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Referring
to t.lie
diagram,
above. the
coolant is
set
in
forced recirculation by
the water
pump.
which
is
a
centrifugal
pump
driven by cooling-fan belt.
The pump
draws
coolant from
the lower
tank section of
ra
diator
(4) and forwards
it to the
water inlet
of crankcase (7).
Upon entering the middle
section
of
the
crankcase
,
coolant flows
in
the
jac:k-et
to
cool the
cylinders:
lhen
it
rises
into
jacket
(5)
of cylinder
head
(6)
to
cool the
combustion
chambers and areas around
the
intake and
exhaust valves
.
From the
forward end of
the cylinder
head.
the
coolant
I
now hot because
it
has
taken
as
much
heat"
it
can, flows into
th
e
inlet of
thermo,ta
t (1).
The thcnnos-tat
,
responding
to coolant
temperature,
controls
the
now
of
coolant toward
the
radia
tor
upper
tank.
When
coolant
temperatwe
is
low
as
when the
enginl! has
just been started
up
from
cold
state,
the
thermostat valve
remains
closed
and aU
of the
coolant
is
diverted back to
the
water
pump
inlet through bypass
hose (3)
:
under
this
condition, radJ.tor (4)
is
bypassed
by
the
c:oolnnt.
As
the
nsing
coolant temperature reaches 76.S
o
C
(I69.7'F),
the
thermostat
valve
begins to open increas-
ingl)' wide
and
the
coolant
begins to now
to
radiator
(4)
@
CONSTRUCTION
AND FUNCTION
at
a rising
rate
of
flow,
whh
a corresponding
decreases
in
the
amount
of
coolant
being
byp
....
d. As the tern·
pe raturo reaches
90'C
(194'F),
the
,'alve
becomes full
open
,
shutting offth. bYpass
passage.
The
probe for
temperature gauge (2)
is
installed
in
the
cooiant outlet of cylinder head
.
It is
with
the sign
oj
produced by this probe that
the
gauge Oocated
at the
control station)
operates.
Water
pump
Pump cas.
(6)
is
secure
d
to
cylinder block
through
cover
plate
(10).
Pump
shaft
(3)
is
StJpported
by
two
ball
bearings
(5)
having
a large
bearing
capacity.
Lu
be
aU is
supplied
under pressure
from
engine main
oil
gallery
into
space
(I)
fanned around
shaft
between the
two
bearings.
Two
oil
se
als (2) contain
the
oil so admitted to lubricate
the
bali
bearings.
Unit seal (9) prevents coolant
from
leaking out
along the shaft. Impeller
(8)
is threadedly
mounted
on
the
inner end
of Ihc shall, and
puUey (1)
is
keyed lo the
outer
end_
Crankshaft
pulley and pump pulley (1)
are
10
the speed
ratio of
1
to 1.2
.
Th.
pump capacity Is 100 lilers
(6103 co
in
.)/minute
at 2520 pump rpm_
l·Pu_
" e V
2-011 $EliI!Il
J..Shah
4.spacer
5-BBII
be.
a rings
6-Caso
7-$pace
filled with lube
0
1'
S.lmpl!llIer
g..Unit
91!lsl
,O-Co\,or
pl
ate
Water pump
-
Cross se
ction
Thenoostat
The
thermostat!,
of
wax type
,
designed to
,tart
opening
ilS
valve at
765
±
Z'C
(169 .7 ±
3.6·F)
of
ri'ing
tem-
'
perature and
open it
fully at
90'C
(J94'F),
lifting
il
off
the seat
by 9
mm
(0.35
in.)
(ma.UmUTO lift).
-v~~
Lift: g-mm
~(],3S
in.)
37
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