Jeep UNIVERSAL CJ-2A - Page 74

'Jeep' UNIVERSAL and 'Jeep' DISPATCHER
E
E-59. Inspection of Valves, Springs,
and Guides
Clean the valves on a wire wheel, making sure that
all carbon is removed from the top and the under-
side of the heads and that all gum and varnish
deposits are removed from the stems.
Polish the valve stems with steel wool or crocus
cloth. Visually inspect all valves for warpage,
cracks, or excessive burning and discard if one of
these conditions exists. Replace any worn, pitted,
or corroded valves that cannot be cleaned with a
wire
brush. Replace any valves when seats are
pitted, burned, or corroded so badly that they
cannot be cleaned up with a light refacing on .a
valve refacing machine.
Replace valves with marks of scoring or abrasion
visible on the stem. Replace any valves with bent
stems which will be apparent when the valve is
FIG. 89-TESTING VALVE SPRING
1-Torque Wrench
2-Spring Testing Fixture
3-Valve Spring
mounted in the valve refacing machine.
Note: Use only hard-face exhaust valves, Part
No. 928342, for replacement.
Examine the stems of valves which employ the
ball bearing rotators. Wear marks around the cir-
cumference of the stems indicates that the valve is
rotating satisfactorily. Vertical heavy pressure
areas indicate that the valve is not rotating and the
valve spring retainer (Roto Cap) should be replaced
if at fault. Check the diameter of the valve stem
at two or three places along the length of the stem
with a micrometer. The intake valve stem diameter
is .3733" to .3738" [9,482 a 9,49S mm.]. The
exhaust valve stem diameter is .371" to .37Z"
[9,423 a 9,449 mm.].
FIG. 90-VALVE WITH ROTO CAP
Note: Exhaust and intake valve springs are
similar in appearance. They must not be inter-
changed as they have different spring charac-
teristics.
Wash the valve springs thoroughly in solvent.
Visually examine the springs and replace any that
are deformed or obviously damaged. Examine for
corrosion from moisture or acid etching which might
develop into surface cracks and cause failure.
Measure the over all free length of the springs and
replace any that do not measure to standard:
13!1
2
" [3S,7 mm.] for intake valve springs and 272"
[63,S mm.] for exhaust valve springs. If possible,
check each valve spring in a valve spring testing
fixture as shown in Fig. 89. Test each spring when
compressed to the two different spring lengths
given (representing valve closed and valve open
spring length). If any spring fails to register spring
tension equal to or greater than the minimum load
limit in pounds specified for that spring length,
replace the spring.
Length
Intake valve spring ..... 1.66" [43,5 mm.]
1.40" [35,6 mm.]
Exhaust valve spring ... 2.11" [53,6 mm.]
1.75' [44,5 mm.]
Minimum Load
66 lb. [29,9 kg.]
140 lb. [63,5 kg.]
47 lb. [21,3 kg.]
110 lb. [49,9 kg.]
Note: When using a spring checking fixture as
shown in Fig. 89, it is necessary to convert the
torque wrench reading which is in pounds-feet to
the static pound pressure specified above accordi.ng
to the instructions furnished with the wrench. For
example, should the torque wrench reading be
SO lb-ft. and the wrench is two feet long the static
pressure of the spring will be SO x 2 or 100 lbs.
Clean the valve guides with a standard valve guide
cleaner or a wire brush. Check the. valve guides in
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