Timing Chain Guide: Service and Repair

Replacing guide and tensioning rails








Tools and materials

Replacing guide and tensioning rails

Caution: Never twist the crankshaft against the direction of movement!
Proceed carefully while working as otherwise the engine can become damaged!
Only turn the engine on the crankshaft and never on the camshaft as the timing chain can jump over!
When working on the engine, absolute cleanliness is essential! Even the smallest particles of dirt can block up oil bores!
Please observe general warning rates arid working regulations!

Note:
^ The running direction of the timing chain must always be the same.
^ If the timing chain is to be reused, the running direction of the timing chain must be marked before it is removed!

1. Remove engine.
2. Remove cover for camshaft housing.
3. Remove chain case.





4. Loosen the fastening screws of the camshaft wheels and camshaft adjusters (1 or 2 turns). To do this, counter the hexagon a/f 32 of the wheels with ring wrench. Loosen pan-head screw M12 by 1 or2 turns with socket wrench insert T60.
5. Pull guide rails between the camshafts away from the threaded pegs. To do this, let timing chain dangle between the camshafts.

Figure shows guide rail with fitted chain case lid and timing chain.





Note: If the timing chain is to be reused, the running direction of the timing chain must be marked before it is removed.

6. Mark running direction of timing chain. Remove timing chain off all chain sprockets, pulling it forwards.





7. Pull guide rail -3- and tensioning rail -5- off threaded pegs. Ensure that the spring of the tensioning rail for the oil pump drive is in the correct position in relation to the guide rail -3- .





8. Remove guide rail -3- by loosening 4 fastening screws M8 x 35.





9. Remove plastic lid of oil pump drive -7-. To do this, unscrew 2 combination screws M5 x 20 -8- and remove plastic lid. Remove guide rail -9- and tensioning rail -6-.

Installing guide and tensioning rails





1. Insert guide rail -9- and tensioning rail -6-. Install plastic lid of oil pump drive -7- . To do this, insert plastic lid and screw down 2 combination screws M5 x 20 -8- to 5, 6 Nm (4 ft. lbs.).





2. Place guide rail -3- and tensioning rail -5- on threaded pegs. Position the spring of the tensioning rail for oil pump drive correctly on guide rail -3-.
3. Install timing chain.
4. Place guide rails between the camshafts onto the threaded pegs. To do this, let timing chain dangle between the camshafts.





Figure shows guide rail with installed chain case lid.

5. Install chain case lid.
6. Set the timing.








7. Tighten all camshaft wheels with the M12 pan-head screw again. To do this, counter the hexagon (a/f 32) of the corresponding camshaft wheel with a ring wrench and tighten the M12 pan-head screw with the T60 socket insert wrench.
8. Install cover for camshaft housing.
9. Install engine.





Tightening torques