Komatsu 170-3 Series Shop Manual page 389

REPAIR AND REPLACEMENT OF PARTS
TESTING AND INSPECTING
Inspection item
A. Cracks, leakage from
cylinder head
B. Distortion of top, bot-
tom surface of cylin-
der head
C. Damage to injec-tion
nozzle seat surface,
contact width
D. Protrusion of injector
E. Damage to valve seat
surface or loosening of
seat
F. Sinking and protrusion
of valve (both intake
and exhaust)
G. Thickness of valve
head
15-4
(7)
Judgement standards
• Check for cracks (ext ernal color check)
• Check for water leakage with air pressure test
(294 – 343 kPa {3.0 – 3.5 kg/cm
• Water pressure test (294 – 343 kPa {3.5 – 4.0 kg/cm
• Tolerrance : 0.1
• Dent of seat surface
• Check contact between valve and seat surface
• Airtighteness test
• Tap cylinder head and chek for looseness
TESTING AND INSPECTING CYLINDER HEAD
2
}, 30sec.)
Permissible range: 2.42 – 2.92
Standard value
-0.39 (sinking) to
0.21(protrusion)
• Thickness of valve head
Standard value
Intake valve 3.2
Exhaust valve 3.3
• Angle of seat surface "a"
°
Intake valve: 30
°
Exhaust valve: 45
Remedy
Replace
2
}, 10 min.)
Grind to correct
Machine to repair
or replace
Replace cylinder
head or injector
Correct seat sur-
face or
replace valve
seat
Repair limit
Replace valve or
-0.80 (sinking)
valve seat
Repair limit
2.7
2.9
Replace
170-3 SERIES
Unit: mm