2-49.
CLEANING AND INSPECTION.
e. Install rupture disc (3) into cylinder cap (4), with
the red side of the disc toward the retainer end of the
cap. Place disc retainer ring (2), chamfered edge
a. Clean all parts with dry cleaning solvent,
toward the rupture disc, into the cylinder cap. Install
Federal Specification P-D-680.
disc holddown screw (1) and tighten to 60-to 90-inch-
pounds torque.
b. Inspect all parts for obvious indication of
damage such as damaged screw threads, scratched,
f. Install exhaust valve (8), valve spring (7) and
pitted, or worn finished surfaces, and broken cooling
washer (6) into the cylinder.
fins.
g. Place preformed packing (5) into the groove in
c. Inspect the cylinder bore, piston assembly,
the cylinder cap. Screw the cylinder cap into the
piston pin, connecting link and bearing for excessive
cylinder and tighten to 300 inch-pounds torque.
wear, scoring, and other damage.
h. Apply lubricating oil FSN 9150-753-4667 to the
d. Refer to table 2-1 for wear tolerances.
threads of strainer and relief valve (9), back-up ring
2-50.
REASSEMBLY.
(11), and gasket (12). Install the valve assembly into the
cylinder,
a. Place 25 needle bearings (22) around the inside
i. Install nut (10), gasket (12), back-up ring (11)
diameter of the piston pin hole in the connecting link.
into the cylinder. Install elbow (13) into the nut.
Place one washer (21) over each end of the bearings.
Carefully slide piston assembly (18), with the mark
j. Connect the intercooler assemblies (paragraph
scribed in disassembly toward the fan end of the
crankcase, over the connecting link and press piston pin
(19) through the piston, washers, bearings, and
2-51.
THIRD STAGE CYLINDER, PISTON, AND
connecting link. Secure the piston pin with cotter pin
VALVE.
(20).
2-52.
Note
a. Disconnect the intercooler assemblies at the
Assembly of the needle bearings and
third stage inlet and outlet ports (paragraph 2-40).
washers into the connecting link can be
facilitated by applying a coat of
b. Remove the fan assembly (Paragraph 2-36).
Petrolatum, VV-P-236.
c. Unscrew and remove strainer and relief valve
b. Place gasket (17) between two gaskets (16) and
assembly (23). Remove flared nut (24), back-up ring
position the gaskets onto the crankcase mounting
(25), and gasket (26).
flange.
d. Remove reducer bushing (27) and seal (28).
c. Carefully slide cylinder (14) over the piston
assembly and attach to the crankcase with nuts (15).
e. Unscrew cylinder cap (33) and remove exhaust
Tighten the nuts with equal torque.
valve (35) and valve spring (34).
d. Use a depth micrometer or dial indicator to
f. If the rupture disc (32) is defective, unscrew disc
measure piston-head-to-valve-seat clearance. Required
retainer (29 or 31) and if applicable remove disc retainer
clearance is 0.002-to 0.006-inch. If necessary, remove
ring (30). Remove rupture disc (32) from the cylinder
cylinder and add or remove cylinder-to-crankcase
cap (33).
gaskets to obtain required clearance.
Note
g. Remove nuts (37) and carefully slide cylinder
(36) over the piston assembly (40).
Overall thickness of steel gaskets can
h. Remove and discard gaskets (38 and 39).
be reduced in increments of 0.002 inch
by peeling off laminations. At least one
paper gasket must remain on each side
of steel gasket in final installation.
2-11
