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Section
5-Rocker Mechanism,
Cylinder Heads,
Valves, Valve lash
Adjustment, and
Valve
Timing
19
Irl'!,-_MA.XIMUM
V
ALVE
FACE
RUNOUT
0.002
CHECK
/
REFER
TO SP ECIFICATIONS
FOR
CORRECT DIAMETER
f
FOR
BEN
T
STEM
6480
Fig.
J
8-Critical
Valve Tolerances-Typical
cap
on a
smooth surface.
The critical
tolerances of the
valve are
illustrated
in
fig.
18.
(b)
REF ACING VALVE
SEATS.
Grind
the
valve seat
(fig.
19) to
a
true
45
0
angle.
Remove
only enough
stock to
clean up
pits
or
grooves.
If the
valve seat
width
exceeds specifications, remove
just
enough stock
from
the
top and
/
or
bottom
edge
of
the seat to reduce
the
width to
specifi
cations.
Use
a
30
°
angle
wheel to re-
move
stock
from
the bottom of
the
seat and a
60
°
angle
wheel
to
remove
stock from
the
top
(fig. 20
or 21)
.
Keep
the
seat as
near
to
the
center
of
the
va lve
face
as
possible. P
lace
Prussian B lue
on
the valve
seat and in-
stall
the va
lv
e
to check the point
of
contact.
After
refacing valves and
seats,
it
is
good
practice
to lightly
lap
in
the
valves with
a
medium
grade lap-
ping
compound to
match
the
seats.
(c)
VALVE
SEAT
INSERT
REPLACEMENT.
To
remove
the
exhaust
valve
insert from
the ECR
272, 302 or
the
332
cubic
inch
engine,
invert
the
head and
insert
a
drift
through
the
exhaust
valve port, then
drive
the
30°
ANGLE WHEEL
FOR BOTTOM
OF
SEAT
60°
WHEEL
FOR
SEAT
,
6605
Fig
.
19-R
el
acing
Valve Seat-Typical
REFER TO
SPECIFICATIONS
6292
fig.
20-Valve
Seat Width-Typical
seat
out.
Counterhore
the
insert recess
to specifications
in
the
manner
shown
in
fig.
22.
Cut slightly (0.001.0.002 inch)
below
the
old
counterhore
depth
to clean
up this
face.
Clean
out
chips
and a
ll
oil
from the recess.
,/"-t-
"m'R
TO
SPECIFICATIONS
6293
fig
.
2J-Exhaust
Valve
Seat
Width-/nsert ·Type
Seat
Shown
Chill the
oversize insert
and the
installation
tool in
dry
ice for
V2
hour.
Position the
insert
on the
tool
with
the
small radius
on
the
outer
edge facing outward.
Pilot the
driving tool in the
valve guide,
then drive the
insert
into the
counte
r
bore until
it is
fully
seated.
Do
not
peen the
area
around the
insert.
R
eface
the
new
valve seat
insert.
CAUTION:
T
h
e
installation of the
inse
rt must
be
perfornted immediately upon
removal of
th
e
tool
and
insert fro,n th
e
dry
ice
.
Protect
the
hands with
gloves when handling
the
chilled
insert
and
tool.
COUNTER
BORE
TO
ENGINE
SPECIFICA
li
ONS
~~~r-~-------------l~~~~
EXHAUST
VALVE PORT
TRUE UP
THIS
FACE
LIGHTlY
Fig
.
22
-Coun
terbore lor
Oversize Insert
6294
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