Jeep UNIVERSAL CJ-2A - Page 76

'Jeep' UNIVERSAL and 'Jeep' DISPATCHER
E
will transfer to the face of the valve. If the blue
is near the top edge of the valve face, lower the
valve seat by using the valve ·seat relief counter-
bore. If the blue is transferred to the bottom edge
of the valve face, raise the seat by using the valve
seat narrowing cutter.
When the valve seat can no longer be corrected, it
is advisable to investigate installing seat inserts.
E-62. Exhaust Valve Seat Insert Replacement
Hardened valve seat inserts for exhaust valves were
installed ih production beginning with engine serial
number 4J-200614. They will seldom require re-
placement. To avoid damaging the block, remove
an insert with a tool designed for this purpose.
When installing a new insert, make certain the
counterbore is clean and smooth. Use a driver that
w'ill keep the insert in true alignment with the bore.
Cool the insert and the installing tool with dry ice
for 30 minutes.
Note: The insert should be sufficiently cooled
to permit installation with light taps; excessive
driving of the insert may cock it in the counter bore
or crack the insert.
Make certain the valve seat is facing out. Drive
in the insert with the tool until it bottoms in the
counterbore. After installation, grind the valve
seat at an angle of 45° and then check with a dial
indicator as shown in Fig. 91.
E-63. Valve Guide Replacement
Damaged, loose, or worn valve guides must be re-
placed. Use a valve guide driver to drive out the
old guides. When replacing valve guides, maximum
engine performance can be secured only when the
guide is positioned correctly. Driver W-238 is
equipped with an adapter ring which correctly
positions the guides. See Fig. 93.
FIG. 93 -VALVE GUIDE DRIVER
Start a new exhaust valve guide, blunt (nontapered)
end first, into the valve guide bore in the top of
the cylinder block. When properly positioned, the
top end of the guide is exactly 1" [25,4 mm.] below
the level of the top of the block as shown in Fig. 94.
Start a new intake valve guide, tapered end first,
into position from the bottom of the cylinder head.
When properly positioned, the end of the guide is
just flush with the end of the valve guide bore in
the cylinder head as shown in Fig. 94.
Run a reamer (Tool C-38) through the new guides
after they have been correctly positioned.
FIG. 94-VALVE GUIDE POSITIONS
!-·Flush at this point
2-0ne Inch [25 mm.l
E-64. Tappets and Cover
The valve tappets are lubricated through oil
troughs cast in the crankcase. The troughs are
filled by oil sprayed from the connecting rod ends
and passages are drilled through the tappet guides
to carry the oil to the tappets. A groove around the
center of the tappet shank carries the oil up and
down the guide.
Check the threads and fit of the exhaust valve ad-
justing screw in the exhaust valve tappets. The fit
of a screw should be such that a wrench is required
to turn it into or out of the tappet as these are of
the self-locking type. Replace the worn part, either
the screw or the tappet, or both, if there is loose-
ness between the parts.
E-65. Crankshaft Rear Bearing Seal
Oil leakage through the rear main bearing is pre-
vented by a metal supported neoprene lip type
seal which can readily be installed without remov-
ing the crankshaft.
Should trouble be experienced with oil leaking
from the rear main bearing there are several points
which should be checked.
a. Be sure that the identifying paint daub on the
bearing cap is the same as that appearing on the
center bearing web.
b. The bearing to crankshaft clearance must not
exceed .0029" [0,0736 mm.].
c. Place sealer on the faces of the rear bearing cap
from the rear oil groove to the oil seal grooves.
d. Be sure the rubber oil seals extend about 1.["
[6 mm.] below the bottom face of the cap.
e. Be sure the oil pan gasket is not leaking.
f. Check to be sure the oil leak is not at the cam-
shaft rear bearing expansion plug or from the
crankcase.
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