1968 DATSUN 510 Service Repair Manual

CHAPTER
FOUR

ENGINE
AND
IGNITION
TUNE
UP

For
best

performance
and

economy
care

must
be
taken
in

perfornnng
tune

ups
While

accuracy
is

required
the
task
IS
not
d1flicult
if

the

steps
m
tlus

chapter
are
followed

carefully

Cars
used

pnmarily
m

CIty
stop
and

go
dnv

ing
WIll

reqwre
attention
more

frequently
than

those
used

on

highways
ThIs
is
because
the

engme
does
not
reach
full

operatIng
temperature

ConsequentlY
valves
tend
to
stick

compression

drops
and

engme
operatIon
becomes

rough

A
tune

up
IS
adVISable

every
6
000
miles
or

sooner

dependmg
on

type
of

driving
Every

12
000
nu1es
the

spark
plugs
and

ignitIon
break

er

pomts
should
be

replaced
not

Just
cleaned

and

adjusted

A
mmor
tune

up
consISts
of

checking
battery

condItIon

cleanmg
gapping
or

replacmg
spark

plugs
and
dIstnbutor
breaker

pomts
adjustIng

dIStnbutor
dwell

angle
adjusting
IgnitIon
tun

mg
and

settIng
the
carburetor
Idle
mixture
and

idle

speed
A

major
wne

up
includes
the
above

items

plus
igllltIon
compressIOn
valve
clear

ance
carburetor
emISsion
control
deVIce
and

electncal
checks
and

adjustments

Tune

up
Equipment
Required

The

follOWIng

eqUIpment
IS

required
Chap

ter
Two

provides
a

bnef

descnption
of
the
test

eqwpment
I
Voltmeter
ammeter
and
ohmmeter

2

Hydrometer

3

CompressIOn
tester

4
Vacuum

gauge

s
Dwell
meter

6
Tachometer

7
I

StrobOSCOpIC
tmung
lIght

8
Feeler

gauges

9

Torque
wrench

10
Assorted
hand

tools

Connection
of
Tune

up
Equipment

Follow
the

manufacturer
s
recommendations

for
the
use
of
test

eqwpment
If

pOSSible
Figme

1
IS
a
basiC
schematic

diagram
applicable
to

CD

10
Battery

I
TIm1Illbght

T
8Ier

spa
k
plup

ENGINE
AND
IGNITION
TUNE
UP
21

many
types
of
test

eqUipment
and

may
be
used

as
a

gUide
If
the
manufacturer

s

mstructioQs
are

not
aVailable
Connections
shown
in

Figure
1

are
as
follows

1
Voltmeter

a
PosItive
lead
to
resistor
side
of
COli

b

Negative
1
ead
to

ground

2

Tlmmg
Light

a
PosItive
lead
to

posItive
battery
termmal

b

Tngger
lead
to
number
1

spark
plug

c

Negative
lead
to

ground

3
Tachometer

a
PosItive

lead
to
dlstnbutor
Side
of
coil

b

Negative
lead
to

ground

4
Dwell
Meter

a

PosItive
lead
to
dlstnbutor
Side
of
COlI

b

Negative
lead
to

ground

BAlTERY
INSPECTION
AND
SERVICE

1
Check
the
level
of
the

electrolyte
m

battery

cells
If

necessary
replemsh
with
distilled
water

Do
not
overfill

2

Measure
the

speCific
gravity
of
the

battery

electrolyte
Refer
to
the

followmg
table
2
Use
the

proper
size
socket
and
wrench
to

remove

spark
plugs
from
the

cyhnder
head

Make
certam
that
the

gaskets
are
removed
from

the

spark
plug
holes

3

Wipe
off
the
msulator
With
a
clean

rag
to

remove

grease
and
dirt

4

Carefully

mspect
the
msulator
and

body
of

each

plug
for

signs
of

cracks
or

chips

Replace

If

faulty

5

Inspect
spark
plug
threads
and
electrodes
for

damage
or
excessive
wear

Replace
as

requrred

Figure
2
shows
the

cond1t
J
on
of

normal
and
de

fectIVe

spark
plugs
along
with

an

explanation

of
the

causes
of

the
abnormal
conditions

6
If
the

spark
plugs
are
still
serviceable
clean

them

thoroughly
With
a

stiff
brush
or

preferably

With
a
sand

blasting
type
of
cleaner

7
File
the

center
electrode

so
that

It
has

a
fiat

surface

8
File
the
surfaces
of
the
outer
electrode

so
that

all
surfaces

are
fiat
and
smooth

9

Usmg
a
feeler

gauge
adjust
clearance
be

tween
the
electrodes
to
0
031
to
0
035
m
0
8

to
0
9mm
as
shown
m

Figure
3

Full

Charge
Value

CD
68

degrees
F

PermiSSIble
Value
20

degrees
C
3

Frigid
chmates

Tropical
chmates

Other
climates
Over
1
22

Over
118

Over
1
20
128

123

126

3
Clean

top
of

battery
and
termmals
With
a

solutIOn
of

bakmg
soda
and
water
Rmse
off
and

dry
thoroughly
Top
of

battery
must
be
clean
to

prevent
current

leakage
between
termmal
and

from

pOSitive
termmal
to
hold
down

clamp
Pro

longed
accumulatIOn
of
aCid
and
dirt
on

top
of

battery
may
cause

blIstenng
of
the
matenal
cov

enng
on
the
connector

straps
and
detenoration

of
the

straps
themselves

4

Tighten
the
cable

connectors
to
the
termmal

securely

5
Coat
the
termmals

lIghtly
With

petrolatum
to

protect
them
from
corrosion

SPARK
PLUGS
INSPECTION

AND
SERVICE

1
Remove

spark
plug
WIres
Mark
them
to
fi

sure
correct

replacement
J

J

I

I

j

j

10
Remstall

spark
plugs
Make
certam
to
use

a
new

gasket
for
each

plug
Use
a

torque
wrench

to

tighten
spark
plugs
from
11
0
to
150
ft
lb

1
5
to
2
0

kg
m

11
Remstall
WIres

DISTRIBUTOR
INSPECTION

AND
SERVICE

Dependmg
on
the
model

year
velucles
have

a

smgle
pomt
or
a
dual

pomt
dlstnbutor

system

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

ENGINE
AND
IGNITION
TUNE
UP
23

CD
ADJUSTING
SCREWS
FOR
THE
POSITION

OF

RETARDED
BREAKER
POINT

r

A
O
S

8

6

C

0

18

2
6
10
14

contact

pomt
assembly
from
the
dIStnbutor
and

clean
or

replace
the

pomts
Use
a

pomt
file
to

clean
the
contacts
Do
not

attempt
to
remove
all

roughness
Apply
a
trace
of

beanng
lubncant

to
the
breaker
cam

5
Once
the

pomts
have
been
cleaned
or
re

placed
mstall
the

assembly
m

the
dlstnbutor

Make
certam
to
reconnect
wires

6

Adjust
the

pomt
gap
Figure
S
With
the
use

of
a
screwdnver
and

gap
gauge
Make
certaIn

the

rubbmg
arm
on
the
contact

assembly
IS
rest

mg
on
the

hIgh
pomt
of
the
carn
Pomt

gap

should
be

adjusted
to
0
0177

through
00217

m

0
45
to
0
55mm

CD

7
Check
condenser

capacItance
for

a

readmg
of

o
22

through
0
24
mIcrofarads

Replace
If
de

fectIve
As
a
matter
of

good

practIce
the
con

r
denser
should
be

replaced
whenever
the

pomts

are

replaced

8

Inspect
the
InSulatIon
on
all
WIres
WIthIn
the

dIStributor

Replace
If
defectIve

9

Inspect
the
WIre
towers

atop
the
dIStnbutor

cap
for

SignS
of
dIrt
or
corrosIOn
A

pencIl
wIth

fine

emery
cloth

wrapped
around
the

erasl
e
end

can
be
used
to
clean
and
burnISh
the
metal
sur

faces
Make
certam
to
blowout

any
dust

10

Replace
the
rotor

md
the

cap
on
the
dIs

tnbutor
and
secure
the
two
hold
down

clamps

FI

ly
msert

IgrntIon
WIres
mto

proper
towers

ill

cap

IGNITION
TIMING

IgmtIon
tIDlIDg
is

adjusted
with
the

engine

runnmg
Use
a

strobOSCOpIC
timing
hght
and

pro

ceed
as
follows

1
Make
certam
that

spl
l
k

plug
gaps
and
dIs

tnbutor
contact

pomts
are

accurately
set

2
DISconnect
the
vacuum
hne
from
the
carbu

retor
at
the
dIstrIbutor

Plug
the
end
of
the

vacuum
hne
wIth

tape
or
a
wooden

stopper

3
Hook

up
the

trmmg
light
per
mstructIons

4
Hook

up
tachometer

per
mstructions

5
The

tImmg
marles
are
located
on
the
front

edge
of
the
crankshaft

pulley
The

grooves
are

graduated
m
5

degree
mcrements
The

top
dead

center
mark
S
located
to
the
extreme
left
hand

sIde
of
the

engme
as
vIewed
from
the
front
A

statIOnary
pomter
S
connected
to
the

cylinder

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

ENGINE
AND
IGNITION
TUNE
UP
4

25

block
the
throttle
and
choke
m
the
WIde

open

position

3
Remove
all
four

spark
plugs

4

Sequentially
press
a

compressIOn
test

gauge

mto
each
of
the

spark
plug
holes
and
crank
the

engme
for
at
least
four
strokes
Record
the
com

pressIOn
readmg
for
each

cylmder
Standard

compressIOn
readmg
IS
171
Ibs
m
12
0

kg
cm
Mmlmum

acceptable
readmg
IS
159

lbs
m
2

11
5

kg
cm

5
No

readmg
should
be
less
than
80
of
the

highest
cylmder
reading
ExceSSive

vanatiC
ns

between

cylmders
accompanied
by
low

speed

mlssmg
of
the

cyhnder
or

cylmders
that
read

low

usually
mdlcates

a
valve
not

properly
seat

mg
or
a
broken

piston
ring

Low

pressures
even

though
uniform

may

mdicate

worn

nngs
ThIS

IS

especlall
true
1f
ex

cessive
011

cQIlsumptlon
has
been
noticed
If
one

or
more

cylmders
read
low

or
uneven

inject

about
a

tablespoon
of

engine
ail

on

top
of
the

piston
of

that

cylinder
and
crank
the

engine

several
tlmes

noting
the

compressIOn
reading

If

compressIOn
has
nsen
the

piston

nngs
or

cylmders
are
worn
and
should

befserviced
If

compressIOn
has
not

unproved
after

addmg
oil

the
valves
are

Stlcking
or
are
not

seating

prop

erly

If
two

adjacent
cylmders
have
low

compres

sion
and

mjectmg
01

9es
not
increas
the
read

mg
the
head

gasket
between
the

cylmders
IS

probably
leaking

VALVE
CLEARANCE
ADJUSTMENT

Valve

adjustment
should
be
done
in
two

steps
first
With
the

engme
cold
and
then
at

operatmg
temperature
Refer
to

Figure
6

and

proceed
as
follows

1
Remove

arr
liter

2
Remove
rocker

arm
cover
Take

care
not
to

damage
the

gasket

3
Remove
the

spark
plugs
and

rotate
the
en

gine
unt1l
number
1

cylinder
IS
at

top
dead
center

o
l
the

compressIOn
stroke
This
can
be
de

tepnmed
w
hen
the

top
dead
center
mark
on

the
crankshaft

pulley
is

m

alignment
With
the

statIOnary

pomter
and
both
valves
for

number

1

cylmder
are
closed

I
4

Counting
from
the
front
of
the

engme
ad

Just
valves
1
2
3

and
5
as
follows
Loosen
the

pivot
lockmg
nut
and
turn
the

pivot
screw
unt1l

clearance
between
the

pivot
screw
and
the
rock

er
ann
IS
0
0079

m
0
200mm
for
the
mtake

valves
and

0
0098
in
0
25mm
for
the

exhaust

valves
Check

clearances
With

a
feeler

gauge
as

shawn
When
correct

tlghten
the

pivot
locking

nut

l

1

5
Rotate
the
crankshaft
unt1l
the
number
4

pISton
IS
at

top
dead

center
an
the

compressIOn

stroke
This

IS
one

complete
revolution
of
the

crankshaft

Agam
the
0

degree
mark
should

align
With
the

pomter
and
both

valves
on
num

ber
4

cylinder
should
be
closed

6

Adjust
valves
4
6
7
and
8

as
above

i

I

7

Replace
spark
plugs
Ignition
WIres

r
ick
r

1

arm
cover

gasket
and
air
filter

8
Start

engine
and

run
it
unt1l

operating
tem

perature
IS
reached

9
Remove
rocker

ann
cover
and

repeava
iius

ment
Clearances
should
be

0
0098

m
0

25fumj

for
the

mtake
valves
and
00Il8
m
0
30mi

for
the
exhaust
valves
Check
clearances
before

loosening
the

pivot
lockmg
nuts
as

they

may

already
be

properly
set
If

not

adjust
as
re

quir
l

ADDmONAL

CHECKS

l

Qunng
tune

ups
check
the

followmg
Ite

far

SignS
of
defects

or
excessive
wear
I

i

1

Inspect
the
carburetor
for

buildup
of

foreign

matenal

Pay
Special
attention
to
the

throat
and

linkages
Clean
or
overhaul
as

required
Det8
1ls

for
carburetor
mamtenance
are

given
in

Chapter

seven

26

CHAPTER

FOUR

2
Check
all
belts
hoses
and
fuellmes

Replace

If

reqUIred
Check
the
tensIon
of
the
belts
for

the
au

pump
and
the
alternator

Adjust
as
re

qUIred
Normal
deflection
of
the
belts
when
pushed
m

by
hand
should
be

approXImately
0
5

m

13mm
as
shown
m

Figure
7

3

Inspect
the
011
filter
for
leaks

TIghten
or
re

place
as

necessary
The
filter
should

replaced

at
least

every
6
000
mIles

4

Inspect
the

lIlr
cleaner

for
excessIve
accumu

latIon
of
dIrt

Replace
at

least

every
24
000
miles

under
normal

operatmg
cornhtIons

5

Carefully

mspect
the

water

pump
and

the

radIator
for

SIgnS
of

leaks

Repair
as

necessl
i
y

6
Check
the
emissIoo
control
deVice
If

so

eqwpped
Refer

to

Chapter
Ten
for

checks
and

tests

to
be
made

c

1

7
Check

engine
oIl

Replems
9
or

replace
as

reqUIred

8
Check
the

level
of
the
brake

fluid
m

the
brake

and

clutcJ1
master

cylmder
reservOirs

ReplenISh

as

necessary

ii
t

d

fl

tlJ

l

f

CH
APTER
FIVE

I

f

I
t

p

ENGINE
LUBRICATION
SYSTEM

i

k

i

DESCRIPTION

The
Datsun
L16

engme
uses
a

pressure
feed

011

system
Figure
1
Illustrates
the
flow
of
the

engine
011

Refer
to

Chapter
Two
for
the
re
om

mended

type
of
011
and
the

frequency
that

chang

mg
IS
recommended
LUBRICATION
CIRCUIT

OlliS
drawn
from
the
011

pan
through
the
mlet

screen
and
tube
to
the
mlet
side
of
the
011

pump

011
flows

through
the
outlet

portIon
of
the
011

pump
and
the
011

gallery
to
the
mlet
side
of
the

011
filter
and
then
to
the
maID

gallery
The
mam

CD

N

4
r

I