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9-36
ENGINES-8-CYLINDER
than one tappet will be noisy. When oil level and leaks
have been corrected, the engine should be operated
at fast idle for sufficient time to allow all of the air
inside the tappets to be bled out.
Tappet Noises
(1) To determine the source of tappet noise, oper-
ate the engine at idle with the cylinder head covers
removed.
(2)
Feel each valve spring or rocker arm to detect
the noisy tappet. The noisy tappet will cause the af-
fected spring and/or rocker arm to vibrate or feel
rough in operation.
NOTE:
Worn valve guides or cocked springs are
sometimes mistaken for noisy tappets. If such is
the case, noise may be dampened by applying side
thrust on valve spring. Inspect rocker arm push rod
sockets and push rod ends for wear. If noise i s not
appreciably reduced, it can be assumed the noise is
in the tappet.
(3) Valve tappet noise ranges from a light noise to
a heavy click. A light noise is usually caused by ex-
cessive leakdown around the unit plunger, (which will
necessitate replacing tappet) or by the plunger partial-
ly sticking in the tappet body cylinder. A heavy click
is caused either by a tappet check valve not seating,
or by foreign particles becoming wedged between
the plunger and tappet body, causing plunger to stick
in the down position. This heavy click will be accom
panied by excessive clearance between the valve
stem and the rocker arm as the valve closes. In either
case, the tappet assembly should be removed for in-
spection and cleaning.
CYLINDER HEAD
ASSEMBLY
HYDRAULIC TAPPET
\
7 -
KRl69
Fig. 81-Showing
Location of External
Numbering Pad (361,383
8
426 Cubic lnchl
Removal of Tappets
(1)
Tappets can be removed without removing the
-
0
intake manifold or cylinder heads by following this
recommended procedure: Remove the cylinder head
covers.
(2)
Remove the rocker arms and shaft assembly.
(3) Remove the push rods and place them in their
respective holes in Tool C-3068.
(4)
Slide the puller Tool C-3661 through the push
rod opening in the cylinder head and seat the tool
firmly in the head of the tappet.
( 5 )
Pull the tappet out of the bore with a twisting
motion, as shown in Figure 80.
If all tappets are to be removed, remove the hy-
draulic tappets and place them in their respective
holes in tappet and push rod holder, Tool C-3068.
This will insure installation of the tappets in their
original location. If there is a diamond shaped mark-
PLUNGER RETAINER SPRING CLI P --,
NK559
W
Fig. 80-Removing
Tappet Using Tool C-3661
Fig. 82-Hydraulic
Tappet Assembly
fDisassembled V i e w )
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