150719 Removing and Installing Camshaft Timing Gear (Sprocket) on 4.8-Litre DFI Engines
WM 150719 Removing and installing camshaft timing gear (sprocket) on 4.8-litre DFI engines
Information
Component changes for model year 2009 as of October 2008
Information
Always read the information concerning modified tightening specifications and component changes relating to repairs provided for specific engine numbers in the Information section => 1001IN IMPORTANT component changes for V8 engines as of October 2008.
Preliminary work
1. Remove cylinder head cover (valve cover) on both cylinder banks. => 158219 Removing and installing cylinder head cover (valve cover) on 4.8-litre DFI engines - section on "Removing"
2. The spark plugs should be removed to make the crankshaft easier to turn. => 287020 Removing and installing spark plugs on DFI engines - section on "Removing"
Removing camshaft timing gear (sprocket)
NOTICE
Incorrect handling of crankshafts
- Risk of damage to the timing system
-> Never turn the crankshaft against the rolling direction or when the chain tensioner is removed.
-> Proceed carefully with your work.
-> Only turn the engine at the crankshaft.
-> Reset the timing after working on the camshaft.
-> Observe general warning notes and working regulations.
1. Turn the crankshaft at the vibration balancer so that the vibration balancer's staking bore -2- is located approx. 45° ° in front of the lower staking point on the timing-case cover -1-.
Staking bore 45 ° before TDC of cylinder 1
2. Remove chain tensioner. => 153619 Removing and installing chain tensioner on 4.8-litre DFI engines - section on "Removing".
3. Loosen all four screws of the camshafts (sprockets and camshaft controllers) (undo one to two turns). Counter at the respective hexagon. => Loosening camshafts (illustrated with timing-case cover removed)
Loosening camshafts (illustrated with timing-case cover removed)
Information
- Move the camshafts carefully. Do not force.
- Turn in the other direction if necessary.
Information
A data matrix coding is shown on the staking dihedron of the camshafts. This is a square black/white dotted marking used for electronic identification purposes during the production process. This marking can be used as an aid when inserting the camshafts into the cylinder head. All four camshafts press against the valves the least when the data matrix coding is facing upwards during installation.
4. Turn all four camshafts so that all the data matrix codings at the adjustment edges point upwards approximately simultaneously (this enables the camshafts to exert the minimum amount of pressure on the valve lifters). The camshafts are turned at their hexagon using an appropriate open-ended wrench => Camshaft position for cylinders 1 to 4 => Camshaft position for cylinders 5 to 8 => Hexagon at camshaft. Observe identical information on assembling the camshafts.
Camshaft position for cylinders 1 to 4
Camshaft position for cylinders 5 to 8
Hexagon at camshaft
5. Loosen timing chain.
6. Remove screw for the respective camshaft timing gear -3- and carefully take out camshaft timing gear -2- with both hands under the timing chain. Loosen the camshaft timing gear using a rubber hammer carefully from behind if necessary.
Timing chain and sprockets
Installing camshaft timing gear (sprocket)
NOTICE
Incorrect handling of crankshafts
- Risk of damage to the timing system
-> Never turn the crankshaft against the rolling direction or when the chain tensioner is removed.
-> Proceed carefully with your work.
-> Only turn the engine at the crankshaft.
-> Reset the timing after working on the camshaft.
-> Observe general warning notes and working regulations.
Timing chain and sprockets
1. Lift timing chain and place camshaft timing gear carefully on the camshaft. In order to have sufficient play in the timing chain, turn the loosened camshaft controller back and forth if necessary. Place timing chain on camshaft timing gear.
2. Fit screw for camshaft timing gear and screw it in loosely.
3. Screw in the four screws of the sprockets and camshaft controller as far as possible (it must still be possible to turn the sprockets and camshaft controller to adjust the timing).
4. Set the timing. => 150516 Setting camshaft timing on 4.8-litre DFI engines. Do not tighten the sprockets and camshaft controller to the final tightening until after the timing has been set.
Subsequent work
1. Fit spark plugs. => 287020 Removing and installing spark plugs on DFI engines - section on "Installing"
2. Fit valve cover. => 158219 Removing and installing cylinder head cover (valve cover) on 4.8-litre DFI engines - section on "Installing"