Spark Plugs - Datsun 1973 510 Repair Manual

22 TUNE UP AND TROUBLESHOOTING
Keep the socket stralj ht
on
the
plug to
aVOId breakmg
It
spark plug
wire
gauge
for
checkmg
the
gap
The
WIre
should
pass
through
the
electrode with just
a
slight drag Usmg
the electrode
bendmg
tool
on
the end of
the
gauge
bend the Side electrode
to
ad
t
1
j
T
Gap the
spark plug
with
a
wife
gauge
just the
gap Never
attempt
to adjust
the
center
electrode
Lightly
Oil the threads
of the
replacement
plug
and mstall
It
hand
tIght It
IS a
good
practIce
to
use a
torque wrench
to tIghten
the
spark plugs
on
any
car
and
especially
on
the
Datsun
smce
the head
IS
alummum
Torque
the
spark
plugs
to
14 22
ft lbs Install the
Ig
mtIon
WIre
boots
firmly
on
the
spark
plugs
Checking
and
Replacing
Spark Plug
Cables
Visually
mspect the
spark plug
cables
for burns
cuts
or
breaks
m
the msula
tIon
Check the spark plug boots
and
the
mpples
on
the dlstnbutor
cap
and COli
Replace
any
damaged
wmng
If
no
phYSI
cal damage
IS
obVIOUS the
WIres can
be
checked With
an
ohmmeter for
excessive
resistance
Remove
the dlstnbutor
cap
and leave the
WIres
connected
to
the
cap
Connect
one
lead of the
ohmmeter
to
the
correspondmg electrode mSlde
the
cap
and the other lead to
the spark
plug ter
mmal
remove
It
from
the
spark plug
for
the
test
Replace
any WIre
whICh shows
over
50 000
ohms
Generally speakmg
however
resistance
should
not
run
over
35 000
ohms and
50 000
ohms should be
conSidered the
outer
limits of accept
ability
Test
the COli
WIre
by
connectmg
the ohmmeter between the
center
con
tact
m
the
cap
and either of the
pnmary
termmals
at
the COlI If the total
resIs
tance
of the COlI and cable
IS
more
than
25 000
ohms
remove
the cable from the
coli and check the
resistance
of the cable
alone If the
resistance
IS
higher
than
15 000
ohms
replace
the cable
It
should
be remembered that
WIre
resistance
IS
a
functIon
oflength
and that the
longer
the
cable the greater the
resistance
Thus
If
the cables
on
your
car are
longer
than the