Piston, Rings, Connecting Rod, and Cylinder liner

TM 10-3930-242-34

Figure 3-50. Pistons, connecting rods, oil pump screen, and

inlet pipe, removal and installation.

CAUTION

(3) Refer to lubrication order and service

e n g i n e l u b r i c a t i o n system.

W h e n removing or installing piston

r i n g s , do not spread rings more than

Piston, Rings, Connecting Rod, and Cy-

3-26.

necessary to avoid overstressing the

linder liner

rings.

a. General. The pistons are cooled by fresh air

NOTE

from the blower to top of piston in the combus-

Punch a hole through center of a piston pin re-

tainer with a narrow chisel or punch and pry the

t i o n chamber and by the water jacket around

retainer from piston, being careful not to damage

cylinder. Also, piston is cooled by a spray of lub-

piston or bushings. Remove and disassemble the

ricating oil directed at underside of piston from

pistons, rings, connecting rod, and cylinder liner

a nozzle in top of connecting rods on all engines

in numerical sequence (fig. 3-51).

equipped with an oil cooler. The piston rings

d. Cleaning and Inspection.

maintain uniform compression pressures in all

(1) Piston and rings.

c y l i n d e r s . The cylinder liner houses the piston.

(a) Clean all parts thoroughly with fuel oil

and dry with compressed air. If fuel oil will not

b. Removal,

remove carbon deposits, use P-D-680 solvent, or

(1) Drain engine oil and remove oil pan

e q u a l , that will not attack the bushings or tin

(para 3-24).

p l a t i n g on the piston. The piston ring grooves

(2) Remove cylinder head (para 3-19).

m a y be cleaned with a suitable tool, such as a

(3) Refer to figure 3-50 and remove the pis-

broken half of a compression ring that has been

t o n s arid connecting rods,

s h a r p e n e d to a bevel edge.

(a) Remove carbon from the upper sur-

(b) The cooling surfaces on the inside of

face of cylinder liner,

t h e piston should also be cleaned. Oil return

(b) Remove ridge from the liner at top of

h o l e s in the piston skirt must be thoroughly

r i n g travel, if present.

c l e a n e d . Care must be exercised so that holes

are not enlarged during the cleaning process.

c. Disassembly.

3-59