VALVETRAIN Overview
WARNING: This page is about a different car, the 2010 Audi Q7, 2009 Audi Q7, 2008 Audi Q7, and 2007 Audi Q7. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
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.
CAUTION:
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.
NOTE:
Cylinder head for cylinder bank 2 (left) is shown in illustration.
- Sealing Plug
- Valve Stem Seal
- Replacing with the cylinder head installed, refer to VALVE STEM SEALS, CYLINDER HEAD INSTALLED
- replacing with the cylinder head removed, refer to VALVE STEM SEALS, WITH CYLINDER HEAD REMOVED
- Valve Spring
- Installed location Fig 3
- Hydraulic Adjusting Element
- Clipped into roller rocker lever -item 8-
- Checking, refer to HYDRAULIC ADJUSTING ELEMENTS, CHECKING
- Do not interchange
- Lubricate contact surface
- Valve Spring Plate
- Valve Keys
- Securing Clip
- Check for secure seat
- Roller Rocker Lever
- Do not interchange
- Check roller for easy movement
- Lubricate contact surface
- To assemble, clip onto the hydraulic adjusting element -item 4- using a circlip -item 7-.
- Intay
- Removal and installation, refer to CAMSHAFTS
- Checking axial play, refer to CAMSHAFTS, CHECKING AXIAL CLEARANCE
- Check radial clearance using Plastigage (roller rocker lever removed)
- Radial clearance at bearing-dia. 24 mm: 0.024 to 0.066 mm
- Radial clearance at bearing-dia. 36 mm: 0.032 to 0.078 mm
- Run-out: max. 0.04 mm
- Gasket
- Replace
- Bearing bracket
- With integrated camshaft bearings
- Removal and installation, refer to CAMSHAFTS
- Bolt
- Tightening order, refer to Fig 2
- Camshaft Position (CMP) Sensor 2 -G163-
- Bolt
- 9 Nm
- O-ring
- Replace
- Bolt
- 9 Nm
- CMP Sensor 4 -G301-
- O-ring
- Replace
- Compression Ring
- for camshaft adjuster
- Exhaust Camshaft
- Removal and installation, refer to CAMSHAFTS
- Checking axial play, refer to CAMSHAFTS, CHECKING AXIAL CLEARANCE
- Check radial clearance using Plastigage (roller rocker lever removed)
- Radial clearance at bearing-ø 24 mm: 0.024 to 0.066 mm
- Radial clearance at bearing-ø 36 mm: 0.032 to 0.078 mm
- Run-out: max. 0.04 mm
- Cylinder Head
- Check valve guides, refer to VALVE GUIDES, CHECKING
- Intake Valve
- Do not rework, only grinding is permitted
- Mark installed position for re-installation
- Valve dimensions, refer to VALVE DIMENSIONS
- Check valve guides, refer to VALVE GUIDES, CHECKING
- Exhaust Valve
- Do not rework, only grinding is permitted
- Mark installed position for re-installation
- Valve dimensions, refer to VALVE DIMENSIONS
- Check valve guides, refer to VALVE GUIDES, CHECKING
-- Tighten bolts in 2 stages in -1 to 24- sequence as follows.
-- Install bolts by hand as far as stop.
-- Tighten the bolts to 8 Nm.
- The tight spring coils -arrow- face toward cylinder head.