c. Install the woodruff key in the oil-pump
f. Examine the gear-cover spacer for breaks
shaft.
or cracks. Replace a defective gear-cover spacer
d. Slide the idler gear (29, fig. 28) over the
and its gasket.
idler gear stud (28) with the timing marks to-
g. Check the hardware for rust and bad
ward the shoulder of the idler gear shaft. Us-
threads; replace any defective hardware.
ing a suitable fiber hammer, carefully drive the
idler gear shaft into the case. Be sure that the
108. Installation of Timing-Gear Train
oil groove is facing upward. The single mark
a. Position the camshaft gear (5, fig, 32) on
on the idler gear should line up with the sin-
the end of the camshaft. The three holes in
gle mark on the crankshaft gear, Take care to
the camshaft and the gear are staggered in such
allow an end clearance of approximately 0.005
a manner that they are lined up in only one
inch. Install the setscrew in the crankcase,
position. At this position, the timing marks
near the magneto, to secure the idler gear
should aline with the mark on the crankshaft
shaft.
gear. Secure the camshaft gear in place with
e. Install the oil-pump drive gear as in-
the three capscrews (7) and the three lock-
strutted in paragraph 99f.
washers (6). Tighten to 14-18 foot-pounds
f. Check the positions of all the gears and
other components of the gear train, and in-
stall the gear cover in place.
b. Install the thrust-plunger spring (9) and
g. Lubricate as instructed in the lubrication
the thrust plunger (8) in the hollow end of
order,
the camshaft.
Section XI. CONNECTING RODS AND PISTONS
f. Push the piston and connecting rod out
109. Description
through the top of the cylinder bore. Be care-
The pistons are made of heavy duty alloy
ful not to scratch or mar the bore. Reassemble
castings, and are equipped with two compres-
the connecting-rod cap loosely on the connect-
sion rings, one scraper, and one oil-regulat-
ing rod.
ing ring. The upper end of the connecting rod
Note. The connecting rods and caps are matched
is fitted with a hard bronze bushing. The end
and must be paired together to insure correct installa-
of the connecting-rod bearing is directly bab-
tion. The caps and rods are marked with their respec-
bitted and fitted with laminated shims for ad-
tive cylinder numbers.
justing.
111. Disassembly of Connecting Rod
and Piston
110. Removal of Connecting Rod and
a. Remove the piston rings from the pis-
Piston
tons.
a. Remove the cylinder heads (par. 101a).
b. Remove the retaining rings (6) and push
b. Remove the oil pump (par. 99b)
the piston pin (5) out from the piston (4) and
c. Remove the carbon and ridge at the top
connecting rod (8).
of the cylinder bore with a ridge reamer.
c. Remove the piston-pin bushing (7). Place
d. Turn the crankshaft until the lower end
the connecting rod in a press, and press out
of the desired connecting rod is accessible.
the bushing.
e. Remove the pairs of palnuts (23, fig.
112. Cleaning and Inspection of
33) from the connecting-rod bolts (31). Loos-
en the cap from the bolts by tapping it with a
Connecting Rod and Piston
soft-faced hammer; r e m o v e the cap of the
a. Using a wire brush, remove all carbon
from the ring grooves in the pistons and from
connecting rod (8).
the top of the pistons, making sure that the
Note. Some connecting rods are equipped with bear-
oil holes in the lower ring grooves are open.
ings.
