Removal and installation of timing components (Mercedes-Benz M-Class W163)

The details of the camshaft installation on the 612 series engines are shown in the illustrations to which all references in the text refer.

Removal

1. Remove the cylinder head cover trim panels.

2. Remove the injectors (Y76).

3. Remove the cylinder head cover (12).



4. Turning the crankshaft in the normal direction, bring the engine to the TDC position of the piston of the first cylinder - the marks on the camshaft bodies and bearing caps should align (arrows).

5. Lock the intake camshaft (2) by inserting the special rod (3) through the bearing cap and into the hole (A) of the drive gear (5).

6. Remove the chain tensioner (10) (see Section Removal and installation of timing drive components).

7. Remove the front cylinder head cover (see Section Removal and installation timing belt covers).

8. Remove the upper chain guide (see Section Removal and installation of timing drive components).

9. Mark the position of the chain on the camshaft drive sprocket (6).

10. Unbolt the sprocket (6) and remove it from the exhaust camshaft journal (1).

11. After marking, remove the camshaft bearing caps (8).

12. Carefully remove the camshafts (1 and 2) from the cylinder head.

Installation

1. Install the camshafts in their standard places in the cylinder head, - ensure that the requirements of the basic installation are met (see Section Setting the base position of the camshafts).

2. Bring the engine to a position 30° before TDC of the piston of the first cylinder.

3. Referring to the markings applied during dismantling, install the bearing caps (8) in place.

4. Lock the intake camshaft (2) with the rod (3).

5. Place the drive sprocket (6) on the exhaust camshaft journal (1).

6. Install the chain tensioner (10).

7. Make sure that the basic camshaft installation requirements are met (see Section Setting the base position of the camshafts).



8. Install the cylinder head cover (12).

9. Clean and install the injectors (Y76) (see Chapter Removal and installation of fuel distribution line and injectors).

10. Install the cylinder head cover trim panels.

11. Start the engine and check for signs of developing leaks.

12. Finally, clear the memory of the on-board diagnostic module (see Chapter Engine electrical systems).

Camshaft end caps

1. The installation details of the camshaft end covers are shown in the illustration to which all references in the text refer.

2. Remove the camshafts (1 and 2) (see above).

3. Using a suitable screwdriver, remove the cover (3) from the end portion of the rear camshaft journal - try not to damage the walls of the seat.

4. Clean and degrease the socket for installing the cover.

5. Using a suitable drift, seat the new end cover into the shaft journal to the required depth.

Caution! If the cover is installed too deeply, it may block the oil supply!

6. Install the camshafts into the cylinder head (see above).

M628

Camshafts

The camshaft installation details on the 628 series engines are shown in the illustrations to which all references in the text refer.

Removal

1. Disconnect the air distributor.

2. Disconnect the boost air intake hose from the cylinder head and turbocharger and push it aside.

3. Remove the injector cover.

4. Remove the injectors (Y76).

5. Remove the cover (2) of the corresponding cylinder head.



6. Remove the bypass hose of the air boost tract.

7. Remove the vacuum pump (4).

8. Turn the crankshaft in the normal direction, bring the engine to the TDC position of the piston of the first cylinder - the marks on the bodies of the camshafts and their covers should align.

9. Lock the intake camshaft (6) by inserting the rod (7) through the first bearing cap and into the hole (A) in the drive gear (8).

10. When working on the right head, using the window in the front cover, place the holder on the camshaft drive sprocket (10). On the left head, a special holder is mounted on the cylinder head, placed on the drive sprocket (10) and secured with the cylinder head cover bolts (14).

11. Separate the drive sprocket (10) from the exhaust camshaft journal (12).

12. Remove the caps (13) of the camshaft bearings (6 and 12) and remove the latter from the cylinder head, leaving the sprocket fixed in the holder.

Installation

1. Place the camshafts in their proper places in the cylinder head, - ensure that the basic installation requirements are met (see Section Setting the base position of the camshafts).

2. Align the camshafts on the thrust bearings (arrow).

3. Using the rod (7), lock the intake camshaft (6).

4. Attach the sprocket (10) to the exhaust shaft journal (12).

5. Make sure that the basic installation requirements are met (see Section Removal and installation of timing drive components).

6. Further installation is carried out in the reverse order of dismantling the components.

7. Start the engine and check for signs of developing leaks.



8. Finally, clear the memory of the on-board diagnostic module (see Chapter Engine electrical systems).

Camshaft end caps

1. The installation details of the camshaft end caps are shown in the accompanying illustration, to which all references in the text refer.

2. Remove the camshafts (1 and 2) (see above).

3. Using a suitable screwdriver, remove the cover (3) from the end portion of the rear camshaft journal - try not to damage the walls of the seat.

4. Clean and degrease the socket for installing the cover.

5. Using a suitable drift, seat the new end cover into the shaft journal to the required depth.

Caution! If the cover is installed too deeply, it may block the oil supply!

6. Install the camshafts into the cylinder head (see above).

Camshaft bed

1. The installation details of the camshaft bed of the 628 series engine are shown in the illustrations to which all references in the text refer.

2. Remove the air distributor.

3. Remove the camshafts (3a and 3b) (see above).

4. Secure the valve tappets (5) equipped with hydraulic compensators in their mounting sockets.

Note: Alternatively, the tappets can be removed from the shaft bed, but a magnet should not be used for this purpose - magnetizing the tappets can result in metal filings accumulating on them!

5. Remove the camshaft bed (10).

6. Installation is carried out in reverse order.

7. Start the engine and check for signs of developing leaks.

8. Finally, clear the memory of the on-board diagnostic module (see Chapter Engine electrical systems).