block into the valve spring chamber.
(2) Ream the counterbore to an inside,
Remove the other valve stem guides in
diameter of 0.004 inch smaller than
the same manner.
the valve seat insert (11) to be in-
(2) Use a puller to remove the valve seat
(3) Chill each new insert in dry ice for
ten minutes to reduce its diameter
(1) Place the valve stem guide (12) in
(4) Use a pilot driver to tap the insert
position with the countersunk end
downward. Drive the guide into place
(5) Grind the valves to the new inserts
with top of the guide flush with the
valve chamber. Install the other valve
stem guides in the same manner.
(6) Install the valves (par. 186).
Section Ill. GEAR COVER AND TIMING GEARS
b. Cleaning, Inspection, and Repair.
(1) Clean all parts in an approved clean-
The gear cover, located on the front of the
ing solvent and dry thoroughly.
engine, encloses the timing gear train. The
(2) Inspect the gear cover for cracks,
timing gear train consists of the camshaft gear,
breaks, distortion, a n d damaged
crankshaft gear, idler gear, oil pump gear, and
threads. Repair cracks by welding
magneto gear. The governor and magneto gears
and retap damaged threads. Replace
can be removed from the gear train without
a gear cover damaged beyond repair.
removing the gear cover. The remaining gears,
with the exception of the crankshaft gear, can
(3) Inspect all other parts for distortion
be removed after removal of the gear cover.
and damaged threads and replace if
189. Gear Cover
(1) Install the plunger button (8, fig. 34)
(1) Remove the magneto (par. 115).
and the timing hole plug (7) in the
gear cover (10).
( 2 ) Remove the air shrouding group
(pars. 118 and 119).
(2) Press the oil seal (9) into the gear
(3) Remove the governor (par. 135).
(3) Position a new gasket (4) and the
(4) Drain the oil from the engine into a
gear cover (10) on the gear cover
spacer (2) and install the two head-
(5) Drive the two headless straight pins
less straight pins (1).
(1, fig. 34) from the gear cover (10).
(4) Secure the cover in place with the 10
(6) Remove the 10 bolts (5) and lock-
lockwashers (6) and bolts (5). In-
washers (6) that secure the gasket
stall the 2 remaining lockwashers and
(4) and the gear cover to the gear
bolts from the rear top side of the
cover spacer (2). Remove two addi-
gear cover. Tighten the bolts to 14 to
tional belts and lockwashers from the
18 ft-lb torque.
rear top side of the gear cover spacer
(5) Fill the engine crankcase with the
and remove the cover and gasket from
proper grade oil. Refer to table 1.
(6) Install the governor (par. 135).
(7) Remove the timing hole plug (7) and
p l u n g e r button (8) from the gear
(7) Install the air shrouding group (pars.
118 and 119).
(8) Remove the oil seal (9) if defective.
(8) Install the magneto (par. 115).