1968 DATSUN 510 oil additives

22
CHAPTER

FOUR

CD

Normal

plug

appearance
noted

by
the
brown
to

graYish
tan

deposits
and

slight
electrode

wear
This

plug
rndlcates
the
correct

plug
heat

range
and

proper
air
fuel
ratio

f

j

l

Carbon

fouling

dlstrngUlshed
by
dry
fluffy
black

carbon

deposits
which

may
be
caused

by
an
over

nch
alr
fuel
mixture
excessIVe

hand

chokrng

clogged
air
filter

or
excessive
Idling

lJ
6

1

4i

Z

011

fouling
rndlcated

by
wet

OIly

depOSits
caused

by
011

pumprng
past
worn

rrngs
or
down
the
rntake

valve

gUides
A
hotter

plug
temporanly
reduces
011

depOSits
but
a

plug
that
IS

too
hot
leads
to

pre

IgmtlOn
and

possible
engrne
damage
Red
brown

yellow
and
white

coatrngs
caused

by

fuel
and
011
additives
These

depOSits
are
not
harm

ful
If

they
remarn

rn
a

powdery
form

C

I

Shrny
yellow
glaze
on
rnsulator

cone
IS
caused

when

the

powdery
depOSits
from
fuel
and
011
additives

melt

Meltrng
occurs
dunng
hard

acceleration
after

prolonged
Idling
This

glaze
conducts

electnclty

and
shorts

out
the

plug

Overheated

plug
rndlcated

by
burned
or
blistered

rnsulator

tip
and

badly
worn
electrodes
This
condl

bon

may
be
caused

by
pre
Igmtlon
cooling
system

defects
lean
air

fuel
ratiOS
low
octane
fuel
or
over

advanced

Igmbon
bmrng

Spark
plug
condition

photos
courtesy
of
At

Spark
Plug
DIvision
General
Motors

Corporation

The

procedures

given
below
would

generally

apply
to
eIther

type
In
the
dual

pomt
system

one
set
of

pomts
IS
known
as
the
advance
set

and
the
other
the
retard
set

Complete
details

are

given
m

Chapter
Nme

Figure
4
IS
a
detaIl

of

the
dual

pomt

system

1
Remove
dIStnutor

cap
Clean

It

carefully
to

remove

grease
or
dIrt

2
Examme
the
mSIde
of
the

cap
for
d1rt
or
ex

ceSSIve
wear
Look
for

SIgns
of
carbon
tracks
arcmg
from
contact
to
contact
mSIde
the
dIS

trIbutor

cap
Carbon
tracks
mdlcate
defects
or

cracks
and
If
found
the

cap
should
be

replaced

3
Remove
the
rotor
and

mspect
for
exceSSIve

wear
around
the

top
metal
contact

wiper
surface

If

defectlve
replace
As

a
matter
of

good

prac

nce
the

rotor
should
be

replaced
whenever
the

contact

pomts
are

replaced

4
Use
a
screwdriver
to

gently
open
the
contact

pomts
If

they
show
wear
or

plttmg
remove
the

I

7
r

P

r
OVll

t
ate

I
l
h
l
JlA

ye
I
o

ctg
fI

O
0

I
d

1e
d
c

Ji
uo
JJ

cb
c
s
rlr
I

l
4

c
1
2

24

CHAPTER
FOUR

block

and
should
be
used
as
the
reference

point

m

II
1akmg

adjustments

6
With
a

piece
of
white
chalk
mark

a
hne
down

the
center
of
the

pomter
and
mark
the

timing

groove
on
the
crankshaft

pulley
which

IS
to
be

used
m

tImmg
the

engine
SpecIficatIon
for
tun

ing
reqUIres
trlhmg
at
10

degrees
before

top

dead
center
wluch
would
be
the

fourth
mark

from
the
left
end
of
the

row
of
marks

7
Loosen
the
hold
down
bolt
at
the
base
of
the

dlstnbutor

8
Locate
the
slow

speed
1
Ile

adjustIng
screw
on

the
carburetor

so
that
Ile

speed
can
be

adjusted

whIle

runnmg
Also
locate
throttle

adJustmg

screw

9
Start

engme
and

adjust
speed
With
the

adJust

ing
screws
to
the

readmgs
below

Smgle
pomt
dIStributor
600

rpm

Dual

pomt
trlbutor
700

rpm

10
Alternate

adjustment
of
the
two
screws

untIl
the
smoothest
Idle
at
the

proper
speed
IS

achieved

11
Pomt
the

tlIrung
lIght
at
the

stationary

pomter
When
the

lIght
flashes
the

timmg
mark

n
the
crankshaft

pulley
should

hne

up
With
the

mark
on
the

stationary
pomter
If
It
does
not

exactly
Ime

up
rotate

the
dlstnbutor

gradually

untIl
the
marks

align
mdlcatlng
correct

timmg

12
Shut
off
the

engme
remove
the

tmung
lIght

and
tachometer

tighten
the
hold
down
bolt
on

the
dlStnbutor
and
connect
the
vacuum
advance

hne
to
the
tli
tnbutor

IGNITION
TIMING

IDLE

SPEED
IDLE

MIXTURE

DUAL
POINT
DISTRIBUTOR

ONLY

The

followmg
applies
to
velucles
With
dual

pomt
distributor
and
an
exhaust
emission
con

trol
deVice
If
these

procedures
are
followed

ha
ul
exhaust

emisSion
should
be
below
the

maximum
allowable
level

1
Locate
the
Idle

and
throttle

adJustmg
screws

on
the
carburetor

2
Warm

up
the

engine
thoroughly

3
Connect

tachometer
and

tmung
light

4
Set
the

Id
le
speed
at
700

rpm
With
the
Idle

adjust
screw
5

Adjust

IgnltJ
on

tuning
at
10

degrees
before

top
dead

center

6
Increase
the

speed
of
the

engme
to
2
000

rpm

With
the
accelerator

or
throttle

hnkage
and
hold

for
about

15
seconds

7
Return
to
Idle
for
one
mmute

8
Set
the

engme
to
best
Idle
at
750

rpm
770

rpm
for
automatJ
c
transIDlsslOn
With
the
Idle

and
throttle

adJustmg
screws

9
Re

uce

engme
speed
at
700

rpm
720

rpm

for

automatic
transmission

by
turnmg
the
Idle

adJustmg
screw
clockWise
for
a
leaner
IlliXture

10
Connect
a
wife
lead
between
the
advance

ami
retard
Side
tenrunals
See

Figure
4

Speed

should

drop
from
100
to
150

rpm

11
Check

IgIl1tIon
tmung
With

tImmg
light
It

should
now
be
at

top
d
ad
center

12
If
the

tlmmg
IS

nSJt
correct

stop
the

engme

and

adjust
the
retarded
breaker

pomt

13
Start
the

engme
and
reclieck
ili

tmung
If

l

incorrect
reset
the
retarded
breaker

pomt
until

it
IS
correct

Repeat
s
nece

s

14
Disconnect
the
wife

bet
reen
the
advance

and
retard
termmals

15
Recheck

tmung
It
should

be
10

degrees

before

top
dead

center

16
If
mcorrect

repeat
the
above

procedures

un
tIl

satIsfactory

17

T
he
Idle

speed
of
automatic
transnllsslOn

vehicles
should

be
about
575

rpm
With
the

gear

j

selector

m
the

dhve

poSltlon
c

t

DWELL
ANGLE
SETIING

1
Connect

the
dwell

angle
meter

2

PLoJust
dwell

angle
to
49

to
55

degrees

OMPRESSION
TEST

I

A

compressIOn
test
IS

performed
to
check
for

worn

piston
nngs
or
to
detect
the

cause
of

a

low

speed
miss
Before

undertaking
the

test

el
llmate
the

pOSSibility
of

sticky
valves

by
usmg

one
of
the

oil
additives

deSigned
for
the

purpose

With
valves
free
test

compressIOn
as

follows

1
Run
the

engme
for
15
to
20
mmutes
untIl

normal

operating

temperatures
are
obtained

2
Shut
off

engme
remove
arr
cleaner
and