Buick LeSabre 1965 Service Manual page 787

1 1 - 5 4 OPTIONAL HEATER-AIR CONDITIONER SYSTEM ACCESSORIES
SHOES—ARE USED
TO GIVE
.0005 to .0010
TOTAL CLEARANCE
THRUST UNIT
CONTROLS PISTON
HEAD CLEARANCE
THRUST UNIT CONTROLS
RUNNING CLEARANCE
.0005 to .0015
Figure 11-65—Compressor Internal
Clearances
h. Swash Plate
An a n g u l a r shaped m e m b e r
(swash plate) is located near the
center of the compressor. The
swash plate changes the rotating
action of the shaft to provide a
reciprocating driving force to
each of the three pistons. This
driving force is applied, through
the shoes and balls, to the mid-
point of each of the double end
pistons. The swash plate has two
angular faces ground smooth and
parallel to permit smooth sliding
of the shoe discs.
The plate is a press fit on to the
drive shaft and is positioned by a
Woodruff key. The swash plate
and shaft are serviced only as an
assembly.
i. Suction Pass Cover
Since the pistons are double-act-
ing, low pressure vapor from the
suction throttle valve must be
supplied to both ends of the com-
pressor and pistons.
The inlet (suction) port on the
rear head of the compressor is
connected by a hose to the outlet
side of the suction throttle valve.
A fine mesh suction screen is
located in the low pressure inlet
cavity of the rear head. Its pur-
pose is to trap any material that
could damage the compressor
mechanism. See Figure 11-66.
A flat rectangular cavity is cast
into the outer face of the front
and rear cylinders. The edges of
this cavity are machined into a
"dove-tail" shape to retain a
rectangular suction pass cover
with a neuphrene seal around its
edges. This cover and seal form
a passage for the low pressure
vapor to flow from the rear head
of the compressor to the front
head and thus supply suction re-
frigerant to the pistons and cyl-
inders at the front of the
compressor.
j. Production Type
Discharge Tube
The double-acting pistons pro-
duce a high pressure vapor at
both ends of the compressor. The
outlet (discharge) port for the
high pressure vapor is located in
the rear head of the compressor.
See Figure 11-66.
A discharge vapor tube is used
to connect the front head dis-
charge cavity to the rear head
discharge cavity. This tube has
cylindrical ends that are spun
into a hole in the front and rear
cylinder head casting to provide
a vapor tight joint. The center of
this tube has a flattened mid-
section to provide clearance be-
tween the swash plate and tube.
When the pistons in the front end
of the cylinder are on their com-
pression stroke, the high pres-
sure vapor is caused to flow into
the discharge cavity in the front
head, through the discharge
cavity. This vapor combines with
the high pressure vapor produced
by the pistons in the rear cylinder
head during their compression
stroke and flows out the compres-
sor discharge port.
k. Service Type Discharge Tube
The function and design of the
service discharge tube are the
same as that for the production
type tube with the exception of
shouldered sleeves located in both
ends of the service tube. See Fig-
ure 11-67. These shoulders pro-
vide a surface for the "O"-rings
and compression bushings. Since
the production discharge tube is
vapor sealed to the front and rear
cylinder heads by "spinning in"
the ends of the tube, equipment to
perform this "spin in" operation
during service operation would
not be economical. Therefore, if
it should be necessary to separate
the cylinder halves during a serv-
ice operation, a service type dis-
charge tube should be used when
reassembling the mechanism.
I. Pressure Relief Valve
The compressor is fitted with a
high pressure relief valve; See
SUCTION PASS COVER
FRONT HEAD
PRESSURE RELIEF
VALVE
DISCHARGE
SUCTION PORT PORT
Figure 11-66—Compressor (Rear
Cutaway View)