Isuzu AA-6HK1T, Workshop Manual

Page: 102 / 242

ENGINE MECHANICAL 6A–51
Valve Contact Width
1. Check 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 valve
contact width, the valve seat insert must be replaced.
Valve Contact Width
Intake Valve
Standard: 2.5 mm (0.098 in)
Exhaust Valve
Standard: 2.0 mm (0.079 in)
Valve Seat Insert Removal
1. Arc weld the entire inside circumference (1) of the
valve seat insert (2).
2. Allow the valve seat insert to cool for a few minutes.
This will invite contraction and make removal of the
valve seat insert easier.
3. Use a screwdriver (3) to pry the valve seat insert
free.
Take care not to damage the cylinder head (4).
Valve Seat Insert Installation
1. Carefully place the attachment (1) (having a smaller
outside diameter than the valve seat insert) on the
valve seat insert (2).
CAUTION: The smooth side of the attachment must
contact the valve seat insert.
Carefully remove carbon built-up and other foreign
material from the cylinder head insert bore.
2. Use a bench press (3) to gradually apply pressure to
the attachment and press the valve seat insert into
place.
CAUTION: Do not apply an excessive amount of
pressure with the bench press. Damage to the valve
seat insert will result.
2
1
014EY00064
014EY00065
3
1
2
4
011EY00070
3
1
2
011EY00071