Timing Chain Guide: Service and Repair

WM 154719 Removing and installing guide and tensioning rails on 4.8-litre DFI engines

Technical values





Preliminary work

1. Remove timing chain. -> 153519 Removing and installing timing chain on 4.8-litre DFI engines - section on "Removing" Service and Repair

Information

Component overview





Timing chain and sprockets









Timing chain and chain guide






Removing guide and tensioning rails

Information

If the timing chain has to be removed or replaced, check the guide and tensioning rails as well as the chain pinions for wear and scoring and replace them if necessary.

Information

- The rolling direction of the timing chain must always be the same.

- If the timing chain is to be reused, the rolling direction of the timing chain must be marked before it is removed.

1. If you have not already done so, remove upper guide rails (guide pad) between the camshafts -6-.





Timing chain and sprockets





2. Detach tensioning rail from the threaded peg. -4-





Timing chain and chain guide





3. Carefully slacken the lower tensioning rail for the oil pump chain. Press the tensioning rail back with a small screwdriver until both staking holes between the tensioning rail and guide rail are aligned. => Oil pump tensioning rail





Oil pump tensioning rail

4. Stake tensioning rail for oil pump chain through the hole in the guide rail using a suitable drill bit, drift punch or nail. This slackens the oil pump chain. => Staking tensioning rail for oil pump chain





Staking tensioning rail for oil pump chain

5. Remove guide rail -3-. Tensioning rail for oil pump chain is locked with -6-.





Guide rail

6. Remove deflector rail -4- by undoing the fastening screws -5-.





Timing chain and sprockets






Installing guide and tensioning rails

1. Fit deflector rail -4- by fitting the fastening screws -5-.





Timing chain and sprockets





2. Fit guide rail -3-. Small tensioning rail is locked with -6- at the guide rail. Slide guide rail onto the threaded pegs and move into the correct installation position with respect to the fitted drive chain for the oil pump. Pull locking pin (this brings the tensioning rail in contact).





Guide rail

3. Slide tensioning rail onto threaded peg. -4-





Timing chain and chain guide





Information

- The rolling direction of the timing chain must always be the same.

- If the timing chain is to be reused, the rolling direction of the timing chain must be marked before it is removed.

4. If you have not already done so, fit upper guide rails (guide pad) between the camshafts -6-.





Timing chain and sprockets






Subsequent work

1. Install timing chain. -> 153519 Removing and installing timing chain on 4.8-litre DFI engines - section on "Installing" Service and Repair
2. Install timing-case cover. -> 153319 Removing and installing timing-case cover on 4.8-litre DFI engines - section on "Installing" Service and Repair
3. Set the timing. -> 150516 Setting camshaft timing on 4.8-litre DFI engines Procedures