Timing Chain: Service and Repair

Removal
Removal and fitting are described separately.
Remove gear-case cover, top, refer to Timing Cover, Service and Repair.
Removing spark plugs, refer to Powertrain Management
Loosen the central bolt on the vibration damper, refer to Harmonic Balancer.





Rotate engine on loosened central screw enginewise until the first cylinder reaches its TDC firing position.





Note: The alignment bores of the camshafts in the firing TDC position point upwards.





Remove dust cover from locating bore.





Secure crankshaft in TDC position with Special Tool 11 2 300.





Position camshaft with Special Tool 11 3 240 in firing TDC position of first cylinder.

Note: Crankshaft and camshafts remain locked until assembly is complete.

Remove the loosened central bolt and take out the vibration damper.
Removing gear case cover, bottom, refer to Timing Cover, Service and Repair.
Remove the hydraulic chain tensioner, refer to Timing Chain Tensioner, Service and Repair.





Remove the chain wheels.





Remove timing chain sprocket with timing chain from camshaft.





If necessary, replace the slide and tensioning rails.
Release the slide and tensioning rails.

Installation
Fitting and removal are described separately.





Install the slide and tensioning rails.
Turn the adjusting screw of the slide rail back approx. two revolutions.





Fasten the slide rail to the cylinder head using screw (1).
Insert the screws and tighten them all except screw (1).
Remove screw (1).





Place the adjusting screw of the slide rail free of play on the cylinder head.





Insert the screw (1) and tighten down the slide rail.





Check the chain wheel and replace if necessary.
Align sprocket with woodruff key and install sprocket with timing chain in position.





Check the chain wheels and replace if necessary.
Place the chain with the chain wheels.

Note:
The arrows on the chain wheels in cylinder axis point up.
Align long bores centrally.





Place the sensor gear onto the inlet chain wheel.

Note: Arrow on sensor gear in cylinder axis points up.





Insert all chain wheel screws and tighten so that they are free of play; the chain wheels remain loose.

Install hydraulic chain tensioner.

Caution: Note installation instructions, refer to Timing Chain Tensioner, Service and Repair.





Tighten down the chain wheels.
Tightening torque, refer to Engine, Specifications.
Remove Special Tools 11 2 300 and 11 3 240.
If necessary, check the control diagram, found in Checking Camshaft Timing, refer to Camshaft, Lifters and Push Rods
Assemble engine.