TM 9-6115-1604-34
NAVFAC P-8-633-34
(8)
Turn the crankshaft (32) to TDC, and remove the piston (10) and connecting rod (4) as an assembly.
(9)
Replace the cap (3) on the connecting rod (4), and temporarily install the bolts (1) and washers (2) hand-tight to
retain the bearing shells (11).
(10)
Remove the other piston and connecting rod assemblies following steps (3) through (9), above.
c. Disassemble.
NOTE
Before disassembly, match-mark the piston and connecting rod so that they can be
reassembled in the same positions from which they were removed.
(1)
Using a 0.006 inch (0.15 mm) feeler gage, check the top, and intermediate piston ring to piston land side groove
clearance. If the gage enters freely, either the piston or piston ring is worm. Inspect the piston and piston rings
in accordance with step e, below.
CAUTION
Over-expanding a piston ring during removal or Installation will distort the ring and cause ring
failure. Do not expand the rings more than necessary during removal or Installation .
(2)
Using piston ring expander ST-1269, remove the top compression ring (5, Figure 9-24), intermediate
compression ring (6), and oil control ring (7).
CAUTION
To avoid damage to the piston, do not drive, press, or otherwise force the piston pin from the
piston. Remove the piston pin using thumb pressure only. If the piston pin Is difficult to
remove, heat the piston in hot water, or heat for 15 minutes In an oven set to a maximum of
210°F (99°C).
(3)
Remove the snap rings (8) and using thumb pressure only, remove piston pin (9) and piston (10) from the
connecting rod (4). Discard the snap rings (8).
(4)
Remove the temporarily installed bolts (1) and washers (2), and remove the cap (3) and connecting rod bearing
shells (11). Mark the bearings rings relative to top and bottom location, rod number, and bank using a felt tip
pen.
d. Cleaning.
WARNING
Dry cleaning solvent PD-680, Type III, or equivalent, Is flammable and moderately toxic to the
skin, eyes, and respiratory tract. Assure adequate ventilation. Skin, eye, and respiratory
protection Is required to avoid Injury to personnel.
(1)
Clean all parts thoroughly using dry cleaning solvent PD-680, Type III, or equivalent, to remove all traces of built-
up varnish.
(2)
Clean heavy carbon deposits from the top of the pistons using carbon scrapers. Be careful not to gouge the
aluminum surface.
(3)
Clean all carbon deposits from the ring grooves using a ring groove cleaner, or sections of old piston rings that
have been ground to a bevel. Be careful to remove the carbon only. Do not gouge or remove metal from the
ring grooves.
(4)
Clean the oil drain-back holes in the oil control ring groove using a drill just large enough to remove the carbon.
Turn the drill by hand being careful to remove the carbon only.
9-48
