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Figure 16. Assembling No. 1 Connecting Rod.
(14)
Remove pushrod housing connections from ends
of cam followers, and remove cam followers from
both halves of the crankcase.
(g) Crankcase Cover Assembly.
(1)
Remove the four oil pump cover cap screws and
lift out the cover and two oil pump gears.
(2) Remove the oil pressure relief valve cap, gasket,
spring and plunger from the outside of the cover.
4. CLEANING.
(a) General.
(1)
After the engine has been disassembled, clean
the major subassemblies and miscellaneous parts in
accordance with the instructions below.
(2) The cleaning fluids prescribed herein must be of
such a type that will not attack metals - particularly
bronze and aluminum alloy parts.
(3)
After the subassemblies and miscellaneous parts
have been cleaned, thoroughly drain off excess clean-
ing fluid and dry with compressed air.
(4)
Treat steel parts with a rust preventive after they
have been cleaned and dried.
(b) Cleaning of Engine Parts - Spray the following
assemblies and parts with kerosene.
Particular
attention must be given to the special cleaning
instructions which are prescribed for each the sub-
assemblies and parts.
(1)
Crankcase - Remove the two pipe plugs from the
oil lines, clean out both halves and blowout all oil
passage tubes in both halves. Examine cam journal
22
supports for scores or deep scratches and smooth out
with crocus cloth if necessary.
(2) Cylinders - Remove acculuation of oil and dirt
from between the cooling fins. Remove carbon from
inside of cylinder head with carbon-removing com-
pound, or by soft grit or vapor grit blasting
if
equipment is available.
(3) Valve mechanism - Clean thoroughly of accu-
mulated oil, the rocker arms, rocker shaft, spring
seat, springs, retainer and intake and exhaust valves.
(4)
Oil Sump - Unscrew drain plugs and flush out the
oil sump, removing all accumulated sludge.
(5)
Crankshaft and Connecting Rods -
Clean
thoroughly with kerosene, blowing out all oil lines.
The cleaning fluid must be kept free from
grit and foreign particles.
(6)
Pistons and Piston Pins - Do not use wire
brushes or scrapers of any kind. Soft and moderately
hard carbon deposits may yield to solvent action,
which should be tried first in preference to harsher
methods.
If
the deposits remain, blast the head with
soft grit or by the vapor grit method, first having
installed tight fitting skirt protectors. Ring grooves
may
be
cleaned by pulling through them lengths of
binder twine or very narrow strips of crocus cloth.
Do not use automotive ring groove scrapers, since
the corner radii at the bottoms of the grooves must
not be altered, nor any metal removed from the
sides. Discoloration and light scoring need not be
removed from piston skirts. The use of abrasive
cloth on the skirts is not recommended, because the
diameters and contours must not be altered. Heavily
scored or burned pistons should be discarded.
(7)
Gears - Clean cam, magneto drive, generator
drive, crankshaft, starter, starter pivot and oil pump
gears, thoroughly with kerosene and dry with com-
pressed air.
5. INSPECTION.
(a) Visual Inspection. A preliminary visual inspec-
tion of all parts will indicate whether any are de-
formed, corroded, scored, galled, pitted or otherwise
damaged beyond repair. A more careful visual in-
spection should be performed on each part to deter-
mine the need for minor repair, such as stoning
thread chaSing or lapping. Due to the difficulty of
detecting cracks and if a crack is suspected in any
aluminum casting, the part should be etched. Visual
inspection should also include a detailed observation
of all areas, holes, pockets, and threads to ascertain
that all foreign material, cleaning compound and
abrasives have been removed.
(b) Etching. Before etching any area to be inspected
for cracks, all enamel, carbon and oil must be re-
moved. The surface should be clean and dry. The
following procedure and precautions apply.
(1)
Paint the area with a solution made by dis-
solving caustic soda in water (at room temperature)
in the proportions of 2lbs. of caustic soda per
gallon of water. Expose the aluminum surface
to
the cleaning action of the solution for no more than
60
seconds.
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