The piston and pin (1) are matched and
are not replaced separately. Replace as
an assembly only. The three ring
assemblies (2) each consisting of an
outer ring and an inner ring (3) are
supplied in the form of a piston ring kit
and should be replaced as a kit set.
Remove four cap screws (5) and lock
washers (6); remove cylinder head (4),
head gasket (7), valve assembly (8) and
valve gasket (15) from cylinder (16).
To disassemble valve assembly (8),
remove cotter pin (10), castle nut and
separate upper guard from valve seat.
The lentoid springs (11), valve ring (12),
lentoid springs (13), valve ring (14), and
cotter pin (10) are supplied in the form of
valve repair kit and shall be replaced as
Remove lentoid springs (11), valve ring
(12), separate and remove lower guard,
remove lentoid springs (13), and valve ring
(14) from valve seat.
The center bolt is secured in valve seat
with dowel pin peened over and neither
should be removed.
Cleaning. Refer to paragraph 6-3.a for general
Remove caked grease or dirt with a non-
metallic brush after immersing part in
solvent. Scrape carbon, and old gasket
material from affected surfaces.
Clean parts with care. Do not mar or
scratch contact or seating surfaces.
Exhaust valve components should not be
Inspection. Refer to paragraph 6-3.b for general
Parts with dimensions listed in Table 6-1,
Table of Limits, shall be measured to
ascertain acceptability for repair or
replacement and assembly.
Repair or Replacement. Refer to paragraph 6-
3.c for general repair or replacement instructions.
Replace all gaskets removed during
Do not remove any more material than is
necessary to completely remove the
glaze. Clean the cylinders in
accordance with CLEANING
Remove glaze from cylinder walls with
portable cylinder hone (using 280 to 400
grit stones). a glaze buffer, or a crocus
cloth, depending on condition of cylinder
Assembly. To assemble the third stage cylinder
and piston group, proceed as follows:
A repair kit consisting of lentoid springs (
I I ) valve ring (12), lentoid springs (13),
valve ring (14), and cotter pin (10) is
available. At overhaul replace these
parts as a set. Assemble lentoid springs
(11 and 13) as illustrated in Figure 6-8.
At overhaul of intake-exhaust valve
assembly (8), use available repair kit (9).
Assemble valve ring (14) and lentoid
springs (13) in valve seat and assemble
lower guard plate. Assemble valve ring
(12), lentoid springs (11), upper guard and
castle nut. Secure nut on center bolt with
cotter pin (10).
Assemble valve gasket (15), valve
assembly (8). head gasket (7), and
cylinder heat (4) to cylinder (16). Secure
head to cylinder with lock washers (6) and
cap screws (5). Torque cap screws (5) to
45 pounds foot (Table 6-2).
The piston ring assemblies (2) are
available in a ring kit and are to be
replaced as a set.
Assemble inner and outer rings of ring
assemblies (3) in grooves on piston (1).
Coat the rings with clean compressor oil to
aid in assembly.
Fourth Stage Head and Cylinder Group (See
Figure 8-17). The following paragraphs contain
disassembly, cleaning, inspection, repair or
replacement, and assembly instructions for the fourth
stage head and cylinder group.