4. ENGINE
4-3-3
(4) Last, lap the valve using only oil.
Notes :
1. After correcting the valve seat, thoroughly clean the valve and the cylinder head using light oil or the like. Thor-
oughly remove the valve compound or the grindstone powder.
2. For slightly poor contact, take the steps (3) and (4) only.
3) Intake / Exhaust Valve
(1)
Wear and bend of the valve stem
Replace the valve stem if bent or worn excessively. In this case, replace the valve guide together with the valve
stem.
(2)
Valve stem and valve guide
Oil clearance is the difference between the valve guide inside diameter measured with a three-point micrometer or a
cylinder gauge and the stem outside diameter measured with a micrometer. If the oil clearance is near the wear limit,
replace both the intake / exhaust valve and the valve guide with new ones.
Note :
Three-point micrometer : Used for an inside diameter of 4 to 8 mm.
Cylinder gauge : Used for an inside diameter of 6 mm
or more.
(3) Thickness of valve head
Measure the thickness of the valve head with a micrometer.
If the measured value is near the wear limit, replace the
valve with a new one.
Standard
Wear limit
Intake
valve
Stem
outside dia.
Refer to Section "3-2 1) Nominal
and Allowable Values".
Guide
inside dia.
Oil clearance
Exhaust
valve
Stem
outside dia.
Guide
inside dia.
Oil clearance
Standard
Wear limit
Thickness
of valve
head
Intake
valve
Refer to Section "3-2 1) Nominal
and Allowable Values".
Exhaust
valve
Seat width
Valve diameter
Seat angle
Thickness
(Measuring the valve stem outside diameter)
Summary of Contents for ViO12-2A
Page 1: ...SERVICE MANUAL EXCAVATOR ViO12 2A...
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Page 109: ...5 3 1 5 ELECTRIC SYSTEM 5 3 Wiring Diagram...
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Page 117: ...6 HYDRAULIC SYSTEM 6 1 3...
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Page 123: ...6 HYDRAULIC SYSTEM 6 2 1 6 2 Hydraulic Circuit Schematic...
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Page 219: ...6 HYDRAULIC SYSTEM 6 7 8 1 4 3 8 7 12 10 10 15 a b c Loctite 262 0 30Nm 0 45Nm...
Page 348: ...7 ADJUSTMENT AND REPAIR 7 5 31 6 Control Levers Pilot valves Control valve...
Page 349: ...7 ADJUSTMENT AND REPAIR 7 5 32 7 Upperstructure Implement Bucket cylinder Arm cylinder...
Page 351: ...7 ADJUSTMENT AND REPAIR 7 5 34 9 Undercarriage High speed travel solenoid valve...
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Page 360: ...CHAPTER 8 PERIODIC INSPECTION AND SERVICING 8 1 List of Periodic Inspection and Servicing 8 1...
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Page 364: ...CHAPTER 9 FUEL LUBE OIL AND GREASE RECOMMENDED 9 Fuel Lube Oil and Grease Recommended 9 1...
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Page 406: ...CHAPTER 11 REFERENCE DATA 11 1 Specifications for Attachment 11 1...
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