Ford Thunderbird 1958 - Ignition Timing; Distributor Tests, Adjustments, and Minor Repairs; Spark Advance Control Mechanism

PART
2
IGNITION SYSTEM
1-49
3
B.T.C.
CONVENTIONAL
DRIVE AND
OVERDRIVE
FIG.
10
Timing
Marks
spark
plug
wire
is
positioned
in the
brackets as indicated
in Fig. 9.
IGNITION
TIMING
The
engine has
a crankshaft dam
per
having
five
timing
marks
(Fig.
10). The
first
long
mark represents
top
dead
center
(T.D.C.)
and each
succeeding
mark
represents
2, 4,
6,
8,
10,
respectively,
before
top
center
(B.T.C.).
The
initial
timing
should be
set at
3
B.T.C. on con
ventional
drive
or overdrive
units
and
6
B.T.C.
on
cars with
Cruise-O-
Matic.
CHECKING
TIMING
WITH A TIMING
LIGHT
1.
Disconnect
the
distributor
vacuum
line,
then connect the
timing
light
high
tension lead to the
No. 1
6
B.T.C
CRUISE-O-MATIC
1571-A
FIG.
11
Checking
Ignition
Timing
<
,1772-A
spark
plug
and
the other two
leads
of
the
timing
light to
the
battery
ter
minals.
2. Clean
the dirt from the
timing
marks,
and if
necessary,
chalk the
proper
mark and
the pointer to im
prove legibility.
3. Operate
the engine at idle
speed.
Be sure the
engine
is
idling
below
550
rpm
so that
there will be
no cen
trifugal advance.
The
timing
light
should
flash
just as the proper mark
lines
up
with
the
timing
pointer,
indi
cating
correct timing.
The
operator's
eye should be in line with
the center
of the damper and
the
timing
pointer.
4. If
the proper
timing
mark
and
the
timing
pointer
do not
line
up,
rotate the distributor until
the correct
mark and
the pointer are in
line
(Fig.
11).
The
timing
is
advanced
by
clock
wise rotation of
the
distributor
body,
and
retarded
by
counterclockwise
ro
tation.
5. After
the ignition
timing
has
been
properly
set,
connect
the
dis
tributor vacuum
line,
then check
the
distributor
to
determine if
the ad
vance mechanism is
operating.
To
do
this,
hold the
timing
light
so
that
the
timing
marks
and
pointer
can be
seen,
and
accelerate the
engine.
If
no
ad
vance
is
evident,
one of
the
following
is
the
probable
cause;
no
vacuum
available at
the
distributor,
vacuum
advance
diaphragm
leaking
or
dis
connected
from
the
breaker
plate,
centrifugal
advance not
functioning
properly,
breaker
plate
binding
in
the
housing
or
on
the
bushing.
DISTRIBUTOR
TESTS,
ADJUSTMENTS,
AND
MINOR
REPAIRS
This
section covers
the
tests,
adjust
ments,
and
minor
repairs
for
the
distributor.
SPARK
ADVANCE
CONTROL
MECHANISM
The
spark advance
control
mechanism
should
be
tested
during
a
tune-up,
when
the
distributor
is
over
hauled,
on
a
new
installation,
or
whenever
spark
advance
trouble
is
indicated.
DIAPHRAGM LEAKAGE
AND FREENESS
OF
OPERATION
These
tests
can
be made with
the
distributor
installed on
the
engine
or
on
a
distributor test
set.
The
tests
are
sufficient for an
engine
tune-up.
How
ever,
if
there
are
indications
that the
spark
advance
is
not
functioning
properly,
remove the distributor
from
the
engine
and
check
it
on
a
distribu
tor
test
set
following
the
instructions
under
"Spark
Advance
Tests
and
Adjustments."
Check
the
vacuum
advance
mecha
nism
for
freeness
of
operation
by
manually
rotating
the
breaker
plate
in
the
direction of
rotation.
Do
not
rotate
the
plate
by
pushing
on
the
condenser
or
the
points,
use
a
hook
or
other
suitable
instrument
in
the