Overhaul Manual
O-360 and IO-360 Series Engines
27
© March 2005 Superior Air Parts Inc.
72-00-13
Repair Procedures
REPAIR NO. 9
SPARK PLUG THREADED INSERT
Spark Plug Threaded Insert Replacement
Spark plug threaded inserts that were rejected
during inspection must be removed and
replaced as described in this section. Use an
extraction tool to remove the rejected insert as
follows:
(1) Insert the tool in the spark plug hole so
that the edges of the tool cut into the top
thread of the insert.
(2) Rotate the tool counterclockwise to
unscrew and remove the threaded insert
from the hole.
Inspect the condition of the tapped hole after
removal of the insert in accordance with the
Inspection and Check section of this manual.
Assemble the insertion tool with new insert as
follows:
(1) Withdraw the mandrel portion of the tool
beyond the recessed section of the
sleeve. Place insert into the recess
area.
(2) Allow the mandrel to advance to engage
its slotted end with the tang of the insert.
(3) Rotate the mandrel clockwise and press
slightly. This engages the insert in the
threaded end of the sleeve.
(4) Continue to rotate the mandrel while
holding the sleeve. This secures the
insert firmly on the insertion tool.
(5) Wind the insert through the threaded
portion of the tool sleeve to within one-
half turn of the end of the coil.
(6) Keep the insert tight on the tool to
prevent unwinding and facilitate the
installation of the insert. Wind the insert
so that the adjacent turns of the insert
are in contact with each other. This
eliminates the possibility of crossed
threads.
(7) Screw the insert into the hole.
(a) Be sure that the first coil of the
insert picks up the first thread of the
hole. As the tool is turned, the
insert will advance into the hole.
(b) When the face of the sleeve is
approximately 0.13 in. from the face
of the boss, the inserting tool should
be held tightly by the handle. The
sleeve must be rotated
counterclockwise which will free the
left half turn of the insert.
(c) Slide the sleeve toward the top of
the mandrel and check that the top
of the insert projects above the
boss.
(d) Rotate the mandrel until the insert
disappears from sight. Stop the
turning action and remove the tool.
(e) The top of the insert should be one
half turn from the face of the boss
and the tang end should not
protrude into the combustion
chamber.
(8) Set the insert as follows:
(a) Break off the tang of the insert at the
location of the notch.
(b) Use an expander tool to secure the
insert in the plug hole. Set the limit
of expansion by fixing the stop nut
on the expanding tool at the correct
position.
(c) Assemble a staking sleeve over the
mandrel until the sleeve meets the
boss. Stake the insert by striking
the top of the sleeve a light blow
with a hammer. This will create a
slight chamfered edge around the
edge of the tapped hole.
(d) Remove the staking sleeve, release
the adjusting screw, and remove the
expanding mandrel from the insert.
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