TM 10-4320-344-24
4.4.14 Piston and Connecting Rod Assembly Maintenance, Model 609-A. (Continued)
Table 4-7. Piston Dimensions, Model 609-A. (Continued)
Dimension
Minimum
Maximum
Width of ring groove-
0.125 inches (3.175 mm)
top-Keystone
nominal
Width of ring groove -
0.1210 inches (3.0734 mm)
0.1270 inches (3.2258 mm)
2nd
Width of ring groove -
0.1830 inches (4.6482 mm)
0.1890 inches (4.8006 mm)
o i l c o n t r ol
i .
Inspect crankshaft for any rough or scored marks that might damage bearings (3
and 13). If any rough marks are found, polish shaft with emery cloth.
Thoroughly clean shaft after polishing.
All parts should be measured at room temperature; otherwise, dimensional
tolerances during piston and ring fitting may be incorrect.
j .
Measure size of cylinder bores.
k.
l .
m.
.
Piston size is identified by letter stamped on top of piston.
.
If new standard piston is installed, make sure size letter stamped
on top of piston-agrees with bore size letter stamped on cylinder
b l o c k.
Check fit of piston (10) without piston rings (4, 5, 6, and 7) in cylinder
bore. If any binding occurs, remove piston (10) and check for burrs on piston
(10) and cylinder wall.
Insert new piston rings (4, 5, 6, and 7) one at a time inside cylinder bore.
Ensure each piston ring (4, 5, 6, and 7) is at bottom of piston ring (4, 5, 6,
and 7) travel.
Using a piston (10), push piston ring (4, 5, 6, and 7) down so it is parallel
with top of cylinder bore.
All ring gaps should be between 0.0100 inches (0.2540 mm) and 0.0200 inches
(0.5080 mm).
n.
Measure gap in piston ring (4, 5, 6, and 7). After checking clearance, remove
piston rings (4, 5, 6, and 7).
o .
Inspect piston rings (4, 5, 6, and 7) for the clearances listed in Table 4-8.
4-46
NOTE
NOTE
