TM 10-4610-310-14
0121 00
REMOVAL continued
3. Remove the piston (2) from the engine block (4).
4. Remove the upper (3) and lower (5) journal bearings only if necessary.
5. Remove the piston rings (1) if necessary.
INSPECTION
1. Check and measure the piston outside diameter as follows:
a. Replace the piston if the outer surface and ring grooves are damaged excessively.
b. Measure the piston outside diameter across the piston pin approximately 12 mm (0.47 inch) from the
bottom end of the piston. Replace if less than 2.746 inch (69.70 mm). See Figure 2.
Figure 2. Piston Outside Dimension Measurement.
CHECKING PISTON PINHOLE
Perform the following check of the piston pinhole:
1. Replace the piston if the pinhole is damaged.
2. Measure the inside diameter of the piston pinhole. Replace the piston if hole diameter is more than
3. If the inside diameter exceeds the service limit of 19.07 mm (0.75 inch), replace the piston.
PISTON RINGS
Measure the piston rings as follows:
1. Measure the thickness (t) and height (h) of the piston ring. See Figure 3.
ST
1
RING
h
BARREL FACE
T
ND
2
RING
TAPERED FACE
RD
3
RING
COIL EXPANDER FACE
Figure 3. Piston Rings Measurement.
