Cessna 177 SERIES Service Manual

NOTES 11-61. REPLACEMENT INTERVAL.
a. SLICK.
These magnetos
cannot be overhauled
Wire feeler gages are recommended when in the field. The coil, capacitor and breaker assem-
checking
contact point clearance.
bly are non-replaceable.
As a good maintenance
practice and to
have the benefit of good
ignition at all
* No attempt should be made to stone or dress times, it is recommended that the magnetos be re-
contact
points.
moved at 900 hours
of magneto time and new
exchange
magnetos
installed.
*
If the above conditions
are met and within
tolerance,
the magneto is
timed internally
11-62. MAGNETO-TO-ENGINE
TIMING.
and
ready for installation.
If the above
a. SLICK. The
magneto must be installed
with its
conditions are not within tolerance, proceed
timing marks correctly aligned,
with number one
to step
8.
cylinder on its compression stroke and with
the num-
ber one
piston at its advanced
firing position. Refer
8.
While holding
the rotor
shaft, loosen
the
to
paragraph
11-12 for
the advanced
firing position
screw securing
breaker contact
cam to rotor
shaft
of number one
piston. To locate
the compression
and back screw
out approximately
half way. Place
stroke of
the number
one cylinder.
remove the
lower
the
end of a broad
bladed screw
driver between
the spark
plug from number
2, 3 and 4
cylinders. Re-
bottom of
the cam
and housing.
Strike
the screw
move
the upper
spark plug
from
number 1
cylinder.
driver handle
with a sharp
downward blow
to "pop"
Place the thumb
of one hand over
the spark plug
hole
the cam loose
from taper
of shaft,
of number
one cylinder
and rotate
crankshaft
in the
9.
Rotate cam
until breaker
contact
cam fol-
direction
of
normal rotation
until
the compression
lowers are
on the high
point of
cam lobes.
Adjust
stroke
is indicated
by positive
pressure
inside the
breaker
points to
obtain a clearance
of
0.016±0.002
cylinder
lifting
the thumb
off the spark
plug hole.
inch
and 0. 016=0.
004 inch on LEFT
and RIGHT
con- After
the compression
stroke is
attained, locate
tacts
respectively.
Tighten breaker
contact securing
number
one piston at
its advanced firing
position.
screws to 20-25
lb-in.
Locating
the advanced
firing position
of number
one
10.
Repeat step
3.
piston
may be obtained
by rotating
the crankshaft
11.
While holding
rotor
shaft in this
EXACT
po- opposite
to its
normal direction
of
rotation until
the
sition, rotate
the breaker
contact
cam in the
opposite
piston is
approximately
30 degrees
before top
dead
direction
of rotation
a few
degrees
BEYOND
where
center (BTC)
on the
compression
stroke
of number
the
breaker
contacts
close,
then
rotate
cam in
the
one
cylinder.
Then
rotate
crankshaft
in its
normal
normal
direction
of rotation
until
the breaker
contacts
direction
of rotation
to align
the timing
mark
on the
just
begin to
open.
Point opening
should
be
deter-
FORWARD
face
of the
starter
ring gear
support
with
mined
by the use
of a timing
light.
(Bendix
Part No.
the
drilled
hole in the
forward
end of
the starter,
11-9110
or equivalent.
)
making
sure the
final
motion
of the
ring
gear is
in
12.
While
holding
cam in
this EXACT
position,
the direction
of normal
rotation.
push cam
on rotor shaft as far
as possible with the
fingers.
Tighten
cam
securing
screw
thereby
draw-
NOTE
ing the cam down evenly and tightly. Torque cam
securing
screw
to
16-20 lb-in.
The starter
ring
gear must
always
be in
this position when
either magneto
is
NOTE
locked
in
position.
Extreme
care must be
exercised in this
When the cylinder
is in the
correct firing
position,
operation.
If cam adjustment
is changed
install and time
the magneto
to the engine
in the
in
the slightest
degree,
the
timing
of the
following
manner.
magneto will be
thrown off. Do not
drive
cam
on rotor
shaft
with a mallet
or
other
NOTE
instrument.
Install the magneto drive coupling retainer
13. Recheck
timing to make
sure both
sets of
and rubber
bushings into
the magneto
drive
breaker contacts
begin to open
within the width
of
gear hub
slot. Insert the
two rubber bush-
the L
("E" gap) mark
and that
the contact
point
ings into
the retainer
with chamfered
edges
clearance
is
in accordance
with dimensions
in
step 7.
toward
the operator
when
looking into
the
magneto mount pad on the engine.
NOTE
1.
Remove the ventilating
plug from the bottom
When reinstalling
the inspection
hole plugs,
of the
magneto. The
ventilating plug
in the top of
the
make
sure the
ventilated
plugs
are installed
magneto
need
not be
removed.
in the
ends
of the magneto.
Torque
plugs
to
2.
Rotate magneto
shaft until
timing
marks
are
12-15
lb-in.
visible
through
the
ventilation
plug
hole.
Change 2 11-23

Cessna 177 SERIES Specifications

General

Manufacturer	Cessna
Engine Type	Piston
Wingspan	35 ft 6 in (10.82 m)
Seating Capacity	4
Number Built	4, 295
Engine	Lycoming O-360
Horsepower	180 hp
Maximum Takeoff Weight	2, 500 lb (1, 134 kg)