)
e
e
e
,
"
e
n
de
ly
so
be
Ig.
ift
'or
lng
of
(2)
Check
to
be sure
that
the
internal
oil
passages are all clear.
(3)
Using a straightedge and feeler gauge,
check
the
gasketed surface for flatness.
Checking the gasketed surface for flatness
Valve guides
(I)
Take
diameter
measurements
on
valve guide
and stem
to
find
out
the
radial clearance
by
subtraction;
if
the
determined
clearance
exceeds
the
limit, replace
the
guide
or
valve,
or
both.
(2)
To
remove
the
guide for
replacement,
drive
it
out
of
the
cylinder
head
by
giving a
push
to
the
bottom
side
of
the
guide. Use
the
valve guide remover.
To
install
the
replacement
guide, press
it
into
the
hole until its trailing
portion
measures 12 ± 0.5
mm
(0.5 ± 0.02 in.) from
cylinder
head
top,
as
shown
below.
After
pressing
the
guide in,
check
the
radial
clearance by inserting its valve
stem
just
for
a trial:
if
the
clearance is
too
small, ream
the
guide
to
produce
a
proper
radial
clearan~e.
: 12±O.5
Valve
guide
Pressing
in
of valve guide
ENGINE
Valve seats
(I)
Visually
inspect
each valve seat for seating
contact
pattern
and
for damage and,
as
necessary, repair
it
by
lapping
in
the
usually
manner
to
the
seat
angle and
diameter
specified.
Intake side
Exhaust side
Valve seat angle and diameter
(2)
An
insert-type
valve seat in service is
subject
to
beating
action
of
its valve and
might force itself,
though
very gradually,
into
the
cylinder
head,
thereby
presenting a
phenomenon
of
"seat
sinkage," which
is
primarily
due
to
creeping
effect
of
stressed
metal. This sinkage shows up as an incre-
ment
in
the
as-installed
length
of
valve
spring.
Measure
the
length
of
each valve spring in
place and,
if
the
increment
(corresponding
to
the
sinkage)
is
found
to
exceed
the
limit,
replace
the
whole cylinder head.
In measuring
the
as-installed length, it
is
permissible
to
read
the
distance
between
the
bottom
end
of
spring
to
the
top
face
of
spring retainer.
In
such
a case, the thickness
(measured in advance)
of
the
retainer
must
be
subtracted
from
the
reading.
The
retainer
(actually
the
flange) thickness is 1.7 +
0'8
mm
(0.067
+0.0118
in).
Measuring as-installed length of
valve
spring
2-17
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