TM 5-4310-349-14
Table 5-2. Compressor Repair And Replacement Standards (Continued)
Desired clearance
Maximum
Manufacturer's
allowable wear
dimensions and
and clearance
tolerances in
inches
Min.
Max.
Min.
Max.
Out-of-round..........
......................
........................
............................. .........................................0...............................
. 005
End play ...................
......................
........................
0.000
0.002
Pistons and Pins
Piston, low-pressure -
4.619
4.620
0.003
0.005
0.005
Piston, high-pressure -
2.4965
2.4975
0.0015
0.0035
0.003
Pin, low-pressure
2.125
2.135
0.0001
0.0005
Pin, high-pressure
2.125
2,135
0.0001
0.0005
Bearings, Connecting Rod
Bearing, I. D
.8125
.8130
0.001
0.007
Bearing, side clearance
0.010
0.017
(3) Measure the clearance of the piston pin to the
5-4.
Pistons, Piston Rings, Connecting Rods, and
piston pin bushing. Check for proper fit. Aline or replace
Cylinder Block (Model HR10-8M-1 and Model 20-277M)
connecting rods if necessary.
a. Removal and Disassembly.
(4) Place the piston rings in the cylinder bore with
(1) Remove the compressor assembly.
the piston ring square in the cylinder bore about 1/2 inch
(2) Refer to figure 5-1 and disassemble tube
from the top.
assemblies, cooler tubes, manifolds, and air cleaner as
(5) If the ring gap is less than the specified width,
shown.
file across butt ends of the rings to increase the gap to
(3) Refer to figure 5-2 and disassemble intake and
the required tolerance. If the ring gap is greater than
exhaust valves as shown.
required, replace the entire set of rings.
(4) Refer to figure 5-3 and remove handhole plate.
(6) Measure the ring groove in the piston for
(5) Refer to figure 5-3 and remove connecting rod
wear. Replace piston if necessary.
bearing caps.
c. Reassembly and Installation.
CAUTION
(1) Refer to figures 5-1, 5-2, and 5-3 and
Mark the connecting rod from which
reassemble and install the pistons, piston rings,
connecting rods, and cylinder block, taking the following
the
caps
were
removed,
and
precautions:
reassemble caps on the same rod. Do
not intermix the connecting rods and
(a) If new connecting rod bushings are to
caps.
be installed and are not prefitted, ream the bushings.
(6) Disassemble cylinder block from crankcase as
(b) When installing piston rings expand
shown in figure 5-1.
them carefully and sufficiently to allow the ring to slide
freely over the piston to the proper position. Starting with
(7) Disassemble connecting rods, pistons and
the bottom ring, install piston rings in their proper
rings as shown in figure 5-3.
grooves. Stagger ring gaps so that they are not lined up.
NOTE
(c) Lubricate each piston and connecting
Mark connecting rod and piston to assure
rod assembly with a light coat of engine oil before
correct relationship at reassembly.
installing in cylinder block. Compress the piston rings
NOTE
carefully when installing in cylinder.
Do not remove the connecting rod bushings
(d) When installing cylinder block to
unless inspection reveals them defective.
to 45 ft.-lbs. torque.
b. Cleaning, Inspection and Repair.
(e) Torque connecting rods nuts to 25 ft.-
(1) Clean all parts with cleaning solvent and dry
lbs. torque.
thoroughly.
(f) When reassembling intake and
(2) Inspect the cylinder block for broken cooling
exhaust valves be sure to seat large diameter of the
fins and cracks. Inspect the cylinder bore for wear,
spring in the cage of all valves.
scoring, pitting, or other damage. Replace the block if
defective.
Change 2 5-4
