TM 5-3895-360-13
6-3. ENGINE CRANKSHAFT PISTON, AND CONNECTING ROD REPLACEMENT (Con’t).
CLEANING AND INSPECTION
WARNING
a.
b.
Dry cleaning solvent, P-D-680, Is toxic and
flammable. Always wear protective goggles
and gloves, and use only In a well-ventilated
area. Avoid contact with skin, eyes, and
clothes, and DO NOT breathe vapors. DO
NOT use near open flame or excessive heat.
The solvent’s flash point is 100°F-138°F
(38 °C-590C). If you become dizzy while us-
ing cleaning solvent, immediately get fresh
air and medical help. If solvent contacts
eyes, Immediately wash your eyes and get
medical aid.
Compressed air used for cleaning or drying
purposes, or for clearing restrictions, should
never exceed 30 psi (207 kPa). Wear protec-
tive clothing (goggles/shield, gloves, etc.)
and use caution to avoid injury to personnel.
Clean parts with dry cleaning solvent (Item 16, Ap-
pendix E) and dry with compressed air.
Using honing unit, clean carbon from exhaust ports
and exhaust passages.
WARNING
Carburetor cleaning compound is a corrosive
Iiquid. If splashed in eyes, it can cause blind-
ness. If splashed on skin, It can cause serious
burns. Always wear protective goggles or
lenses, rubber apron, and rubber gloves. if ac-
cidently splashed in eyes or on skin, flush with
clean, cool water. Refer to FM21-11 for first aid
information and seek medical attention imme-
diately.
c.
d.
e.
f.
g.
Soak piston in carburetor cleaning compound
(item 6, Appendix E). Using flexible carbon scraper,
scrape piston head clean and rise with water.
Using flexible carbon scraper and wire brush (Item 4,
Appendix E), clean piston ring grooves.
Inspect piston for cracks, scoring, and excessive
wear or scorching. Replace piston if badly scored
below top ring groove.
NOTE
Refer to Figure 6-13, Measuring Piston Ring
Grooves, for step f.
Using feeler gage, measure piston ring grooves (20).
Measurement must be 0.065-0.067 in. (1.65-
1.70 mm). Replace piston if measurement is not
within specification.
Figure 6-13. Measuring Piston Ring Grooves.
Inspect piston pin for cracks, bends, and breaks.
Using outside caliper micrometer, measure outside
diameter. Outside diameter must be 0.50000-
0.50015 in. (12.70000-12.70381 mm). Replace pis-
ton pin if measurement is not within specification,
6-11
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