7.5 Valve Drive
7.5.1 Valve clearance – Check and adjustment
Preconditions
☑
Engine is stopped and starting disabled.
☑
Engine coolant temperature is max. 40 °C.
☑
Valves are closed.
Special tools, Material, Spare parts
Designation / Use
Part No.
Qty.
Feeler gage
Y4345893
1
Engine barring gear
F6783914
1
Ratchet
F30006212
1
Double-head box wrench
F30002800
1
Offset screwdriver
F30002816
1
Socket wrench
F30030450
1
Torque wrench, 10-60 Nm
F30510423
1
Measuring device
Y4345888
1
Preparatory steps
1.
Remove air filter (→ Page 101).
2.
Remove cylinder head cover (→ Page 85).
Positioning A1 piston at TDC
Note:
With cylinder head and valve gear installed.
1.
Install dial gage (2) under preload in meas-
uring device (4) and clamp with screw (1).
2.
Install measuring device (4) in cylinder
head and secure using knurled-head
screw (3).
3.
Zero dial gage (2).
4.
Turn engine using barring gear until piston
A1 reaches firing TDC.
Result:
The piston is at firing TDC when both rock-
er arms are unloaded, i.e. have clearance.
Checking valve clearance at two crankshaft positions
1.
Check TDC position of piston in cylinder A1:
• If the rocker arms are unloaded on cylinder A1, the piston is in firing TDC.
• If the rocker arms are loaded on cylinder A1, the piston is in overlap TDC.
2.
Check valve clearance with cold engine:
• Inlet (I) = 0.3 mm;
• Exhaust (X) = 0.4 mm.
M015590/06E 2014-03
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