TM 5-3810-295-34
e. Replacement of Crosshead Guides. Remove
has been resurfaced, it will be necessary to cut grooves
in the cylinder head over each cylinder liner sealing
crosshead guides with a suitable dowel puller. Press
area. These grooves will assure a better seal between
new guides into head until a 1.86- to 1.88-inch protru-
the cylinder head gasket and block. Groove shall be cut
sion is obtained.
f. Valve Seat Insert. When a seat is worn beyond
to a depth of 0.006-0.008 inch.
d. Replacement of Valve Guides. Valve guides
regrind specifications, a new valve seat insert shall be
shall be replaced as follows:
installed as follows:
(1) Worn out valve guides shall be driven out
WARNING
from the underside of the cylinder head.
Cover the valve seat with a shop rag to avoid
(2) Press guides into head to obtain a 1.315- to
injury from broken pieces of the seat.
1.325-inch protrusion above head surface.
(1) Remove loose or excessively worn valve
CAUTION
seat insets by striking insert sharply with a chisel,
Guides which have been through the "tuff-
causing it to crack and release the press fit. Remove all
triding" process, identified by a dull gray ap-
inserts if head has been resurfaced.
pearance, are not to be reamed.
(2) Enlarge counterbore to next oversize.
(3) Insert valve into valve guide and check for
Inserts are available in standard and oversize shown in
freedom of movement. If valve does not move freely,
table 14-2. If head has resurfaced, and standard inserts
ream valve guide from bottom side of cylinder head
are to be used, deepen counterbore only.
with proper reamer to dimensions 0.4525-0.4532 inch.
Table 14-2 Valve seat insert specification
Insert
Oversie
Insert
Cylinder head
Insert
part No.
Diameter
depth
OD
ID
thickness
127930
STD
STD
2.0025/2.0035
1.9995/2.0005
0.278/0.282
127935
0.010
STD
2.0075/2.0085
2.0045/2.0055
0.278/0.282
127931
0.010
STD
1.0125/2.0135
2.0095/2.0105
0.278/0.282
127932
0.020
0.005
2.0225/2.0235
2.0195/2 0205
0.283/0.287
127933
0.030
0.010
2.0325/2.0335
2.0295/2.0305
0.288/0.292
127934
0.040
0.015
2.0425/2.0435
2.0395/2.0403
0.293/0.297
NOTE: Dimensions are in inches.
(3) Cut counterbore 0.006-0.010 inch deeper
Do not rotate valve. This procedure will indicate the area
than insert thickness to permit peening of heat to hold
of contact on the valve face. The most desirable area of
insert. Surface at the bottom of counterbore must be
contact is at the center of the valve face.
h. Testing of Valve Springs. Test valve springs on
perfectly flat for the insert to seat properly. Remove all
chips and dirt.
a spring tester that is capable of accurate measurements
(4) Install valve seat insert, and with a one-
of spring lengths.
fourth inch diameter round end punch, peen around
(1) Spacers may be used under valve spring,
insert at least four or five places.
when insert and valve have been refaced to make valve
spring check within load limit. A maximum of one-six-
CAUTION
teenth of an inch spacers may be used when head has
Over-swaging around insert may crack
been resurfaced and valve and seat have been refaced.
cylinder head.
(2) If valve spring compresses to 1.724 inches
g. Grinding of Valve Seats. If an old insert is to be
with less than 145 pounds, it should be discarded.
refaced, or if a new insert is installed, the work must be
i. Injector Sleeve. Worn injector sleeves must be
done with a grinding wheel using the eccentric method.
(1) Apply a 30ƒ grinding wheel on the valve
replaced.
(1) Using a " muffler cutting tool" remove
insert.
injector sleeves.
(2) If seating area (2, fig. 14-14) is wider than
CAUTION
one-eighth of an inch, stock can be removed from point
Extreme caution should be taken not to
"A" with a 15 grinding wheel.
damage the head surfaces.
(3) Check concentricity of each valve seat
(2) Remove all foreign material from injector
insert relative to the valve guide with a dial indicator. If
sleeve sealing area.
runout exceeds 0.002 inch, check for bent valve guide
(3) If head was resurfaced, restore shallow
before regrinding the insert.
recess area (1, fig. 14-17) around injector port. With a 3-
(4) Apply a light coat of Prussian Blue to the
inch grinding stone dressed to 7ƒ angle (2), grind area
valve seat insert. Lower the stem of the valve in the
valve guide until the valve mates with the valve seat.
(1) to
14-16
