Remove/install camshafts

AR05.20-P-6992CD

Remove/install camshafts

04.09.2019

Engine

651 in model 166, 172, 204, 207, 212, 218, 221

Modification notes

26.08.2019

Note added.

Operation step 7

1

Bolts

4

Camshaft bearing cap

7

Exhaust camshaft

2

Camshaft sprockets

5

Camshaft bearing cap

8

Tip

3

Timing chain

6

Intake camshaft

9

Marking



Remove

 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

1

Remove cylinder head cover.

AR01.20-P-5014CD

2.1

Turn engine at the crankshaft with a counterholder in the direction of engine rotation and place piston of cylinder 1 at top dead center (TDC) (ignition TDC).

Engine 651 in model 166, 172, 204, 207, 212, 218, 221
except code B03 (ECO start/stop function)


Do not crank engine at screw/bolts (1) for camshaft sprockets (2). Do not rotate engine backwards.
The timing chain (3) can skip otherwise and cause engine damage.

 The 0° marking on belt pulley/vibration damper must align with the marking on the crankcase.
The tip (8) must be flush with the marking (9) on the camshaft bearing cap (4 or 5). Turn crankshaft another revolution to 0° if necessary.

 Counterholder

*651589004000

2.2

Turn engine at the crankshaft with a suitable tool in the direction of engine rotation and place piston of cylinder 1 to ignition TDC.

Engine 651 in model 166, 172, 204, 207, 212, 218, 221
with code B03 (ECO start/stop function)


Do not crank engine at screw/bolts (1) for camshaft sprockets (2). Do not rotate engine backwards.
The timing chain (3) can skip otherwise and cause engine damage.

 The 0° marking on belt pulley/vibration damper must align with the marking on the crankcase.
The tip (8) must be flush with the marking (9) on the camshaft bearing cap (4, 5). Turn crankshaft another revolution to 0° if necessary.

3

Remove the chain tensioner.

AR05.10-P-7800CD

4

Mark timing chain (3) relative to the camshaft sprockets (2).

5

Remove screws of the camshaft bearing caps (4, 5) in steps and remove camshaft bearing caps (4, 5).

AR05.20-P-6992-04CD

6

Unhook intake camshaft (6) and exhaust camshaft (7) from the timing chain (3) and remove.

General information on checking camshafts and bearing points of camshafts

AH05.20-P-1000-09SZ


Cover timing case shaft with clean rags.
Engine damage can occur otherwise.

 Secure timing chain (3) against falling down.

7

Remove screws (1) and remove camshaft sprockets (2) from the intake camshaft (6) or exhaust camshaft (7).

When installing new camshaft sprockets (2).

 Observe the left-hand thread!



Install

8

Push camshaft sprockets (2) onto the intake camshaft (6) and exhaust camshaft (7) and tighten screws (1) finger-tight.

If camshaft sprockets (2) or intake camshaft (6) or exhaust camshaft (7) were replaced.

9

Hook intake camshaft (6) and exhaust camshaft (7) into the timing chain (3) and place in the bearing halves of the cylinder head.

 Note the marking on the timing chain (3).
Lubricate roller-type cam follower and camshaft bearing points.
Insert intake camshaft (6) and exhaust camshaft (7) in such a way that the tip (8) is aligned with the marking (9).

10

Install camshaft bearing caps (4, 5).

AR05.20-P-6992-04CD


Ensure they are installed free of tension.
Otherwise, damage to the intake camshaft (6) and exhaust camshaft (7) will occur.

 Install camshaft bearing caps (4, 5) in reverse order at the same point. Tighten bearing cap bolts evenly in steps of one turn each. The intake camshaft (6) and the exhaust camshaft (7) are very fragile.

 Screw/bolt, camshaft bearing cap to cylinder head

*BA05.20-P-1002-01N

11

Install the chain tensioner.

AR05.10-P-7800CD

12

Tighten camshaft sprockets (2).

If camshaft sprockets (2) or intake camshaft (6) or exhaust camshaft (7) were replaced.

 Screw/bolt, camshaft sprocket to camshaft

*BA05.20-P-1001-01N

13

Check basic position of camshafts.

AR05.20-P-6010CD

If the basic position of the intake camshaft (6) and exhaust camshaft (7) is not correct,



Adjust the exhaust camshaft (6) and intake camshaft (7).

AR05.20-P-6020CD

14

Install cylinder head cover.

AR01.20-P-5014CD

15

Install cylinder head cover trim.

 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

 Danger

Risk of explosion caused by fuel igniting. Risk of injury to skin and eyes caused by fuel spraying out at high pressure

Keep all ignition sources out of hazard area.
Do not carry out any work on system when it is pressurized.

AS07.16-Z-0001-01A

16

Check oil leak tightness and check fuel system for leaks with engine running.

17

Connect diagnostic device, read out fault memory, and delete if necessary.



AD00.00-P-2000-04A

 Process and delete stored faults that are attributed to assembly, testing work, removed lines, or a simulation in the fault memories after completion of the work.

 Camshaft

Number

Designation

Engine 651

BA05.20-P-1001-01N

Screw/bolt, camshaft sprocket to camshaft

Stage 1

Nm

55

Stage 2

°

90

 Camshaft

Number

Designation

Engine 651

BA05.20-P-1002-01N

Screw/bolt, camshaft bearing cap to cylinder head

Stage 1

Nm

5

Stage 2

Nm

9