Operator`s manual
Section
7
OVERHAUL
MANUAL
Crankcase,
Crankshaft,
and
Reciprocating
Parts
LYCOMING
DIRECT
DRIVE
AIRCRAFT
ENGINES
SLUDGE
TUBES
TO THESE
DIMENSIONS
REMOVE
EXPANSION
PLUG
FOR
CONSTANT
SPEED
OPERATION
MODEL
DIMENSION
"A"
DIMENSION
"B"
0-235,
0-290
0-320,0-340
0-360
0.
20 inch
0.20
inch
0.25
inch
0.
20
inch
0.20
inch
0.31
inch
Figure
7-17.
Dimensions
to
Drive
Sludge
Tubes
(Four
Cylinder
Engines)
side
of the
counterweight.
Note
that
washers
are
in-
stalled
with
the
chamfered
side
in
toward
the
roller
and
the
circlip
with
the
sharp
side
toward
the
outside
(see
figure
7-19)
and
gap
in
position
as shown
in figure
7-
20.
Insert
one
end
of the
counterweight
retaining
ring
gap
gage
(P/N
64892)
between
the
ends
of
the
retaining
ring,
making
sure
the
gage
is
resting
on the
bottom
of
the
groove.
The
gage
must
pass
between
the
ends
of
the
retaining
ring
and,
when
rocked
back
and
forth,
must
clear
the
inside
edge
of the
top
of
the
retaining
ring.
If the
gage
does
not
pass
freelybetween
the
ends
and
under
the
top
of
the
ring,
the
ring
is not
seated
properly.
Make
sure
all
rings
are
properly
seated.
Consult
the
latest
edition
of Service
Instruction
No. 1012
for
proper
location
of
each
counterweight
on
the crank-
shaft.
7-67.
Connecting
Rods.
Assembletwo
new
connecting
rod
bolts
in
each
connecting
rod
cap
and
install
new
bearing
inserts
in
the
connecting
rod
and
connecting
rod
cap,
making
sure
the
tang
of
each
bearing
insert
enters
locating
slot
in
cap and
connecting
rod.
Assem-
ble
each
connecting
rod
assembly
and
tighten
nuts
moderately
tight.
Measure
the
ID
of each
bearing
and
check
for
clearance
against
measurements
taken
pre-
viously
on the
diameter
of
crankpin
journals.
NOTE
Connecting
rods
are
marked
at manu-
facture
with
the
part
number
followed
by
a
letter
(A
through
E)
designating
weight
groups.
It is
recommended
that
replace-
ment
sets
of
rods
be of
the
same
weight
classification.
Individual
rods
may
be
re-
placed
by
a service
rod
bearing
the
letter
7-68.
Place
the
crankshaft
on
a
suitable
support
on
the
bench
so
that
all
crankpins
are
free
for
installa-
tion
of
connecting
rods.
Disassemble
connecting
rods
after
checking
bearing
ID,
thoroughly
coat
both
in-
serts
and
the
crankpin
journals
with
preservative
oil
and
assemble
rods
on
their
respective
crankpins.
The
order
of
assembly
should
be
such
that
the
numbers
stamped
on
the caps
and
rods
will
be
down
(toward
the
sump).
7-69.
There
are
two
types
of
connecting
rod
bolt
and
nut
assemblies
employed.
One
is tightened
to a
speci-
fied
torque
and
the
other
to
a stretch
length.
When
tightening
to
a
stretch
length
alternately
tighten
the
nut
and
check
the
length
using
stretch
bolt
gage
(P/N
64945).
If the
stretch
limit
is
exceeded,
the
connect-
ing
rod
bolt
must
be replaced.
7-70.
Camshaft
(With
Separate
Gears).
See
figure
7-5.
On
six
and
eight
cylinder
engines
assemble
the
Wood-
ruff
key
(3),
install
the
governor
drive
gear
(2)
and
secure
with
retaining
rings
(1).
7-71.
(a)
Camshaft
(with
separate
gears)
ExceptO-235
and
0-290
- Secure
the
tachometer
shaft
(16)
to
the end
of the
camshaftwith
a pin
(15).
Assemble
the
camshaft
gear
(14)
over
the
stepped
dowel
(12)
on
the
camshaft
and
insert
the
spacer
(18)
into
the
center
recess
of the
camshaft
gear.
As-
semble
the
breather
slinger
(19)
and
secure
as-
sembly
to
the
camshaft
gear
with
lockplate
(20)
and
hex
head
screw
(21).
(b) (0-235,
0-290)
-
The
tachometer
shaft
is
in-
stalled
in
the
accessory
housing.
Assemble
the
tachometer
drive
pin
(15)
in the
camshaft.
As-
semble
the
camshaft
gear
(14)
over
the
stepped
dowel
(12)
and
secure
to
the
camshaft
with
lock-
plate
(20)
and
hex
head
screw.
7-72.
(a) Camshaft
(with
integralgears)
Except
0-235
and
0-290
-
Assemble
tachometer
shaft
centering
spacer
and
install
pin
and
tachometer
shaft,
se-
cure
with
retaining
ring.
(b)
(0-235,
0-290)
- Install
pin
and
tachometer
shaft
in
camshaft
gear
and
secure
with
retaining
ring.
7-14
Revised
January,
1971