Ford Thunderbird 1957 - Manifolds and Exhaust Gas Control Valve; Exhaust Gas Analysis; Manifolds; Exhaust Gas Control Valve

1-10
Chapter
1
General Engine
Service
distribute
the
oil
and
repeat
the
compression
test. The
oil
will
temporarily
seal
leakage
past the
rings.
If
ap
proximately
the
same
reading
is
obtained,
the
rings
are
satisfactory,
but
the
valves
are
leaking. If
the
com
pression
has
increased 10
pounds or
more
over
the
original
reading,
there
is
leakage past the
rings.
During
a
compression
test,
if
the
pressure
fails to
climb
steadily
and
remains the
same
during
the
first
two
successive
strokes,
but
climbs
higher on
the
suc
ceeding
strokes,
or
fails
to
climb
during
the
entire
test,
it
indicates a
sticking
or
stuck
valve.
Exhaust
Gas
Analysis
An
exhaust gas analysis is
a
method
of
testing
the
ratio
of fuel
and
air
entering
the
cylinders,
and
the
adjustment and
performance
of
the
carburetor.
How
ever
it
cannot
be
used
to calibrate a
carburetor.
As
there are various types
of
analyzers,
follow the
instructions
of
the manufacturer. On
a dual
exhaust
system,
install
the analyzer in the
outlet pipe
opposite
the
side
of the
system
that
contains
the exhaust gas
control valve. For
example,
if
the
valve
is
on the right
side,
install the analyzer
in
the
left muffler outlet
pipe.
3.
MANIFOLDS AND EXHAUST
GAS
CONTROL VALVE
Hot
exhaust
gases are
diverted into the
intake
mani
fold to
provide
the
heat
necessary
to
vaporize
the
in
coming
fuel-air
mixture
and to
minimize engine
stalling
and
carburetor
icing
during
cold engine
operation. The
hot
exhaust
gases are
directed
into
the
intake manifold
by
a
thermostatically
controlled valve
located
in the
exhaust
manifold.
On
the
6-cylinder
engine,
the
hot exhaust gases
are
directed
into a
chamber
(heat
riser)
which
is cast into
the
intake
manifold
section
where
the carburetor and
exhaust manifold
are
attached.
All
8-cylinder intake
manifolds
contain
a
passage
through
the
center
section
and
under
the
carburetor,
through which the
hot
exhaust gases are
directed.
Manifolds
Clean
the
manifolds
in a
suitable
solvent,
then
dry
them
with compressed
air. Scrape
all
carbon
deposits
from
the center exhaust
passage
below
the carburetor
CLOSED
(HEAT
ON)
OPEN
(HEAT
OFF)
heat riser
of the intake manifolds. This
carbon
acts
as
an
insulator
restricting
the
heating
action of the hot
exhaust
gases.
Blow out
the automatic choke passages
of the
8-
cylinder
intake manifolds with compressed air.
Make
sure
the passages
are
completely
open,
otherwise
choke
operation will be
impaired.
On
intake
manifolds used
with a
four-barrel car
buretor,
check
the fresh air
heat tube that
passes
through the
manifold
for
leaks,
as follows:
Adjust a vacuum
pump
to
obtain
a
steady reading
of
three
inches
of
vacuum. Block off one
opening
of
the
tube with a
moistened
finger,
then
connect the
vacuum
pump
hose
to
the
other opening.
If
the
pump
does not
maintain a
steady
reading
there
is a
leak
in
the
tube
and
the
tube
should
be
replaced.
Inspect the
manifolds
for
cracks,
leaks,
or other de
fects that
would
make
them
unfit for further service.
Replace all
studs that
are
stripped
or otherwise
dam
aged.
Remove
all
filings
and
foreign matter
that
may
have entered
the
manifolds as a result
of
repairs.
Exhaust
Gas
Control
Valve
Check
the thermostatic
spring
to
make
sure
it
is
CLOSED
(HEAT
ON)
1001 -A
Fig.
7
Exhaust
Gas
Control
Valve
8-Cylinder Engines
Fig.
2
Exhaust
Gas
Control
Valve
6-Cylinder
Engine