Isuzu A-4BG1 Workshop Manual page 66

A
ENGINE
ASSEMBLY II
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Valve Depression
1. install the valve @to the cylinder head 0.
2. Use a depth gauge or a straight edge with steel rule
to measure the valve depression from the cylinder
head lower surface.
If the measured value exceeds the specified limit,
the valve seat insert and/or valve must be replaced.
If the valve is replaced, the valve guide must be also
replaced.
mm (in)
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Standard
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Limit
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Intake and Exhaust
Valve Depression
1 .o (0.039) 2.5 (0.098)
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Valve Contact Width
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1. Inspect the valve contact faces for roughness and
unevenness.
Make smooth the valve contact surfaces.
2. Measure the valve contact width.
If the measured value exceeds the specified limit,
the valve seat insert must be replaced.
mm (in)
1 Standard 1
Limit
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Valve Contact Width ( 1.5 (0.059) ( 2.0 (0.078)
Valve Seat insert Replacement
Valve Seat Insert Removal
1. Arc weld the entire inside circumference @ of the
valve seat insert @.
2. %llow the valve seat insert to cool for a few minutes.
This will invite contraction and make removal of the
valve seat insert easier.