Operator`s manual
1. Rocker
box
section
including
the
rocker
box
flange.
Both
valve
ports
and flanges.
Thermo-
couple
hole.
Spark
plug
holes.
Push
rod
shroud
tube
holes.
Valve
rocker
shaft
cover
flange.
All
other
exposed
threaded
surfaces
in
which
paint
might
accumulate.
c. Spray
a very
light
coatof
zinc
chromate
primer
(. 0005
maximum
thickness)
on
the
cylinder
flange.
See
figure
6-35.
Ifthe
correctamount
of paint
hasbeen
ap-
plied
the
color
of the
paint
will
be
green
with
a
yellow-
ish
tint
and
the metal
will
show
through.
If
the paint
is
too
thick
the
color
will
be zinc
chromate
yellow.
CAUTION
It is
imperative
that the
paint
thickness
on
the
flange
be
held
to
.0005
maximum.
To
measure
the
thickness
of
the
paint
layer,
one
of two
methods
may
be
used.
A
Tinsley
thickness
gage
whichincorporates
a
mag-
netic
needle
and
is
scaled
in
tenth
of
thou-
sandths
is the
most
satisfactory
method.
If
this
type
equipment
is
not
available,
use
a
micrometer
to
measure
the
thickness
of
the
flange
before
and
after
painting.
If the
paint
is
too
thick
it must
be
removed
and
repainted.
Section
6
Cylinders,
Pistons,
and Valve
Train
OVERHAUL
MANUAL
LYCOMING
DIRECT
DRIVE
AIRCRAFT
ENGINES
d.
Mask
off
the
flange
area
as
shown
in
figure
6-35.
Proceed
to
paint
the
cylinder
with
a Phthalate
resin
type
enamel
(AMS3125C
or
equivalent
MIL-E-7729)
properly
thinned
with
Toluene
or equivalent
(AMS3180
or
equivalent
Federal
Spec.
TT-T-548).
e.
Use
a cloth
dipped
in
thinner
to clean
paint
from
all
surfaces
where
paint
may
have
accidentally
ac-
cumulated.
f.
The
best
finish
will
result
if the
cylinder
is
air
dried
for
fifteen
minutes
and
then
baked
in
an
oven
un-
til completely
dry.
6-142.
Intercylinder
Baffles.
(Where
applicable.
) All
intercylinder
baffles
must
be
attachedwith
an "S"
type
retaining
hook
and
a slotted
retainer.
Hook
the
baffle
retaining
hookthrough
the
hole
in
the
baffle.
Place
the
baffle
in
position
beneath
and
between
the
cylinders,
runningthe
hookup
between
the
cylinder
barrels.
Place
a
baffle
retainer
in
place
between
the
cylinders
and
using
a
baffle
installation
tool,
bring
the
retainer
hook
through
the
slot
in
the
retainer.
During
the
operation
the
retainer
is forced
down
until
the
hook
comes
above
the
surface
of
the
retainer
far
enoughto
be turned
and
hooked
over
the
bridge
between
the
slots
in
the
retainer.
NOTE
The
baffles
on
up
exhaust
cylinder
assem-
blies
are
placed
above
and
between
the
cyl-
inders.
The
retainer
is placed
below
and
fastened
in the
same
manner
as
described
above.
Figure
6-34.
Cylinder
Head
Fin
Stabilizers
Angle
Head
- Down
Exhaust
6-141.
Cylinder
Painting.
(All Models
employing
Cyl-
inder
Hold
Down
Plates.
) This
paragraph
is intended
to alert
personnel
to
the
extreme
caution
necessary
when
painting
the
cylinder
base
flange.
Any
excessive
amount
of paint
between
the
cylinder
hold
down
plate
and
the cylinder
flange
will
lead
to a loss
of
torque
on
the
cylinder
base
nuts
and
eventual
stud
and/or
cyl-
inder
failure.
The
following
procedure
should
be fol-
lowed
when
painting
a cylinder:
a.
Remove
all
old
paint
from
the
cylinder.
A vapor
degreaser
is best
suited
for
this
purpose.
b.
Mask
off
the
following
parts
of
the
cylinder:
Mask-
ing
tape,
corks,
plugs,
metal
covers,
etc.
are
acceptable
for masking
purposes.
SPRAY SHADED
AREA
PER STEP -"D"
Figure
6-35.
Cylinder
Flange
Area
6-24
Revised
January,
1971