Ford Thunderbird 1957 - Valve Mechanism; Cleaning and Inspection; Valve Face Runout; Valve Stem Clearance

1-14
Chapter
1
General Engine
Service
sealer
and
install
it
with
the
flange
facing
out.
Drive the
plug
in
until
the
flange
is
flush or
slightly
below the
casting
surface.
To
remove
the
water
plug,
drill
a
Vfe-inch
hole
in the
center
of
the
plug
and
remove
it
as shown in
Fig.
10.
Sending
Unit
Adapter
The
sending
unit
adapter
is
installed as shown in Fig.
11.
Clean
the adapter
recess
thoroughly. Coat
the
adap
ter
with
water resistant
sealer and
install it
with
the
undercut toward the
inside
of
the
cylinder
head.
Drive
the
adapter
in until
it
is
flush
with the
casting
surface.
To
remove the
adapter,
thread
the impact
hammer
handle into
the
adapter,
then
tighten the
lock
nut
against
the
adapter
(Fig.
12).
Remove the
adapter
by
using
the
slide
hammer.
5.
VALVE MECHANISM
The
critical inspection
points
and
tolerances
of
the
valve
are illustrated in Fig.
13. Both
the intake and
exhaust valves
are the
rotating
type
which
incorporate
umbrella-type valve
stem
seals.
Cleaning
and Inspection
Remove all
carbon
and
varnish from the valve with
a fine
wire brush or
buffing
wheel.
Inspect the
valve face
and
the edge of
the valve
head
for
pits,
grooves,
scores,
or
other
defects.
Inspect
the stem for a bent
condition
and the end
of
the
stem
for grooves or
scores.
Check the
valve head
for
signs
of
burning
or
erosion, warpage,
and
cracking.
Defects,
such
as minor
pits,
grooves, etc.,
may
be removed.
Discard
valves that
are
severely
damaged.
Inspect the
valve
springs,
valve
spring
retainers,
locks,
and
sleeves
for defects. Discard
any
defective
parts.
VALVE
FACE RUNOUT.
Check the valve face runout
(Fig.
14).
The recommended
limit
for runout is
0.0015
inch
total
indicator reading.
The
wear limit
is 0.002
inch
total
indicator reading.
VALVE
STEM
CLEARANCE.
Check the
valve
stem
to
valve
guide
clearance
of
each
valve
in its
respective
valve guide
with the
tool
shown
in
Fig. 15
or
its
equivalent.
Install
the
tool on the
valve
stem until
fully
seated
and
tighten
the
set
screw,
then permit the
valve to
drop
away
from its
seat
until
the
tool
contacts
the
upper
-
Va"
MINIMUM
REFER
TO
SPECIFICATIONS
FOR
CORRECT
DIAMETER
z
i
DO
NOT
REMOVE
MORE
THAN 0.010
INCH
101
4-
A
surface
of
the valve
guide.
Position
a
dial
indicator
with
a flat
tip
against the
center portion
of the
spherical
sec
tion
of
the tool at
approximately
90
to
the
valve
stem.
Move the tool
back
and
forth on a
plane
that
parallels
normal rocker
action
and
take the
indicator
reading
without
lifting
the tool
from the valve
guide
upper
sur
face. Divide
the
indicator
reading by
2
(division factor
of the
tool)
to
obtain the
actual
stem clearance.
The recommended
intake valve
stem
clearance
limits are 0.001-0.0024
inch.
The wear limit is
0.0045
inch. The
recommended
exhaust valve
stem clearance
limits are 0.0023-0.0037
inch.
The wear limit is 0.0065
inch. If
the
clearance approaches
the
wear
limit,
try
a
new valve.
VALVE SPRING
PRESSURE. Check the
spring
for
proper
pressure
(Fig. 16).
The
springs should exert
a
pressure
of
71-79 pounds
when
compressed
to
1.780
inches
(wear limit
64
pounds)
or a pressure
of
161-177
pounds
when
compressed
to 1.390 inches (wear limit
145 pounds).
Weak
valve
springs
cause
poor engine
Model TV-2 Runout
Gauge
1015-A
f/g.
73
Critical
Valve
Tolerances
Fig.
14
Valve
Face
Runout