Checking valve clearance at two crankshaft positions
1.
Check TDC position of piston in cylinder A1:
• If rocker arms on cylinder 1 bank A are unloaded, the piston is in firing TDC.
• If rocker arms on cylinder 1 bank A are loaded, the piston is in overlap TDC.
2.
Check valve clearance with cold engine:
• Inlet (I) = 0.3 mm;
• Exhaust (X) = 0.4 mm.
3.
Check all valve clearances at two crankshaft positions (firing TDC and overlap TDC) according to the
table below.
Position
Cylinder
1
2
3
4
5
6
7
8
9
10
12V
Firing TDC in cylinder A1
Bank A
I X
I – – X I – – X – –
Bank B
I –
– – – X I –
I X – X
Overlap TDC in cylinder A1
Bank A
– – – X I – – X I –
I X
Bank B
– X I X
I – – X – –
I –
16V
Firing TDC in cylinder A1
Bank A
I X – X – X I – – X I –
– – – –
Bank B
I – – X – –
I –
I X
I –
I X – X
Overlap TDC in cylinder A1
Bank A
– –
I –
I – – X I – – X I X
I X
Bank B
– X I –
I X – X – – – X – –
I –
I
Inlet: Inlet valve adjustment admissible
X
Exhaust: Exhaust valve adjustment admissible
–
Valve adjustment inadmissible
4.
Use feeler gauge to determine the distance between valve bridge and rocker arm.
5.
If the deviation from the specified value exceeds 0.1 mm, adjust valve clearance.
Adjusting valve clearance
1.
Loosen locknut (1) and unscrew adjusting
screw (2) by a few threads.
2.
Insert feeler gauge (3) between valve
bridge and rocker arm.
3.
Readjust adjusting screw (2) so that the
feeler gauge (3) just passes through the
gap.
4.
Tighten locknut (1) with torque wrench to the specified tightening torque, holding the adjusting screw
(2) with Allen key to prevent it from turning.
Name
Size
Type
Lubricant
Value/Standard
Locknut
M12x1
Tightening torque
(Engine oil)
50 Nm +5 Nm
M015655/05E 2015-06
| Task Description | 89
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