reset DATSUN B110 1969 Service Repair Manual

Page 45 of 136


Icnition
Sptem

Ovcrhc
Jtmg

Norm
Jl
i
r

rJ
I

ttr
I
i

V

Carbon
fould

Fig
85

Spark
plug
Life

plug
heat

range

Carbon
fouled

Dry
fluffy
carbon

depo
lts
on

the

Insulator
and
electrode

were

mostly

caused

by
slow

speed
dnvlng
In

cIty
weak

Ig

nltlOn
too
nch
fuel

mixture

dirty
aIr
cleaner

etc

It
IS
advIsable
to

replace
WIth

plugs
havmg

hotter

heat

range

011

fouled
Wet
black

depoSits
show

excesSive

oIl
entrance

Into
combusllon

chamber

through

worn

rmgs
and

pIstons
or
excessIve
clearance

between
valve

gUIdes
and

stems
If
the

same

condition

remams
after

repair
use
a
hotter

plug

Overheatmg
WhIte

or

hght
gray
msulator

WIth

black
or

gray
brown

spots
and

blUIsh

burnt
electrodes
indIcate

engme
overheatIng

Moreover
th
e

appearance
results
from
in

correct

IgnitIon

tIming
loose

spark
plugs
low

guel
pump
pressure
wrong
selectIOn

of
fuel
a

hotter

plug
etc

It
IS
adVisable
to

replace
WIth

plugs

havmg

colder

heat

range

After

cleaning
dress

electrodes
With

a
small

fine
file
to
flatten

the
surfaces
of
both

center

and
Side

electrodes
In

parallel
Set

spark
plug

gap
to

specification
FIg
86

Settmg
spark

plug
gap

Install

spark
plugs
and

torque
each

plug
to
11

to
15
ft
Ib

Connect

spark
plug
wires

Cleaning
and

Regap

Clean

spark
plugs
In

a
sand

blast

type

cleaner
A
VOId

excessIve

blasting
Clean
and

remove
carbon

or
OXide

depoSits
but
do
not

wear

away
porcelain
If

depos1ts
are
too

stub

born
discard

plugs

After

cleaning
spark
plugs
renew

firing
sur

face
of
electrodes
With
file

mentioned
above

Then

gap
spark
plugs
to
0
030
to
0
035
In

uSing
a
round

wire
feeler

gauge
All

spark

plugs
new
or
used
should

have
the

gap

checked
and
reset

by
bending

ground

electrode

II