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FIG.
29-(ompressing Valve
Spring
3. Remove the
sleeve, spring re-
tainer, stem
seal,
and valve.
Discard
the
valve
stem
seals.
Identify
all
valve
parts.
CYLINDER HEAD CLEANING
After
the
valves are removed,
clean
the
valve guide
bores
with a valve
guide cleaning
tool.
Use cleaning sol-
vent to remove dirt,
grease,
and
other
deposits.
CYLINDER HEAD INSPECTION
Check
the
cyl inde:
head
for
cracks,
and
the
gasket
surface
for
burrs
and
nicks. Replace the head if
it
is
cracked. Do not plane or
grind
more than 0.010 inch from the
cylinder
head
gasket surface. Re-
move
all burrs
or
scratches
with an
oil
stone.
Cylinder
Head Flatness.
Check
the
flatness of
th
e cylinder
head gasket
surface (Fig. 30).
Valve Seat
RUDoUt.
Check
the
valve
seat
runout with an accurate
gauge (Fig. 31). Follow the
instruc-
tions of
the gauge manufacturer.
Valve Seat Width. Measure
the
valve seat width (Fig. 32).
Reaming Valve Guides. If it
be-
comes
necessary
to ream a
valve
guide
(Fig.
33) to install a valve
with
an oversize
stem.
a
reaming kit
is
available which contains
the follow-
ing reamer
and pilot combinations: a
FIG.
3D-Cylinder Head Flatness
PART 1-1- ENGINES
Tool_13·93 20
~
FIG.
31-Valve Seat Runout
FIG.
32-Valve Seat Width
FIG.
33-Reaming Valve Guides
1-17
0.003-inch O.S.
reamer
with a
stand-
ard diameter
pilot.
a 0.0 IS-inch
O.S.
feamer with a 0.003-inch
O
.S.
pilot,
and
a
0.030-inch
reamer
with a
0.015-
inch
O.S.
pilot.
When
going from a
stand ard
size
valve to an oversize valve, always
use the
reamers
in
sequence.
Always
reface
the
valve
seat
after th
e
valv
e
guide
h
as
b
een
reamed.
Refacing
Valve
Seats.
Refacing of
the valve
seats
should be
closely co-
o rdinated with
refacing
of the valve
face
so that
the
finished
seat
will
match
the valve face and be
cen·
tered
o
This is important
so
that the
valve and seat will
have
a good com-
pression tight fit.
Be
sure
that
the
refacer grinding wheels a re
properly
dressed.
Grind
the
valve
seats
to
a
tnTe
45°
angle (Fig. 34).
Remove
only enough
stock
to clean
up pits, grooves,
or
to
correct the
valve
seat runout.
After
the
seat has been
refaced.
measure
the
seat width
(Fig. 32). Narrow
the
seat, if necessary
to bring
it
within
lim
its.
If
the
valve seat
width
exceeds
the maximum limit,
remove
enough
stock from
the top
edge
and/ or
bottom
edge of
the
seat
to
reduce
the
width
to
specifications
(Fig.
34).
Use
a
30°
angle
grind
ing
wheel
to
remove stock
from the
top
of
the
seats
(raise
the
seats)
and
use
a
60°
angle
wheel
to
remove stock
from the
bottom
of
the seats
(lower
the
seats).
The
finished
valve
seat
should
con-
tact
the
approximate center
of
the
valve
face.
It
is good
practice
to de-
termine where
the valve
seat
contacts
the
face.
To do this, coat the
seat
with
Prussian
blue,
then
set
the
valve
in
place.
Rotate
the valve
with light
pressure.
If the
blue
is transferred to
the center of the
valve
face,
the con-
tact
is
satisfactory.
If
the
blue
is
trans-
ferred to the top
edge of the valve
face, lower the va lve
seat. If the blue
is
transferred to
the
bottom edge
of
the
valve
face.
raise
the valve
seat.
TO
REMOVE
STOCK
fROM
TOP
O
f
SEAT,
USC 30
0
W
HEEL
TO
REMOVE
STOCk
fROM
80TTOM
O
f
SEAT,
USE
60
0
W
HEEL
FIG.
34-Valve Seat Refacing
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