Isuzu NHR 4J Series, Workshop Manual

Page: 74 / 406

GENERAL ENGINE MECHANICAL 6A – 7
NOTE:
After being pressed into the cylinder head, the hot
plugs were provided with surface grinding.
Accordingly, their dimensions are different
individually among them, and take care not confuse
the order of the cylinders
.
When replacing the hot plug with new one:
When assembling a new hot plug, set the knock ball in the
positioning groove on the cylinder side and hit it lightly with
a plastic hammer until the hot plug is set in stably.
With patch attached to the hot plug to prevent it from
being damaged, press it in with a force of 4.5 to 5.5 ton
applied.
After pressing the hot plug, grind its surface to the cylinder
head.
And finally, hit the hot plug lightly with a plastic hammer
and check it for any excessive sinking, protrusion or
backlash.
2) Valve Seat Insert Installation
1. Carefully place the attachment
!
(having a smaller
outside diameter than the valve seat insert) on the
valve seat insert
"
.
NOTE:
The smooth side of the attachment must contact the
valve seat insert.
2. Use the bench press
#
to gradually apply pressure to
the attachment and press the valve seat insert into
place.
NOTE:
Do not apply an excessive amount of pressure with
the bench press. Damage to the valve seat will
result.
Measure the height of the valve guide upper end from the
upper face of the cylinder head.
Valve Guide Upper End Height (H) (Reference) mm (in)
13 (0.51)
NOTE:
If the valve guide has been removed, both the valve
and the valve guide must be replaced as a set.
6A-7-1.tif
6A-7-2.tif