Item
Explanation
I
Inlet valve
X
Exhaust valve
1.
Check TDC position of piston in cylinder A1:
• The piston is at firing TDC when the rocker arms at cylinder A1 are unloaded.
• The piston is at overlap TDC when the rocker arms at cylinder A1 are loaded.
2.
Check valve clearance with cold engine:
• Inlet valves (long rocker arm) = 0.2 mm
• Exhaust valves (short rocker arm) = 0.5 mm
3.
Check all valve clearances in two crankshaft positions (firing TDC and overlap TDC of cylinder A1) as per
diagram.
4.
Use feeler gage to determine the clearance 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.
Release locknut (1).
2.
Insert feeler gage between valve bridge and
rocker arm.
3.
Turn adjusting screw (2) with Allen key until
appropriate valve clearance is set.
4.
Feeler gage (3) must just pass through the
gap.
5.
Tighten locknut (1) to specified torque using a torque wrench. Secure adjusting screw (2) in so doing.
Name
Size
Type
Lubricant
Value/Standard
Nut
M 16 x 1.5 Tightening torque
(Engine oil)
90 Nm +9 Nm
6.
Replace or rectify adjusting screws and/or locknuts which do not move freely.
7.
Check valve clearance.
Final steps
1.
Remove barring tool (→ Page 67).
2.
Install cylinder head cover (→ Page 77).
M015565/03E 2016-02
| Valve Drive | 83
TIM-ID: 0000004352 - 006
