Timing Drive — General Information, Component Maintenance (Mercedes-Benz S-Class W140)

Contents: General information ↡ Servicing Timing Drive Components ↡

Note: The camshafts can be turned without the risk of valve-piston collision when the crankshaft is set to the position 45° before TDC of the piston of the first cylinder.

Note: The timing chain can be replaced without disassembling the engine. Using the tools listed below, the new chain can be connected to the old one, threaded around the sprockets and calked (see section Timing chain replacement).

Attention! If assembled incorrectly, the valves may collide with the piston crowns!

General information

To perform the procedures for removing and installing timing drive components, you will need the following special tools:

Camshaft lock pin x4 - No.111589031500;
Camshaft Key - No.119589000100;
Crankshaft Hub/Pulley Puller - #103589003300;
Flywheel/Drive Disc Locking Tool - #116589014000;
Timing Chain Link Installation Tool - No.000589584300;
Set of stamp holders for installing timing chain links - No.103589016300;
Timing chain releases - No.110589035900;
Pulley Locking Tool - No.603589004000.

Please note the following points:

Unless otherwise stated, rotate the engine in the normal direction only;
Observe the specified tightening forces for fasteners;
If equipped, do not forget to mark the installation position of the CKP sensor before removal;
Do not turn the crankshaft by the camshaft sprockets or other timing drive sprockets;
Do not turn the crankshaft or camshafts with the timing chain removed.

Servicing Timing Drive Components

Timing drive design
1 - Crankshaft sprocket; 2 - Bearing finger; 3 - Tensioner guide; 4 - Chain tensioner; 5 - Exhaust camshaft sprocket; 6 - Upper chain guide; 7 - Intake camshaft sprocket; 8 - Right cylinder head chain guide; a = 8.1 mm; b = 9 mm; 9 - Guide pin; 10 - Guide pin; 11 - Intermediate sprocket; 12 - Guide pin; 13 - Guide pin; 14 - Inner guide of the chain of the left cylinder head; a = 8.1 mm; b = 9 mm; 15 - Intake camshaft sprocket; 16 - Upper side chain guide; 17 - Exhaust camshaft sprocket; 25 - Timing chain (216 double links); 26 - Left cylinder head outer chain guide; a = 8.1 mm; b = 9 mm; 27 - Guide pin; 28 - Guide pin; 29 - Cylinder block chain guide; a = 8.1 mm; b = 9 mm; 30 - Bolted bearing pin; 31 - Bolted bearing finger

Timing drive components installation details
1 - Timing marks for bringing the engine to the TDC position of the end of the compression stroke of the first cylinder; 2 - Rods with a diameter of 6.5 mm for fixing camshafts; 3 - When installing the chain, ensure that the camshaft adjuster tabs (3) are in the "retard" position.; 4 - The camshaft can be locked from turning using a key.; 5 - Removing the chain tensioner assembly

1. Disconnect the negative cable from the battery.

2. To make it easier to turn the engine, remove all spark plugs.

3. Bring the crankshaft to a position 45° before TDC of the piston of the first cylinder.

4. Insert the locking rods (2) with a diameter of 6.5 mm into the camshafts.

5. When installing the chain, ensure that the inlet camshaft adjuster tabs (3) are in the "retard" position.

Attention! If assembled incorrectly, the valves may collide with the piston crowns!

Before performing repair procedures, remove the tensioner assembly - do not tilt the assembly during removal.

Note: The right cylinder head exhaust camshaft must be locked with a locking rod before removing the tensioner.

1. The camshaft can be locked from turning using the key (4).

2. After completing the necessary repairs, install the tensioner back in place.

3. Tighten the NEW intake camshaft adjuster and exhaust camshaft sprocket bolts to 18 Nm (type A bolt with separate washer) or 20 Nm + 60° (type B bolt with built-in washer).

Note: During repair work, the Type A bolt should be replaced with a disposable Type B bolt.

4. On engine 119.97, replace the governor spring if its dimensions do not meet the requirements Specifications.

5. Tighten the NEW intake camshaft adjuster bolt to 7 Nm (type A bolt with separate washer) or 5 Nm + 90° (type B bolt with built-in washer).