Remove/install camshafts

AR05.20-S-6992SD

Remove/install camshafts

06.02.2019

Engine

646 in model 636, 639

1

Belt pulley

3

Retaining pin

5

Markings

2

Intake camshaft

4

Camshaft bearing

6

Timing chain

7

Exhaust camshaft sprocket

8

Camshaft sprocket bolts at exhaust camshaft



Remove

 Caution

Risk of injury caused by scraping or cutting body parts on sharp vehicle parts

Always wear protective gloves when working on or near sharp and non-deburred vehicle parts.
Deburr repair panels.

AS00.00-Z-0017-01A

1

Remove cylinder head cover

AR01.20-S-5014SD

2

Position piston of cylinder 1 to ignition TDC

 Crank engine at crankshaft in direction of engine rotation and position belt pulley (1) as per marking.

 Socket wrench bit

*001589650900

3

Check basic position of camshafts

 Both markings (5) in camshaft sprockets must face each other and the markings of camshaft and camshaft bearing cap must be in alignment (arrows). Piston of cylinder 1 is at ignition TDC.

4

Remove front cover at cylinder head

AR01.30-S-5700SD

5

Mark timing chain (6) relative to exhaust camshaft sprocket (7)

 For work that does not involve the rotation of the crankshaft, secure timing chain (6) with cable tie to exhaust camshaft sprocket (7); remove cable tie after installation.

6

Remove exhaust camshaft sprocket (7) from exhaust camshaft

 Remove camshaft sprocket bolts at exhaust camshaft (8) and remove exhaust camshaft sprocket (7) with mounted timing chain (6).

 Installation: Replace camshaft sprocket bolts at exhaust camshaft (8).

7

Remove camshaft bearing cap

AR05.20-S-6992-04SD

Topical note

Marking on camshaft bearing caps

AH05.20-P-6992-04HE

 Observe camshaft bearing cap marking.

8

Remove intake and exhaust camshafts



Install

9

Insert intake and exhaust camshafts

 Oil the compensating elements and camshaft bearing points, check compensating elements for ease of movement. Align intake and exhaust camshafts at axial bearing. Mount camshafts so that both markings (5) are facing each other.

10

Install camshaft bearing cap

AR05.20-S-6992-04SD

Topical note

Marking on camshaft bearing caps

AH05.20-P-6992-04HE

 Observe camshaft bearing cap marking.

11

Position piston of cylinder 1 to ignition TDC

 Crank engine at crankshaft in direction of engine rotation and position belt pulley (1) as per marking.

 Socket wrench bit

*001589650900

12

Lock intake camshaft (2)

 Slide retaining pin (3) at camshaft bearing (4) into bore in intake camshaft sprocket.

 Retaining pins

*111589031500

13

Check basic position of camshafts

 Both markings (5) in camshaft sprockets must face each other and the markings of camshaft and camshaft bearing cap must be in alignment (arrows). Piston of cylinder 1 is at ignition TDC.

14

Mount exhaust camshaft sprocket (7) at exhaust camshaft

 Mount exhaust camshaft sprocket (7) with mounted timing chain (6) and screw in camshaft sprocket bolts at exhaust camshaft (8).

 Bolt, camshaft sprocket to exhaust camshaft

*BA05.10-N-1001-01F

15

Remove retaining pin (3)

 Retaining pins

*111589031500

16

Install front cover at cylinder head

AR01.30-S-5700SD

17

Crank engine at crankshaft in direction of engine rotation

 At least two revolutions.

 Socket wrench bit

*001589650900

18

Check basic position of camshafts

AR05.20-S-6010SD

If necessary:



Set basic position of camshafts

AR05.20-S-6020SD

19

Install cylinder head cover

AR01.20-S-5014SD



Check

 Warning

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A

20

Check for leak tightness with engine running

 Timing chain, chain tensioner

Number

Designation

Engine 646 in model 636, 639

BA05.10-N-1001-01F

Bolt, camshaft sprocket to exhaust camshaft

Nm

18