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106
ENGINE AND ENGINE REBUILDING
ment of the valve stem from side to side
(crosswise to the head) will cause a direct
movement of the indicator stem. The in-
dicator stem must contact the side of the
valve stem just above the valve guide.
c. Drop the valve head about Vie in. off
the valve seat.
d. Move the stem of the valve from side
to side using light pressure to obtain a
clearance reading. If clearance exceeds
specifications, it will be necessary to ream
valve guides for oversize valves.
NOTE: See "Valve Guide and Seat Ser
vice" for detailed overhaul procedures.
12. Check valve spring tension with a suit
able spring tester. Springs should be com
pressed to the specified height and checked
against the specifications chart. Springs should
be replaced if not within 10 Ibs. (44N) of the
specified load (without dampers).
13. Inspect rocker arm studs for wear or
damage.
14. Check the cylinder head for warpage
with a straightedge. If warpage exceeds .003
in. in a 6 in. span, or .006 in. over the total
length, the cylinder head must be resurfaced
(which is akin to planing a piece of wood).
Resurfacing can be performed at most ma
chine shops.
NOTE: When resurfacing the cylinder
heads(s) ofV8 engines, the intake manifold
Measuring valve spring installed height
1 & 3 CHECK DIAGONALLY
2 CHECK ACROSS CENTER
Checking, cylinder head for warpage—typical
SEE SPECIFICATIONS
mounting position is altered, and must be
corrected by machining a proportionate
amount from the intake manifold flange.
15. Insert a valve in the proper port.
16. Assemble the valve spring and related
parts as follows:
a. Set the valve spring shim, valve
spring, damper assembly, oil shedder and
valve cap or rotator in place.
b. Compress the spring with Tool J-8062,
or equivalent.
c. Install oil seal in the lower groove of
the stem, making sure that the seal is flat
and not twisted.
d. Install the valve and release the com
pressor tool making sure that the valve
stems seat properly in the upper groove of
the valve stem. Grease may be used to hold
the locks in place while releasing the com
pressor tool.
17. Install the remaining valves, repeating
assembly sequence.
18. Check each valve stem oil seal by plac
ing a Leak Detector Tool J-23994, or equiva
lent, over the end of the valve stem and against
the cap (or rotator). Operate the vacuum pump
and make sure no air leaks past the seal.
19. Check the installed height of the valve
springs, using a narrow thin scale. A cutaway
scale will help. Measure from the top of the
shim or the spring seat to the top of the oil
shedder. If this is found to exceed the speci
fied height, install a valve spring seat shim
approximately Vie in. (1.6mm) thick. At no
time should the spring be shimmed to give
an installed height under the minimum spec
ified.
Checking valve stem oil seals with vacuum tester
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