Komatsu 170-3 Series, Руководство по ремонту, Страница: 421 / 454

170-3 SERIES
15-15
REPAIR AND REPLACEMENT OF PARTS
GRINDING VALVE
1. Grinding the seat surface
•
Grind the seat sutface with valve refacer I.
a
Angle of valve seat: intake valve: 30
°
EXhaust valve: 45
°
2. Checking after grinding
•
Confirm that the thickness of the valve head,
protrusion of the valve, and the contact surface
of the valve seat are within specification.
a
Thickness of valve head
Repair limit
Intake valve: 2.7 mm
(Standard size 3.2 mm)
Exhaust valve: 2.9 mm
(Standard size 3.3 mm)
a
Sinking of valve Standard:
(sinking) 0.39
–
(protrusion) 0.21 mm
Repair limit: (sinking) 0.8mm
a
Check the contact of the valve with the seat
surface using one of the following methods.
•
Coat the seat surface of the ground valve
thinly with red lead (minium), insert it in
the valve guide, push lightly against the
valve seat insert surface, and confirm
that the contact is uniform without any
breaks.
• Make marks a with a pencil on the seat
surface of the ground valve as shown in
the diagram, insert it in the valve guide,
push lightly against the valve seat insert
surface, and rotate 10
°
. Check that the
pencil marks have been erased uniformly
around the whole circumference.
(7)
GRINDING VALVE
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