. | -1 to 22- | Tighten an additional 90° |