check engine light DATSUN 510 1968 Service Repair Manual

10
CHAPTER
THREE

pressure
bUllt

up
In
each

cylInder
The

readIngs

when

properly
Interpreted
IndIcate

general
cyl

Inder
and
valve
condltlOn

Vacuum

Gauge

The
vacuum

gauge
IS

easy
to
use
but
dIfficult

for
an

Inexpenenced
mechanIC
to

Interpret
The

results
when
conSIdered
WIth
other

findIngs
can

prOVIde
valuable
clues
to

pOSSIble
trouble

Connect
the
vacuum

gauge
WIth

a
T
connec

tIon
In
the
hose
from
the
carburetor
to
the

vacuum
advance
on
the
dIstnbutor
Start
the

engme
and
let
It
warm

up
thoroughly
Vacuum

readIng
should
be

steady
at
18
22
Inches

NOTE
Subtract
1
Inch

from

reading

for

every
1000

feet
of
altitude

Figure
1
shows
numerous

tYPical
readIngs

WIth

InterpretatIons
Results
are
not
conclusive

WIthout

companng
to
other
tests
such
as
com

preSSIOn
readIngs

Fuel
Pressure

Gauge

ThIS
Instrument

IS
VItal
for

evaluatIng
fuel

pump
performance
Often

a
vacuum

gauge
and

fuel

pressure
gauge
are
combIned

Dwell
Meter

A
dwell
meter
measures
the
dIstance
In
de

grees
of
cam
rotatIon
that
the
breaker

pOInts

remaIn
closed
while
the

engme
IS

runnIng
SInce

thIS

angle
IS
determmed

by
breaker

pOInt
gap

the
dwell

angle
IS
an
accurate
IndIcatIon
of

pOInt

gap
Many
tachometers
Intended
for

tunIng
and

testIng
Incorporate
a
dwell
meter
as
well
Follow

the
manufacturer
s
InstructIon
to
measure
dwell

on
the
Datsun

Tachometer

A
tachometer
IS
essential
for

tunIng
Datsuns

WIth
exhaust
emission
control
deVices

IgmtIOn

turung
and
carburetor

adjustments
must
be

per

formed
at
the

specified
Idle

speed
The
best
In

strument
for
thIS

purpose
IS
one
WIth

a

range
of

0
1
000
or
0
2
000

rpm
Extended

range
0

6
000
or
8
000
Instruments
lack

accuracy
at

lower

speeds
The
InStrument
should
be

capable

of

detecting
changes
of
25

rpm
Stroboscopic
Timing
Light

ThIS
Instrument

pernuts
accurate

IgnitIon

tImIng
By
f1ashmg
a

bght
at
the

preCISe
Instant

cylInder
No
1
fires
the

posItIon
of
the
crank

shaft

pulley
at
that
Instant

can
be
seen
Marks

on
the

pulley
bne

up
With

a
reference

pOInter
on

the
block

dunng
the

tIming
procedure
SUltable

bghts
are
neon
bulb

types
and
xenon
strobe

hghts
Neon

tunmg
bghts
are
ddticult
to
see
and

must
be
used
in

dImly
bt
areas
Xenon
strobe

bghts
can
be
used
In

bnght
sunbght
Use
the

bght
accordIng
to
the
manufacturer
s
InStruC

tIons

Exhaust

Analyzer

Of
all
Instruments
descnbed
here
this

IS
the

least

bkely
to
be
owned

by
a
home
mechanic

One
Instrument

samples
the
exhaust

gases
from

the

taIlpIpe
and
measures
the
thermal
conduc

tIVIty
of
the
exhaust

gas
SInce
different

gases

conduct
heat
at

varYIng
rates
thermal
conduc

tIVIty
of
the
exhaust
IS

a

good
IndIcatIon
of

gases

present
This
Instrument
IS
VItal
for

accurately

checkIng
the
effectIveness
of
exhaust
emIssion

control

adjustments
but
IS
too

expenSIve
for
an

amateur
mechanIC
to
conSIder

buying

STARTER

Starter

system
troubles
are

relatIvely
easy
to

ISolate
The

followmg
are
common

symptoms

and
cures

1

Engme
cranks

very
slowly
or
not
at
all

Turn
on
the

headhghts
If
the

bghts
are

very
dun

most

likely
the

battery
or
the

connecting
WireS

are
at
fault

Check
the

battery
using
the

pro

cedures
descnbed

in
the
Tune

up
chapter
Check

wmmgfur
e
s
wom
andd
connectIom

H
the

battery
and

connectIng
WIres
check

good
turn
the

headlIghts
on
and

try
to
crank
the

engIne
H
the

lIghts
dIDl

drastIcally
the
starter
is

probably
shorted
to

ground
Remove
the
starter

and
test
it

usmg
the

procedures
gIven
in

Chapter

NIne
If
the

lights
remain

bnght
or
dun

slIghtly

when

crankIng
the

engme
the
trouble

may
be
in

the
starter
solenOId
or

wmng
To
ISolate
the

trouble
short
the
two

large
solenoid
ternunals

together
not
to

ground
if
the
starter
cranks

normally
check
the
solenoid
and

wmng
up
to
the

12
CHAPTER
THREE

13
IMPROPER
IDLE

MIXTURE

Roats

slowly
between

13
17
14
SMALl
SPARK

GAP
or
DEFECTIVE

POINTS

Slight
float
between

14
16

ignItIOn
switch
If
the
starter
still
fails
to
crank

properly
remove
the
starter
and
test
it

2
Starter
turns
but
does
not

engage
with

engine

This
trouble
is

usually
a
defective

pInion
or
sole

noid

shlfting
fork

It

may
also
be
that
the
teeth

on
the

pInion
flywheel
ring
gear
or
both
are

worn
down
too
far
to

engage

properly

3
Starter

engages
but
will
not

dISengage
when

IgmtlOn
switch
IS
released

TIns
trouble
is

usually
caused

by
a

sticking
sole

nOid
but

occasionally
the

pmlOn
can

jam
on
the

flywheel
With
manual
transmissions
the

pinion

can
be

temporanly
freed

by
rockmg
the
car
in

high

gear
Naturally
this
IS
not

poSSible
in
auto

matics
the
starter
must
be
removed

4
Loud

grinding
noISes
when
starter
runs

TIns

usually
means
the
teeth
on
the

pinion

and
or

flywheel
are
not

meshing
properly
It

may
also
mean
the
over

running
clutch
IS
broken

In
the
first
case
remove
the
starter
and

examine

the

gear
teeth
In
the
latter
remove
the
starter

and

replace
the

pmion
dnve

assembly

CHARGING
SYSTEM

Charging
system
troubles

may
be
in
the
alter

nator

voltage
regulator
or
fan
belt
The
follow

ing
symptoms
are

typical

1
Alternator

warning

lamp
does
not
come
on

when

IgmtlOn
is

turned
on

This

may
indicate
a
defective

ignition
switch

battery
voltage

regulator
or

lamp
Frrst

try
to
15
HEAD
GASKET

LEAK

Roats
between
5
19
16
RESTRICTm

EXHAUST
SYSTEM

Normal
when
first

started

Drops
to
0
as

rpm
Increases

May

eventually
rrse
to

about
16

start
the
car
If
it
doesn
t
start
check

the

igllltlon

sWitch
and

battery

If
the
car
starts
find
the

voltage
regulator
and

disconnect
the
wlute
red
Wire
this
is
the

lamp

wire
Ground
the

wire
If
the

lamp
hghts
the

voltage
regulator
is
defective
not

properly

grounded
try
tightening
the

mounting
screws

or
the
alternator
brushes
are
not

contactmg
the

commutator
If
the

lamp
does
not

light
when
the

wire
IS

grounded
the

lamp
is

probably
burned

out

replace
It

2
Alternator

warning
lamp
comes
on
and

stays
on

This

usually
mdicates
that
no

chargmg
is

takmg

place
Frrst
check
the
fan
belt

tension
and

adlust

if

necessary
Check
the

battery
condition
with

the

hydrometer
and
check
all
electrical
connec

tions
m
the

chargmg
system
Fmally
isolate
the

trouble
to
the
alternator
or

voltage
regulator

3
Alternator

warmng

lamp
flashes
erratically

This

usually
indicates
the

chargmg
system
is

workmg
intermittently
Check
the
fan
belt
ten

sion
and
all
electncal
connections
m
the

charg

ing
system
Check
alternator
brushes
and
cODlh

tlon
of
the
commutator

4

Baltery
reqUires
frequent
additiOns

of
water

or

lamps
require
frequent

replacement

The
alternator
IS

probably
overchargmg
the
bat

tery
The

voltage
regulator
is

probably
faulty

check
it

using
the

procedures
given
in

Chaper

Nme

5
ExceSSive

noISe

from
he
alternator

Check
for
loose
alternator

mountmg
The

TROUBLESHOOTING
13

trouble

may
also
be
worn

bearings
Remove
the

alternator
and

repair

ENGINE

These

procedures
assume
the
starter
cranks

the

engme
over

normally
If
not
refer
to
Starter

section
m
this

chapter

1

Engme
won
t
start

Could
be

caused

by
the

IgOltlon
or
fuel

problems

First
determine
If

high
voltage
to

spark
plug

occurs
To
do
thiS
dISconnect
one
of
the

spark

plug
wires
Hold
the

exposed
wrre
termlOal
y
to

Y2
lOch
from

ground
any
metal
in

engine
com

partment
With
an
msulated
screwdriver
Crank

the

engme
over
If

sparks
do
not

Jump
to

ground

or
the

sparks
are

very
weak
the
trouble

may
be

10
the

IgnitIOn
system
See

Ignition
System
Trou

bleshootmg
to
further
check
If

sparks
occur

properly
the
trouble

may
be
10
the
fuel

system

See
Fuel

System
Troubleshootmg

2

Engme
misses

steadily

Remove
one

spark
plug
wrre
at
a
tune
and

ground
the
wrre
If

engme
mISs
increases
that

cyhnder
was
work

109
properly
Reconnect
the

wire
and
check
the
others
When
a
wire

IS
dIs

connected
and

engme
miss
remams
the
same

that

cylinder
IS
not

finng

Check

spark
as
descnbed
10

Step
1
If
no

spark

occurs
for
one

cyhnder
only
check
dlStnbutor

cap
wrre
and

spark
plug
If

spark
occurs

prop

erly
check

compressIOn
and
mtake
maOlfold

vacuum
to
ISolate
the
trouble

3

Engme
misses

erratlcally
at
all

speeds

Interrmttent
trouble
can
be
difficult
to
find
It

could
be
ill
the

Ignition
system
exhaust

system

or
fuel

system
Follow

troubleshooting
proce

dures
for
these

systems
carefully
to
isolate
the

trouble

4

Engme
misses

at
Idle

only

Trouble
could
exist

anywhere
ill

IgOltlon
system

Follow

Ignition
TroubleshootlOg
procedure
care

fully
Trouble
could
also
eXist
10
the
carburetor

Idle
crrcult
Check
Idle
mIXture

adjustment
and

check
for
restnctions
m
the
idle
crrcUlt

5

Engme
misses
at

high
speed
only

Problems
could
be
ill
the
fuel
or

IgOltlon
systems
heck
accelerator

pump
operation
fuel

pump

dehvery
fuel
hnes
etc
as
descnbed
under
Fuel

System
Troubleshootillg
Also
check

spark
plugs

and
wrres

6
Low

performance
at
all

speeds
poor

acceleratIOn

Trouble

usually
ill

IgOltlon
or
fuel

system
Check

each
With
the

appropnate
troubleshooting
pro

cedure

7
ExceSSive

fuel
consumptIOn

Could
be
caused

by
a

Wide

variety
of

seemmgly

unrelated
factors
Check
for
clutch

shppage

brake

drag
defective
wheel

beanngs
or

poor

front
end

alignment
Check

IgOltlOn
system
and

fuel

system

8
011

pressure
lamp
does
not

light
when

IgmtlOn

switch

IS
on

Check
the
alternator

warning
lamp
If
it
ISn
t
on

either

go
to

Step
1

Chargmg
System
Trouble

shootlOg
If

only
the
oil

pressure
lamp
IS
off

open

the

englOe
compartment
hd
and
locate
the
oil

pressure
sender
on
the
block
near
the
oil
filter

Make
sure
the
wrre
is
connected
to
the
sender

and

makmg
good
contact
Pull
the
wrre
off
and

ground
it
If
the

lamp
hghts
replace
the
sender

If
the

lamp
does
not

light
replace
the

lamp

9
011

pressure
lamp
lights
or

flickers
when

engme
IS

runmng

Indicates
low

or

complete
loss
of
oil

pressure

Stop
the

englOe
unmedmtely
coast
to
a

stop
With

the
clutch

dISengaged
Tlus

may

simply
be

caused

by
a
low
oil
level
or
an

overheatmg
en

glOe
Check
the
oil
level
and
fan
belt
tensIOn

Check
for
a
shorted
oil

pressure
sender
with
an

ohmmeter
or
a

contlOulty
tester
Remove
and

clean
the
oil

dipstick
and
check
oil
level
and

condition

RepleOlsh
or

replace
the
oil

as
re

qurred
Listen
for
unusual
nOISes

mdlcatmg
dam

aged
beanngs
etc
Do
not
re
start
the

engine

until

you
know

why
the

hght
went
on
and

are

sure
that
the

problem
has
been
corrected

IGNITION
SYSTEM

This

procedure
assumes
the

battery
IS
ill

good

enough
condition
to
crank
the

engme
at
a

normal
rate

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

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
55

Cylinder
Block

Assembly

1
PositIon
all
crankshaft

parts
on
a
work
bench

ThIS
mcludes
the
crankshaft
main

beanngs

rear
011

seal
woodruff

keys
crankshaft

gear

011

pump
gear
011
thrower
bolts
and

bearing

caps
Figure
57
shows
the

arrangement

@

2
Insert
maIO

beanngs
mto

appropnate
cy1m

der
block
holders

NOTE
The
center
No
3

beanng
IS

the

only
flanged
type
of
thrust
bear

Ing
Bearings
No
2
and
No
4
are

Identical
No
1
and
No
5

Jaring
ap

pear
identical
but
No
1
as
an
011

hole
All

bearings
except
No
1
are

Interchangeable
as
to

upper
and
lower

half

3

LIghtly
lubncate
the

crankshaft
and

beanng

matmg
surfaces
then
mstall

beanngs
10
mam

beanng
caps

4
Install
the
crankshaft

5
Install
mam

beanng
caps
over

crankshaft

msert
mam

cap
bolts
and

tighten
hghtly
The

mam

beanng
caps
have
an
arrow
marked
on

each
one
These
must

pomt
to
the
front
of
the

engme

6

Gently
move
the
crankshaft
10
an
aXIal
drrec

don

toward
the
front
of
the

engme
to

venfy
that

the
mam

beanng
caps
are

properly
alIgned
and

seated
7
Use
a

torque
wrench
to

tighten
the

cap
bolts

to
the
hmlts

speCIfied
The

t1ghtenmg
operatIon

should
be
done

gradually
10
three

or
four

sep

arate

stages
starting
10
the
center
and

workmg

outward

to
each
end

8
Rotate
the
crankshaft
to
make
certain
it
isn
t

bmding

9
Use
a
feeler

gauge
to
check
the
end

play
at

the
center

No
3

beanng
Figure
58

10
Install
the
SIde
oll
seals
into
the
rear
mam

cap
and

cy1mder
block
as
shown
10

Figure
59

@

11
Install
the
rear
011
seal
WIth
Datsun
tool

ST49370000
or

equIvalent

12
Install
the
rear
end

plate

13
Install
the

flywheel
WIth

proper
bolts
and

lock
washers
and

torque
as

specified

ENGINE
ELECTRICAL

SYSTEM

103

2
Check
the
lead

Wires
of
the
armature
coil

Includmg
the

neutral
wire

for

ground
as
shown

In

Figure
42

HIgh
reSIStance
no
current
flow

indicates

gqod
condItion

If

not
the
stator
must

be

replaced

DIODE

INSPECTION

The
diodes
can
be

inspected
through
the
use

of
a

lamp
and

battery
or
with

a
tester
The

lamp

and

battery
test
can
be
made
Without

disassembl

ing
the
alternator
wh1le
the

tester
should
be
used

when
the
dIodes

are

dIrectly
acceSSIble

1
Positive
Dwde
Test
Connect

the

battery

negative
terrmnal
WIth
the

connector
A
terrmnal

WhIte
and
the

battery

pOSItIve
terminal
With

the
connector
N

terrmnal

yellow
as
shown

m

Figure
43
The

lamp
m
the
circuit
should

hght

@

Reverse
the
connection
as

shown
m

Figure
44

If
the

lamp
does
not

hght
the

pOSItIve
diodes

are

satisfactory
If
the

lamp
does

light
one
or

all
of

the

pOSItIve
dIodes

are
defective
and
must

be

replaced
@

Qg

2

Negative
DIOde
Test

Connect
the

battery

negatIve
termmal
to

the
connector
N
terrmnal

yellow
and
the

battery

pOSItIve
termInal
to
the

connector
E
termmal

black
The

lamp
m
the

CIrcUit
should

lIght
Reverse

the
connectIons
If

the

lamp
does

not

lIght
the

nega1
ve
dIodes
are

satlsfactory
If
the

lamp
does

lIght
one

or
all

I

of
the

negatIve
dIodes

are
defectIve
and
must
be

replaced

To
test
the

indiVIdual
dIodes
With
a
tester

proceed
as
follows

1
There

are
two
kInds
of
diodes
as
shown
m

Figure
45
Check
dlOd
reSIstance

usmg
a
tester

In
both
dIrectIons

as

jl
own
in

Figure
46

f

Current
flow
@

Current
flow

re

ack

flgUre

e

terminal

r

Positive
diode

Negative
diode

@

122

CHAPTER
TEN

1
Start
the

engIne
and

bnng
It

up
to
normal

operatIng
temperature

2

Inspect
all
hoses
and
connectIons
for
leaks

and
detenoratIon
Shut
off
the

engme
Replace

any
defectIve
hoses

3
Remove
the
hose
attached
to
the
check

valve

4

VIsually
Inspect
the

posItIon
of
the
valve

plate
InsIde
the

valve

body
See

Figure
10
It

should

be

lIghtly
posItIoned
agaInst
the

valve

seat

away
from
the
aIr
dlstnbutor
manifold

5
Insert
a

probe
Into
the
valve
connectIon
on

the
check
valve

Depress
the
valve

plate
It

should
return

freely
agaInst
the
valve
seat
when

released

6
Leave
the
hose
dISconnected
and
start
the

engme

7

Slowly
Increase

engine
speed
to
1
500

rpm

Watch
for
exhaust

gas
leakage
at
the
check

valve
There
should

not
be

any
The
valve

may

flutter

or
VIbrate
at
Idle

speeds
ThIS
IS
normal

Replace
the
valve
u

defecuve

Anti
Backfire
Valve

1
Start
the

engme
and

bnng
to

operating

temperature

2

Inspect
all
hoses
and
hose
connectIons
for

leaks
and
detenoratIon

Replace
as

required

3
DIsconnect
the
hose
at
the
antI
backfire

valve

leading
to
the
Intake

manuold
Insert
a

plug
ill

the

hose
and
fasten

securely

4

Open
and
close
the
throttle
valve

rapidly
See

Figure
11
Place
a

finger
over
the
valve
outlet
to

the

m
take
manuold
If

arr
flow
IS
felt
for

one
to
two
seconds
the
valve
IS

functIonIng

properly

If
there
s
no
aIr
or
If
the
flow
is
felt
for
more

than
two
seconds
the
valve
IS
defectIve
and
must

be

replaced

5
Connect
the
alr
hose
to
the
mtake
manuold

after

remOVIng
the

plug

6
DIsconnect
the
aIr
mlet
hose
from
the
air

pump
at
the
antI
backfire
valve
If
the

engine

Idle

speed
changes
excessIvely
the
valve
is
de

fectIve
and
must
be

replaced

Air

Pump

1
Check
the
atr

InjectIon
pump
belt
tension

DeflectIon
of
the
belt
should
be
0
5
In
when

pushed
In

by
thumb

pressure
Adjust
belt
u

necessary

2

Operate
the

engme
untIl
normal

temperature

IS
reached

3

Inspect
all
hoses
hose

connectIons
and
the

arr

gallery
for

SIgnS
of

leaks
or
detenoratIon

Replace
as

required

4
DIsconnect
the
air

supply
hose
at
the
check

valve

5
Insert
the

open
pipe
end
of
a

pressure
test

gauge
adapter
Into
the
air

supply
hose
See

Fig

ure
12

Clamp
the

adapter
firmly
to
the
hose

Install
the

pressure
test

gauge
to

the

adapter

PosItIon
the

adapter
and
test

gauge
so
that
the

alr
blast
emitted

through
the
dnlled

pipe
plug

Will
be

harmlessly

dislppated

6
Install
a
tachometer

on
the

engme
WIth
the

engIne
speed
set
to

1
500

rpm
observe
the

pres

sure

readmg
AIr

pressure
should
be
0
47
m

Hg

16mm
Hg