Reassembly - TM-10-3930-634-340100

TM 10-3930-634-34

( 1 2 ) Refer to table 1-1 for dimensions and

(b) Insert the piston rings into the cylinder

measure the connecting rod bearings for excessive

liner, farenough inthebore to be on normal wiping

wear. Visually inspect the bearings for excessive wear

area of the ring. Measure the ring gap with a feeler

to determine if used bearings are satisfactory for

gage as illustrated in figure 3-112. Make sure the ring

further service. The upper bearings, which carry the

is parallel to the top of the liner.

load will normally show signs of distress before the

(c) If the piston ring gap is below the clearance

lower bearings do.

specified in table 1-1, file or stone the end of the

( 1 3 ) Refer to table 1-1 for dimensions an

piston ring. File or stone the ring in such a direction

measure the thickness of the bearing 900 from the

that the file or stone will cut from the outside (chrome

p a r t i n g line using a micrometer with a ball at-

plated) surface of the ring toward the inside surface.

tachment.

This will prevent chipping or peeling of the chrome

f. Reassembly.

plate. The ends of the ring must remain square and the

(1) Apply clean engine oil to the piston pin and

chamfer must be approximately 0.015 inch on the

bushing and rest the piston in a fixture as illustrated

outer edge.

in figure 3-116.

(7) Refer to table 1-1 and check the ring clearance

(2) Install one piston pin retainer in the piston as

in the piston groove as illustrated in figure 3-113.

illustrated in figure 3-116, strike the installation tool

(8) Inspect and open the holes in the spray nozzle.

just hard enough to deflect the retainer and seat it

Blow dry compressed air through the drilled oil

evenly.

passages in the rod and nozzle to make sure all

CAUTION

passages are open.

Do not drive too hard on the pin retainer or

(9) Refer to table 1-1 and inspect the connecting

the pin bushing may be moved inward and re-

rod bushings for scoring, indications of overheating or

sult in reduced pin clearance.

other damage. Bushings that have overheated may

( 3 ) Slide the piston pin into the piston and

become loose and creep together, thus blocking off

connecting rod and install the second piston pin

lubricating oil to the piston pin, bushing and spray

retainer ((2) above).

nozzle.

NOTE

(10) Replace the piston pin bushing and spray

The piston pin will slip readily into position

nozzle as follows:

without force and must float freely after in-

(a) Remove the piston pin bushing as illustrated

stallation.

in figure 3-114.

(4) Check the piston pin retainers for proper seal-

(b) Remove the spray nozzle from the connect-

ing as follows:

ing rod as illustrated in figure 3-115.

(a) Place the assembled piston and rod upside

NOTE

down on a bench and fill the piston with clean fuel oil

The orifice in the lower end of the drilled

to a level above the piston pin bosses.

passage in the connecting rod is not serviced

(b) Dry the exterior surfaces of the piston in the

separately, and it is not necessary to remove

area around the retainers and allow the fuel oil to set

it when replacing the spray nozzle.

for about 15 minutes.

(c) Install the new spray nozzle straight into the

(c) Check for seepage of fuel oil around the

counterbore in the top of the connecting rod. Support

retainers. If fuel leaks at the retainers, install new re-

the connecting rod in an arbor press. Then, place a

short 3/8 I.D. sleeve on top of the spray nozzle and

tainers. In extreme cases it may be necessary to re-

place the piston.

press the spray nozzle in the connecting rod.

(d) Empty the fuel oil from the piston and dry

(d) Clamp the upper end of the connecting rod

with compressed air. Lubricate the piston pin with

in the holder as shown in figure 3-114, so the bore of

clean engine oil.

the bushing is alined with the hole in the base of the

(5) Install the oil control rings by hand with the

installation tool.

scraping edge of each ring down as follows:

(e) Press the bushing into the connecting rod

(a) Install the expander in the upper ring groove

bore as illustrated in figure 3-114.

(fig. 3-117) being careful not to overlap the ends.

NOTE

When installing a bushing in the connecting

CAUTION

The oil control ring expander must be

rod, locate the joint of the bushing at the top

completely seated in the oil ring groove. If

of the connecting rod.

the ends of the expander should overlap, the

(f) Turn the connecting rod over in the holder

oil ring will protrude slightly and be broken

and install the opposite bushing in the same manner.

(11) Refer to table 1-1 for dimensions and ream

when the piston ring compressor is installed

the piston pin bushing.

over the piston, or when the piston and rod

3-72