TM 5-4310-393-14
e.
Measure piston compression ring groove width
(Figure 543, Item 1). Measurement should be 0 0828 to 0 0843 inch
(2.100 to 2.143 mm). If measurement is greater than 0.843 in (2.143
mm), replace piston.
f.
Measure
piston
ring
groove
(2)
width.
Measurement should be 0.0811 to 0 0908 inch (2.060 to 2 310 mm). If
measurement is greater than 0 0908 in (2 310 mm), replace piston.
g.
Measure
oil
control
ring
groove
(3)
width.
Measurement should be 0.1582 to 0.1599 inch (4 020 to 4 060 mm). If
measurement is greater than 0 1599 in (4.060 mm), replace piston
WARNING
DRY CLEANING SOLVENT P-D-680 (SAFETY OR
STODDARD'S
SOLVENT)
IS
POTENTIALLY
DANGEROUS.
AVOID
REPEATED
AND
PROLONGED BREATHING OF VAPORS AND SKIN
CONTACT WITH LIQUID. DO NOT USE NEAR OPEN
FLAME, ARCING EQUIPMENT, OR OTHER IGNITION
SOURCES. ALWAYS WEAR EYE PROTECTION
AND PROTECTIVE CLOTHING. THE FLASH POINT
OF P-D-680 IS 100 TO 138 DEGREES F (38 TO 59
DEGREES C).
FIGURE 5-42. MEASURE PISTON
WARNING
DEATH OR SERIOUS INJURY COULD OCCUR IF COMPRESSED AIR IS DIRECTED
AGAINST THE SKIN. DO NOT USE COMPRESSED AIR FOR CLEANING OR
DRYING UNLESS THE PRESSURE HAS BEEN REDUCED TO 30 PSI (2.06 BAR) OR
LESS. WHEN WORKING WITH COMPRESSED AIR ALWAYS USE CHIP GUARDS,
EYE PROTECTION, AND OTHER PERSONAL EQUIPMENT.
h.
If any groove width measurements are smaller than the minimum values given above, piston ring
grooves may be clogged with carbon deposits. Clean piston with dry cleaning solvent. Dry with low pressure compressed
air. Take measurements again.
i.
Inspect wrist pin for scoring, fretting, pitting, or Indications of overheating. If severely damaged,
replace wrist pin.
B.
Repair.
1.
Making Minor Repairs.
a.
Remove slight scoring, or fretting on piston.
Clean and repeat procedure If necessary. Refer to Table 5-3 for
dimensions, tolerances, and wear limits of parts.
C.
Replace.
1.
Replacing/Reinstalling the Piston.
FIGURE 5-43. PISTON RING GROOVES
a.
If the cylinder has been replaced, the piston must also be replaced.
5-34
