Operator`s manual
Figure
6-13.
Valve
Showing
Locations
for
Checking
Run-Out
and
Section
for
Measuring
Edge
Thickness
6-34.
VALVE
ROCKERS.
Damaged,
badlyworn,
pitted
or scored
tips
and
push
rod
sockets
warrant
replace-
ment
of the
rocker.
Check
the IDof
the rockerbushing
at
severaldifferent
positions
with
a
flatplug
rejection
gage
(64613).
This
is
adouble-endgage;
be suretouse
the
end
marked
"Rocker
Bushing".
If
the
gage
enters
the
bushing
at any
point,
mark
the
bushing
for
replace-
ment.
6-35.
PUSH
RODS.
Inspect
push
rods
for
wear
or
looseness
of ball
ends.
If ball
ends
are
loose,
replace
the
rod.
Rod
must
be
straight
within
. 010
inch.
6-36.
VALVES.
Remove
the
valves
from
the
cylinder
and
clean
to
remove
soft
carbon
and
examine
visually
for
physical
damage,
damage
due
to
burning
or
cor-
rosion.
Valves
that
indicate
damage
of this
nature
must
not
be
released.
NOTE
Exhaust
valves
(except
Inconel
exhaust
valves)
should
never
be
reused.
Inconel
exhaust
valves
may
be reused
if
they
com-
ply
with
requirements
of
the
following
in-
spection.
6-37.
Do
not
reuse
valve
inwhich
stem
diameter
mid-
way
of
valve
measures
less
than
that
measured
at
the
key
end;
exceptinginconel
valves
which
may
be
0.
002
inch
undersize
on
stem
diameter
as
shown
in figure
6-12.
6-38.
Check
runout
of
valve
face.
See
figure
6-13.
Total
runout
must
not
exceed
.0015
inch.
Do
not
re-
use any
valves
that exceed
this
limit.
6-39.
Measure
edge
thickness
of
intake
valve
heads.
See figure
6-13.
If,
after
refacing,
"A"
is
less
thanthe
limit
showninTable
VI-I,
thevalve
must
notbe
resued.
NOTE
The
edge
of
intake
valve
heads
are
gen-
erally
formedasshowninfigure
6-14.
The
thickness
"A"
can
best
be
measured
with
an optical
comparator;
however,
it
can
be
measured
with
sufficient
accuracy
by
means
of a
dial
indicator
and
a
surface
plate,
as
shown
in
figure
6-15.
Section
6
Cylinders,
Pistons,
and Valve
Train
OVERHAUL
MANUAL-
LYCOMING
DIRECT
DRIVE
AIRCRAFT
ENGINES
FACE
OF VALVE MUST
RUN
TRUE
WITH
STEM
WITHIN
.0015
6-40.
Using
an
optical
magnifier,
examing
the
valve
in
the
stem
area
and
the
tip
for
evidence
of cracks,
nicks,
tool
marks,
or
other
indications
of
damage.
Damage
of
this
nature
seriously
weakens
the
valve,
making
it
liable
to
failure.
Any
valve
having
a nick,
with
ragged
edges
more
than
1/16
inch
inlength
should
not
be re-
used.
A
nick
or
tool
mark
of
any
sort
in
the
keeper
groove
of
an
exhaust
valve
is
sufficient
reason
for
not
reusing
the
valve.
See
figure
6-12.
6-41.
If
superficial
nicks
and
scratches
in the
valve
indicate
that
the
valve
might
be
cracked,
it
should
be
inspected
by
a magnetic
particle
or
dye
penetrant
method.
Dye
penetrant
procedures
should
be
carried
out
strictly
within
the
recommendations
of
the
manu-
facturer
of the
penetrant.
6-42.
Critical
areas
include
the
face
and
tip both
of
which
should
be
examined
for
pitting
and
excessive
wear.
Minor
pitting
on valve
faces
can
sometimes
be
removed
by
regrinding;
otherwisethe
valve
should
be
rejected.
Replace
any
valve
that
has
operated
with
a
collapsed
hydraulic
tappet,
regardless
of the
number
VALVE
FACE.
DO
NOT INCLUDE
WHEN
MEASURING
THICKNESS
Figure
6-14.
Section
Through
Edge
of
Valve
TABLE
VI-I
Intake
Valve
Part No.
60037
66429
LW-11901
67905
Min.
Permissible
Edge
Thickness
.040
inch
.050
inch
Engine
Series
0-235, -290-D
0-435-A
O-290-D2,0-320,
0-360,
IO-360,
VO-360,
0-540
73938
. 060 inch
O-290-D2,
0-320,
AIO-320,
IO-320,
LIO-320,
0-340,
0-360,
IO-360,
HO-360,
HIO-360,
IVO-360,
VO-360,
0-540,
IO-540,
TIO-540
73129
LW-13622
67518
71953
72612
73117
73876
.075 inch
.085 inch
IO-360,
LIO-360,
AIO-360,
10-540,
TIO-540,
LTIO-540,
IO-360,
HIO-360,
TIO-360,
IO-540,
IO-720
6-10
Revised
October
1974