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PART 1-1
-ENGINE
15
CYLINDER
HEAD
BOLT
BORE
FROM NO. 2
CAMSHAFT
BEARING
TO
LEFT
CYLINDER
HEAD,
AND
FROM NO.
4
CAMSHAFT
BEARING
TO RIGHT
CYLINDER
HEAD,
NO. 2
SUPPORT,
LEFT HEAD
NO. 4
SUPPORT,
RIGHT HEAD
A1247-A
FIG.
9-Valve
Rocker Arm Shaft
Lubrication
of
the
cylinder
head
and
in
the
push
rod chamber
floor.
CRANKCASE VENTILATION
The
engine
has
either a vent
tube-
type
crankcase
ventilation system or
a
positive
crankcase ventilation
sys
tem.
VENT TUBE-TYPE CRANKCASE
VENTILATION SYSTEM
A
crankcase ventilation
tube
is lo
cated at
the
rear of
the
engine.
The
forward
motion
of
the
car
causes
a
partial vacuum
to
be formed
at
the
tube
outlet.
This
vacuum
action
causes
air
to
be
drawn
through the
engine
from
the
oil
filler cap located
at
the
front
of
the
intake
manifold
(Fig.
10). The filler cap
contains
a
filtering
element which
filters
the
in
coming
air.
From
the
filler
cap,
the
air
flows
into
the
front
section
of
the
valve
FROM
CRANKCASE
OUTLET
LOW INTAKE
MANIFOLD VACUUM
TO
INTAKE
MANIFOLD
HIGH INTAKE
MANIFOLD VACUUM
V\/\A/s
HIGH SPEED
OPERATIONS
LOW SPEED
OPERATIONS
FROM
CRANKCASE
OUTLET
A1458-B
FIG. 11
Positive
Crankcase Ventilation Regulator Valve
push
rod
chamber
where
there
are
few contaminating
vapors.
Here,
the
incoming
air
has
a
chance
to
warm
up
before contacting contaminating
vapors
originating
in
the
crankcase.
Warm ventilating
air
minimizes
the
formation
of
crankcase
sludge.
The ventilating
air
is directed
by
a
baffle,
located
on
the
underside
of
the
intake
manifold,
upward
into
the
front
of
both
valve rocker
arm
chambers.
The baffle
also
directs
air
to the
front
of
the
lower
crankcase
and
into
the
timing
chain chamber.
Air from
the
valve
rocker
arm
chamber
and
from
the
crankcase
flows into
the
rear of
the
valve
push
rod
chamber.
All
air
is
then
directed
out
the
crankcase ventilation
tube.
VENT-TUBE VENTILATION
POSITIVE
CRANKCASE
VENTILATION
SYSTEM
Ventilating
air enters
the
engine
in
the
normal
manner
through
the
breather
cap
and
is
distributed
through the
engine
in
the
same man
ner as
in
the
vent
tube-type
system.
However,
instead
of
the
ventilating
air
being
discharged
to the
atmos
phere,
it is directed into
the
intake
manifold
thru the
carburetor spacer.
The
air
is directed into
the
intake
manifold
through
an
exhaust
tube
which
extends
from
the
crankcase
ventilation
outlet
to
a
spring-loaded
regulator valve and
then
into
the
car
buretor
spacer
(Fig. 10). The
valve
regulates
the
amount of
air
to
meet
changing operating
conditions.
During idle,
intake
manifold
vac-
POSITIVE
VENTILATION
A1454-B
FIG.
10-Crankcase Ventilating
Systems
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