Buick LeSabre 1965 Service Manual page 57

ENGINE
HEADS AND VALVES 2 - 3 5
while reconditioning t h e other
valve lifters, preparatory to test-
ing all lifters for leakdown rate.
g. Testing Lifter Leakdown
Rate
After a hydraulic lifter has been
cleaned, inspected, and assembled
it must be tested before it is
installed in an engine. Lifter Test
Fixture J-5095 has been designed
to test the leak-down rate of a
lifter to determine whether it is
within limits which assure satis-
factory lifter operation.
The following procedure must be
carefully followed to obtain an
accurate test.
1. Thoroughly clean the cup of
test fixture, install cup on fixture,
and fill it to within 1/2" of the
top with "Hydraulic Lifter Test
Fluid," which is available through
Kent - Moore Organization, Inc.
under K-M number J-5268.
2. Remove rubber washer (used
for larger lifters) and install
Gauge Sleeve J-5180-5 in the cup;
also install Buick V-8 Gauge Rod
Nose J-5180-15 in the ram.
3. Swing the weight arm up out of
the way, raise the ram and place
the valve lifter (top side up) in
Sleeve J-5180-5. The lifter must
be completely covered by the fluid
during test.
4. Lower the ram to rest in the
lifter push rod seat, then lower
the weight arm to rest on the
roller or ram as shown in Fig-
ure 2-34.
5. Operate the l i f t e r plunger
through its full travel to force
all air out of the lifter by using
a vigorous pumping action on the
weight arm. Continue the pumping
action until considerable resist-
ance is built up in the lifter and
a definite grab point is felt at the
top of the stroke, when the in-
dicator pointer is at the bottom
of the scale.
Figure 2-34—Checking Leakdown
Rate
Finally, pump vigorously for ap-
proximately 10 additional strokes
to make sure all air is removed
from the lifter. NOTE: If one
stroke offers noticeable weak re-
sistance during the last 10 pump-
ing strokes replace the check ball
in lifter and repeat the leakdown
test to this point.
6. Raise weight arm to allow the
lifter plunger to come up to its
retainer, then lower the arm to
rest on the ram roller. As the
pointer s t a r t s moving upward
start rotating the fluid cup by
turning the handle one revolution
every two seconds. See Fig-
ure 2-34.
7. Use a stop watch to check the
time required for the pointer to
move from the lower to the upper
mark on scale where marked
"BUICK V-8." The cup must be
rotated during this test.
8. The leak-down rate (time be-
tween marks) must be between
12 and 40 seconds to assure sat-
isfactory lifter performance. A
doubtful lifter should be tested
three or four times. Replace any
lifter which does not test within
the specified limits.
9. After all lifters have been
tested, place the cover over the
test fixture to keep dirt out of the
cup and fluid. The fluid should be
discarded and the cup should be
thoroughly cleaned after a few
sets of lifters have been tested.
h. Installation of Valve
Lifters
Make certain that valve lifter
guide holes and adjacent area of
cylinder block are clean, then oil
and install valve lifters. Each
lifter must slide freely in its
guide hole; if a lifter is tight in
one guide hole fit it to another
hole.
Complete the installation of all
parts by reversing the procedure
for removal. An initial adjust-
ment for clearance is not re-
quired, therefore, the valve train
does not have any provision for
adjustment after assembly.
2-15 TIMING CHAIN
COVER AND CAM-
SHAFT SERVICE
A. 401 and 425 cu. in. Engine
a. Remove and Install
Timing Chain
1. Dram engine cooling system,
then remove r a d i a t o r core,
shroud (if so equipped), fan belt,
fan and pulley, and crankshaft
balancer.
2. Remove all bolts that attach
the timing chain cover and the
water manifold to the upper and
lower crankcase and the cylinder
heads. Do not remove five bolts
attaching water pump to chain
cover. Remove cover and mani-
fold, using care to avoid damaging
lower crankcase (oil pan) gasket.
3. Remove oil s l i n g e r from
crankshaft and remove the bolt,
lockwasher and plain washer that
attaches the fuel pump operating
e c c e n t r i c and the camshaft
sprocket to front end of camshaft.