Advertisement
ENGINES-8-CYLINDER
9-37
ing stamped on the engine numbering pad it indicates
that some tappet bodies are .008 inch oversize. (See
Fig. 81.)
CAUTION:
Do not disassemble a tappet on a dirty
work bench. The plunger and tappet bodies are not
interchangeable. The plunger and valve must always
be fitted to the original body. It is advisable to work
on one tappet at a time to avoid mixing of parts.
Disassembly
(Fig. 821
(1) Pry out the plunger retainer spring clip.
(2) Clean the varnish deposits from the inside of
tappet body above the plunger gap.
(3) Invert the tappet body and remove the plunger
cap, plunger, flat check valve, check valve spring,
check valve retainer and plunger spring.
(4) Separate the plunger, check valve retainer,
check valve spring. Place all parts in their respective
place in the tappet holder, Tool C-3068.
Cleaning
and Assembly
(1) Clean all tappet parts in a solvent that will re-
move all varnish and carbon.
(2) Replace the tappets that are unfit for further
service.
(3) Assemble the tappets, as shown in Figure 82.
lnspection
(1) If the tappet
or bore in cylinder block is scored,
scuffed, or shows signs of sticking, ream the bore to
the next oversize, using Tool C-3028.
(2) If plunger shows signs of scoring
or
wear and
valve is pitted,
or
if the valve seat on the end of the
plunger indicates any condition that would prevent the
valve from seating, install a new tappet assembly.
Testing
(1) Fill a pan with clean kerosene.
(2) Remove the cap from the plunger and complete-
ly submerge the tappet in an upright position.
(3) Allow the tappet to fill with kerosene, remove
the tappet, and replace the cap.
(4) Hold the tappet in an upright position and in-
sert the lower jaw of pliers, Tool C-3160, in the groove
of the tappet body (Fig. 83).
(5)
Engage the jaw of the pliers with the top of the
tappet plunger. Test the leakdown by compressing the
pliers. If plunger collapses almost instantly as pres-
sure is applied, disassemble the tappet, clean and test
again.
(6)
If the tappet still does not operate satisfactorily
after cleaning, install a new tappet assembly.
installation
(1) Lubricate the tappets.
(2) Install the tappets and push rods in their orig-
(3) Install the rocker arm and shaft assembly.
inal positions.
- m & f
KBWl
D
Fig. 83-resting
lappet Using Tool C-3160
(4) Start and operate the engine. To prevent dam-
age to valve mechanism, the engine must not be run
above fast idle until all of hydraulic tappets have filled
with oil and have become quiet. Warm up to normal
operating temperature.
TESTING THE
VALVE
TIMING
(All Engines)
(1) Turn the crankshaft until the No. 6 exhaust
valve is closing and the No. 6 intake valve is opening.
(2) For 273 and 318 cubic inch engines, turn the
NO. 1 intake valve adjusting screw in one complete
turn. (Second valve on the left bank.)
(3) For 361, 383 and 426 cubic inch engines, insert
a
?4
inch spacer between the rocker arm pad and the
stem tip of the NO. 1 intake valve (second valve on
the left bank). Allow the spring load to bleed the
tappet down giving in effect a solid tappet.
(4)
Install a dial indicator so that the plunger con-
tacts the valve spring retainer as nearly perpendicu-
lar as possible. Zero the indicator.
(5)
Turn the crankshaft clockwise (normal running
direction) until intake valve has lifted .028 inches for
273 cubic inch engine
or
.041 inches for 318 cubic
inch engine or .013 inches for 361 and 383 cubic
inch engines with 2 barrel Carburetor or .034 inch for
361, 383, and 426 cubic inch engines with 4 barrel
carburetor.
CAUTION: Do not turn crankshaft any further
clockwise
as
the valve spring might bottom and re-
sult in serious damage.
The timing on the timing indicator, located on the
chain cover, should read from 10 degrees BTDC to 2
degrees ATDC. If the reading is not within the speci-
fied limits: Inspect the timing sprocket index marks,
Hide quick links:
Advertisement
