Nanni T4.155 seriers, Руководство по ремонту

Страница: 106 / 191

60300140 (
indice A
) 4 CYLINDERS WORKSHOP MANUAL 106/191
7. EXAMINE AND GRIND VALVES
a. Only grind valves with an electric grinder if surface pitting or
carbon deposits need to be removed.
b. Make sure that the angle of the sealing surface of valves is
ground to the indicated dimension.
Valve sealing surface angle:
45.5°
c. Measure the thickness of the valve head.
Nominal thickness of valve head:
Intake: 1.6
mm
Exhaust: 1.7 mm
Valve head minimum thickness:
Intake: 1.1
mm
Exhaust: 1.2 mm
If the thickness of the valve head is less than the minimum dimension,
replace the valve involved
d. Measure the overall length of the valves.
Nominal overall length of the valve:
103.29 – 103.69 mm
Minimum overall length of the valve: 102.79 mm
Replace the valve involved when the overall length of the valve is less
than the minimum dimension.
e. Measure the degree of wear on the valve stem end.
Grind the end of the valve stem end with an electric grinder if worn, or
replace the valve.
REMARK:
Make sure not to remove more material than
necessary as it may no longer be possible to obtain
the overall minimum length of the valve stem.