Camshaft Timing Chain
Camshaft Timing Chain
CAUTION!
Crankshaft and camshafts may only be turned over with engine completely installed and may only be turned at the crankshaft. The timing chain covers and the chain tensioner for the right camshafts timing chain must be installed.
• The camshaft bar (T10068) serves exclusively to lock the camshaft at TDC. To counter-hold, an open-end wrench 32 mm must be set on the hex of the camshaft.
Special tools, testers and auxiliary items required
• Locking pin (3242)
• Camshaft bar (T10068)
• Drill bit 3.5 mm dia.
Removing
• Engine removed.
• Engine separated from transmission.
- Remove drive plate => [ Drive Plate ] Drive Plate.
- Remove upper section of intake manifold => [ Intake Manifold Upper Section ] Cylinder Head, Valvetrain.
- Remove intake manifold lower part => [ Intake Manifold Lower-Section ] Intake Manifold Lower-Section.
- Remove cylinder head covers => [ Cylinder Head Cover ] Service and Repair.
- Rotate crankshaft at center bolt in direction of engine rotation to TDC of ignition timing.
• The marking - 2 - on the vibration damper must align with the housing separation point - 1 -.
• At the same time, the camshaft bar (T10068) must engage in both shaft grooves.
- If necessary, turn crankshaft 1 rotation further.
• If necessary, turn camshafts back and forth slightly using 32 mm open-end wrench. Camshaft bar (T10068) must not be installed during this process.
- Remove sealing plug from left side of cylinder block.
- Screw crankshaft holder (3242) into the hole (20 Nm).
- Remove all covers for timing chains => [ Timing Chain Covers ] Timing Chain Covers.
- If reusing the current timing chains, mark the direction of rotation and allocation of both the left and right chains with a paint marker.
CAUTION!
Both camshaft timing chains must always be removed and installed together, otherwise the installation markings will not be able to be positioned properly.
- Push chain tensioner for camshaft timing chain on cylinder bank 2 (left) downward and lock in position with drill bit 3.5 mm dia. - 1 -.
- Remove bolts - 6 - and chain tensioner - 5 -.
- Remove bolt - 3 - and guide piece - 2 -.
- Pull tensioning rail - 4 - from mounting pin.
- Pull guide rail - 1 - from mounting pins.
- Remove mounting pins - 1 -.
- Remove timing chain for cylinder bank 2 (left), beginning at the intake camshaft adjuster - 2 -.
• To ease the removal of the timing chain, rotate the camshaft adjuster back and forth slightly.
- Pull tensioning rail - 1 - and guide rail - 2 - for cylinder bank 1 (right) from mounting pins.
• To ease the removal of the guide rail, rotate the intake camshaft slightly to the left at hex, thereby paying attention to the camshaft bar.
- Remove mounting pin - 1 -.
- Remove timing chain for cylinder bank 1 (right), beginning at the intake camshaft adjuster - 2 -.
• To ease the removal of the timing chain, rotate the camshaft adjuster back and forth slightly.
Installing
• Secure camshaft in TDC position using camshaft bar (T10068).
• Secure crankshaft in TDC position using crankshaft holder (3242).
• Drive chain installed => [ Installing ] Drive Chain.
- Place camshaft timing chain for cylinder bank 1 (right) onto the chain sprocket for camshaft drive and onto the camshaft adjuster.
• The copper-colored chain links face toward the transmission.
• The copper-colored chain links must be positioned to the chain sprockets as shown in the illustration.
• The exact positions are shown in the following illustrations.
Chain sprocket for camshaft drive
• The copper-colored chain link - 1 - must be positioned centrally to the threaded hole - 3 - when the camshaft timing chain - 2 - is tensioned.
• The copper-colored chain link that is located behind on the drive chain is only positioned as shown the first time it is laid in place. If the drive chain was not removed, the placement of the chain link is of no significance.
Camshaft adjuster for exhaust camshaft
• The copper-colored chain link - arrow - must align with marking - 1 - on exhaust camshaft adjuster.
Camshaft adjuster for intake camshaft
• The copper-colored chain link - arrow - must align with marking - 1 - on intake camshaft adjuster.
- Push guide rail - 2 - onto mounting pins.
- Install mounting pin using locking compound; Locking compound.
- Install tensioning rail - 1 -.
• If the guide rail can not be pressed on, rotate the intake camshaft slightly to the left, thereby paying attention to the camshaft bar.
- Place the camshaft timing chain for cylinder bank 2 (left) onto the chain sprocket for camshaft drive and onto the camshaft adjuster.
• The copper-colored chain links face in direction of engine.
• The copper-colored chain links must be positioned to the chain sprockets as shown in the illustration.
• The exact positions are shown in the following illustrations.
- Install guide rail - 1 - before checking the position of the chain.
Chain sprocket for camshaft drive
• The copper-colored chain link - 1 - must be positioned centrally to the threaded hole - 3 - when the camshaft timing chain - 2 - is tensioned.
• In the illustration, the copper-colored chain link - 4 - faces toward the viewer for improved clarity. When installed correctly, it faces in direction of the engine.
Verification:
• The copper-colored chain links - 1 - and - 4 - of the camshaft timing chain for the left and right cylinder banks must be positioned directly behind one another and be centrally aligned to the threaded hole - 3 - when installed properly.
Camshaft adjuster for exhaust camshaft
• The copper-colored chain link - arrow - must align with marking - 1 - on exhaust camshaft adjuster.
Camshaft adjuster for intake camshaft
• The copper-colored chain link - arrow - must align with marking - 1 - on intake camshaft adjuster.
- Install mounting pins and tensioning rail - 4 -.
- Fasten guide piece - 2 - with bolt - 3 -.
- Fasten chain tensioner - 5 - with bolts - 6 -.
- Pull drill bit 3.5 mm dia. - 1 - out of alignment hole, thereby releasing the chain tensioner.
• Before continuing the assembly, verify the correct positioning of the chain links to the markings.
- Install covers for timing chains => [ Timing Chain Covers ] Timing Chain Covers.
- Remove crankshaft holder (3242).
- Turn crankshaft 2 rotations in engine direction of rotation, until the marking - 2 - on the vibration damper is aligned with the housing separation point - 1 -.
- Screw crankshaft holder (3242) into hole (20 Nm).
• On top of camshafts, the camshaft bar (T10068) must engage in both shaft grooves.
- If necessary, turn camshafts back and forth slightly using 32 mm open-end wrench. Camshaft bar (T10068) must not be installed during this process.
- Remove camshaft bars (T10068).
- Remove crankshaft holder (3242).
- Screw sealing plug of TDC marking with new seal into the guide frame.
The rest of the installation is in reverse order of removal, note the following:
- Install cylinder head covers => [ Installing ] Service and Repair.
- Install intake manifold lower-section => [ Intake Manifold Lower-Section ] Intake Manifold Lower-Section.
- Install intake manifold upper-section => [ Intake Manifold Upper Section ] Cylinder Head, Valvetrain.
- Install drive plate => [ Drive Plate ] Drive Plate.
Tightening Specifications
* Insert using locking compound; locking compound.