4. ENGINE
4-2-2
Causes and countermeasures to be taken when the compression pressure is less than the limit value.
4-2-2 Adjusting the Valve Clearance
(1) Inspect and adjust the intake / exhaust valve clear-
ance while the engine is in the cold state.
(2) Set the piston in the cylinder to be measured to the
top dead center (TDC) of compression.
(3) Loosen the lock nut and the adjust screw. Check
that the valve cap is free from inclination or foreign
matter.
(4) Insert a thickness gauge between the rocker arm
and the valve cap. Tighten the adjust screw until the
clearance listed below is attained.
Notes :
1. If the valve cap is worn or otherwise damaged in the
head, replace it with a new one.
2.
Check that the valve cap is fitted on the head of
intake/exhaust valve.
No.
Item
Causes
Countermeasures
1
• Filter element of air cleaner • Clogged filter element
• Broken filter element
• Defective filter element seal portion
• Clean the filter element.
• Replace the filter element.
2
• Valve clearance
• Excessive or no valve clearance
• Adjust the valve clearance.
(Refer to Section 4-2-2.)
3
• Valve timing
• Improper valve timing
• Improper valve clearance
• Adjust the valve clearance.
(Refer to Section 4-2-2.)
• Inspect and adjust the valve rocker arm.
(Refer to Sections 4-3-3, 4-3-6 and 4-3-8.)
4
• Cylinder head gasket
• Nozzle gasket
• Gas leak through the gasket
• Replace the gasket.
• Re-tighten the cylinder head and the nozzle at the
specified torque.
(Refer to Section 3-7-2 of Chapter 3.)
5
• Intake/exhaust valve
• Valve seat
• Gas leak due to worn valve seats or
trapped foreign matters
• Sticking of valves
• Lap the valve seats.
(Refer to Section 4-3-1 2).)
• Replace the intake/exhaust valves.
6
• Piston
• Piston ring
• Cylinder
• Gas leak due to scratches or wear of
the piston, piston ring or cylinder
• Do the honing and use oversize parts.
(Refer to Sections 4-3-2 3) and 4-3-4 8).)
Intake / exhaust valve
clearance
Refer to Section "3-2 1) Nominal
and Allowable Values".
Adjust screw
(Adjusting the valve clearance)
Valve clearance
Lock nut
Valve cap
Normal
Abnormal
Summary of Contents for ViO12-2A
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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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