1969 DATSUN 610 check engine

VALVE
CLEARANCES

Adjusting

Incorrect
valve
clearance
will
affect
the

performance
of

the

engine
and

may
damage
the
valves
and
valve
seats
Insuf

ficient
valve
clearance
will
result
in
loss
of

power
and

may

prevent
the
valve
from

seating
properly
Excessive
clearance

causes
the
valve
to
seat
and
reduces
the
amount
of

valve
lift

This
will
result
in

noisy
operation
with

damage
to
the
valves

and
seats

Adjustment
is
made
with
the

engine
switched
off

and
should
be
carried
out

initially
with
the

engine
cold
to

allow
the

engine
to
run
Final

adjustments
are
made
after

wanning

up
the

engine
to

its
Donnal

operating
temperature
The

engine
can
be
rotated

by
removing
the

sparking
plugs
to
release

the

cylinder
compressions
then

selecting

top
gear
and

pushing

the
vehicle
backwards
and
forwards

The
cold
valve
clearances
should
be
set
to
0
20
mm

0
0079
in
for
the
inlet
valves
and
0
25
mm
0
0098
in
for

the
exhaust
valves
Check
the
clearance
between
the
valve
and

rocker

using
a
feeler

gauge
as
shown
in

Fig
A
40
Slacken
the

locknut
and
turn
the
adjusting
screw
until
the

specified
clearance

is
obtained
then

tighten
the
locknut
and
recheck
the
clearance

The
feeler

gauge
should

just
be
free
to
move
between
the
rocker

and
valve
When
the
cold
valve
clearances
have
been
set
run
the

engine
until
it
reaches
its
normal

operating
temperature
then

switch
off
and

adjust
the
valve
clearances
with
the

engine
warm

to

0
25
mm
0
0098
in
for
the
inlet
valves
and
0
30
mm

0
0118
in
for
the
exhaust
valves

ENGINE
LUBRICATION
SYSTEM
Fig
A
41

OIL
PUMP
Removal
and

Dismantling

The
rotor

type
oil

pump
is
mounted
at
the
bottom
of
the

front

timing
cover
and
driven

by
the
distributor
drive
shaft

assembly

Overhaul
of
the

pump
will

require
careful
measurement

of

the
various
clearances
to
determine
the
amount

of
wear

which

has
taken

place
If

any
part
is
found
to
be
worn
it

may
be
neces

sary
to

replace
the
entire
oil

pump
assembly
To
remove
the
oil

pump
from
the

engine
proceed
as
follows

1
Remove
the
distributor

assembly
as
described
in
the

section
IGNITION
SYSTEM
Remove
the
oil

sump
drain

plug
and
drain
off
the

engine
oil
See
under
the
heading

CHANGING
THE
ENGINE
OIL

2
Remove
the
front
stabiliser
and
the
splash
shield
board

3
Withdraw
the

securing
bolts
and
detach
the
oil

pump

body
together
with
the
drive

gear
spindle

Take
out
the
bolts
securing
the

pump
cover
to
the

pump
body

and
withdraw
the
rotors
and
drive
shaft
See
Fig
A
42

The
pin
securing
the
driven
shaft
and
inner
rotor
must
not

00
taken
out
as
the
shaft
is

press
fitted
to
the
rotor
and
the

pin

is
caulked

Unscrew
the
threaded

plug
and
withdraw
the
regulator

valve
and

spring
Oean
each

part
thoroughly
and
examine
for

signs
of

damage
or
wear
Use
a
feeler

gauge
to
check

the
side

clearances
between
the
outer

and
inner
rotors
the
clearances

at
the

tips
of
the
rotors
and
the
clearance
between
the
outer

rotor
and
the

pump
body
See
Technical
Data
for
the
relevant

clearances
The
clearances
can

be
checked

using
a

straight
edge

as

shown
in

Fig
A
43

OIL
PUMP

Assembly
and
Installation

Assembly
is
a
reversal
of
the

dismantling
procedure
Before

installing
the
oil

pump
in
the

engine
it
will
be

necessary
to

rotate

the

engine
until
the
No
1

piston
is
at

T
D
C
on

its

compression
stroke

Fill
the

pump
housing
with

engine
oil
and

align
the

punch

mark
on
the

spindle
with
the
hole
in
the
oil

pump
as
shown

in

Fig
A
44

Install
the

pump
with
a
new

gasket
and

tighten
the

securing
bolts
to
a

torque
reading
of
1
1
1
5
kgm
8
1
Ilb
ft

Replace
the

splash
shield
board
and
the
front
stabiliser
refill

the

engine
with
the

specified
amount
of

engine
oil

OIL
FILTER

The

cartridge
type
oil
filter
can
be
removed
with
the

special
tool
ST
19320000
or
a
suitable
filter
remover
Interior

cleaning
is
not

necessary
but
the
ftIter

body
and
element
must

be

repiaced
every
10
000
km
6000
miles
Be
care
ul
not
to

overtighten
the
filter
when

replacing
or

oil
leakage

may
occur

CHANGING
THE
ENGINE
OIL

After
the
fIrst
oil

change
which
should
take

place
at
1000

km
600
miles
the
oil
should
be

changed
regularly
at
5000
km

3000
miles
intervals

Draining
is
more

easily
accomplished
after
a

lengthy
run

when
the
oil

being
thoroughly
warm
will
flow

quite
freely

Stand
the
vehicle
on
level

ground
and

place
a
suitable

container
under
the
drain

plug
Remove
the
drain

plug
carefully

as
the
hot
oil

may
spurt
out
with
considerable
force
When

refIlling
the

engine
make
sure

that
the
oil
is
to
the
H
mark
on

the

dipstick

19

CoolIng
System

GENERAL

FAN
BELT
TENSION

FLUSHING
AND
DRAINING
THE
SYSTEM

THERMOSTAT

Testing

RADlA
TOR
Removal

GENERAL

The

cooling
system
is

pressurised
and

incorporates
a

water

pump
corrugated
fin

type
radiator
fan
and
a

pellet
type

thermostat

The
water

pump
is
of
the
centrifugal
type
and
has
an

aluminium
die
cast

body
The
volute
chamber
is
built
into

the

front
cover

assembly
and
a

high
pressure
sealing
mechanism

prevents
water

leakage
and
noise

The
fan

pulley
is
driven

by
the
V
belt
from
a

pulley
on

the
crankshaft

he

pellct
type
thermostat
enables
the

engine
to
warm

up

rapidlY
and
also

regulates
the

temperature
of
the
coolant
When

the
wax

pellet
in
the
thermostat
is
heated
it

expands
and
exerts

pressure
against
a
rubber

diaphragm
causing
the
valve
to

open

and
allow
the
coolant
to
flow
from
the

cylinder
head
back
to

the
radiator

As
the

pellet
is

cooled
itcontractsand
allows
the

spring
to

close
the
valve

thereby
preventing
coolant
from

leaving
the

cylinder
head

The
rad
ator
is
of
the
down

flow
type
with
an

expansion

tank
The
relIef
valve
in
the
radiator
filler

cap
controls
the

pressure
at

approximately
0
9

kg
sq
cm

l3Ib
sq
in
Always

try
to
avoid

removing
the
filler

cap
when
the

engine
is
hot
as

coolant

may
spray
out
and
cause

scalding

If
the

cap
must
be
removed
in
these
circumstances
use
a

lar
e

pic
c
of
cloth
to
hold
the

cap
and
turn

the
cap
sli

htlY

Walt
until
all

pressure
has

been
released
before

lifting
off
the

cap

F
AN
BELT
TENSION

The
fan
belt
drives
the
water

pump
and
alternator
as

well

as

the
fan
and
its
correct

adjustment
is
most

essential
A
loose

fan

belt
will

sl
ip
and

Y
e
r

and
most

probably
cause

overheating

alternatively
If
the
belt
IS
too

tight
the
pump
and
alternator

bearings
will
be
overloaded

The
belt
is

correctly
tensioned
if
it
can
be
depressed

by

approximately
10
mm

1
2
in
at
a

point
midway
between
the

fan
and
alternator
pulleys
See

Fig
R2

If

adjustment
is
neces

ary
slacken
the
alternator

mounting

and

adjustment
bolts
and

pivot
the
alternator

away
from
the

engine
to

tighten
the
belt
to

towards
the

engine
if

the
belt

is

to
be
slackened

NOTE

Always
apply
leverage
to
the
drive
end

housing
when

pivoting
the
alternator
and
never
to
the
diode
end

housing
or
the
alternator
will
be

damaged
Retighten
the
alternator
bolts
and
make
SUfe

that
the
belt

is

correctly
tensioned

FLUSHING
AND
DRAINING
THE
SYSTEM

The
radiator
and
water

passages
should
be
flushed
out

periodically
to
remove
the
accumulated
scale
or
sediment

Reverse

flushing
equipment
should
be
used
to

carry
out
a

completely
thorough
flushing
operation
but
the
owner
drivef

not

possessing
this

type
of

equipment
can
flush
out
the

system

in

the
following
manner

Drain
the
system
by
removing
the
radiator
filler

cap
and

opening
the
radiator
and

cylinder
block
drain

taps
Close
the

taps
again
and
refill
the
radiator
Run

the
engine
for
a
ShOft

period
and
then
rc
open

the
drain
taps
Continue
this

sequence

until
the
water

flowing
from
the

taps
is
clean
then
close
the

taps

and
refill
the
radiator

An
anti
freeze
mixture
should

always
be
used
in
Winter

time
The
Niss3n

long
life
coolant
L
L
c
is
an

ethylene
glycol

solution

containing
a
corrosion

preventative
which
can
remain

in
the
vehicle

throughout
the
year
but
must
not

be
mixed
with

other

products

It
is
advisable
to
check
the
radiator
and
heater
hoses
when

filling
with
anti
freeze
and
renew

them
if

signs
of
deterioration

are

apparent

WATER
PUMP

Replacement

The
water
pump
must
not
be
dismantled
and
should
be

renewed
if
it
becomes

faulty
The

pump
can
be
removed
in
the

following
manner

Drain
the

cooling
system

2
Take
the
fan
belt
off

the
pulley

3
Remove
the
fan
and

pulley

4
Remove

the
retaining
nuts
and
withdraw
the
water

pump

See

Fig
B
3

lnstallation
of

the

pump
is
a

reversal
of
the
removal

procedures

rERMOST
ATTesting

The
thermostat
is
located
in
the
water
outlet

passage

See

Fig
B
4
To
remove
the
unit
drain
the
cooling

system

remove
the
radiator
hose
and
the
water
outlet
elbow
Take
out

the
thermostat

25

The
thermostat
can
be

tested

by
suspending
it
with
a

thermometer
in
a

container
ftlled
with
water

Heat
the
water

gradually
and
stir
it
to

obtain
a
uniform

temperature
Maintain

a
constant

check
of
the

temperature
and

make
sure

that
neither
the
thermostat

or
thermometer

touch

the
sides
of
the
container
or
false

readings
will
be
obtained

The
thermostat
should

begin
to

open
at
a

temperature
of

820C

1
50C

179
60F
2

70Fj
and
should
be

fully

open

with
a
maximum
valve
lift
of
8
mm

0
315
in
at
a

temperature

of

950C
2030F

When

installing
the
thermostat

apply
adhesive
to

both
sides

of
the

gasket
before

refitting
the
water
outlet
elbow

RADIATOR
Removal

Drain

the

cooling

system
as

previously
described
and
remove

the
front

grille

2
Disconnect

the
radiator

upper
hose
lower

hose
and
hose
to

the
reservoir
tank

3
Remove
the

radiator

securing
bolts

and
lift
out
the

radiator

Fig
B
4
It
should
be
noted
that
cars
fitted

with
automatic
transmission

incorporate
a
transmission
oil
cooler

which
must

be
disconnected

Installation

is
a

reversal
of
the
removal

procedure
refill

the

system
as

previously
described

FLUID
COUPLING

The
water

pump
is

equipped
with

a
fluid

coupling
on

vehicles
fitted
with
an

air
conditioner

The
fluid

coupling

Limits

the
maximum
fan

speed
to

approximately
3000

r

p
ro

and
eliminates
noise

and
loss
of

power
at

high
engine

speeds

A
fault
in
the

coupling
may
be
caused

by
the

entry
of

foreign
matter

If
a
fault

developes
the

oupling
must
be

removed
and
dismantled

and
the
interior
cleaned

by

washing

in
solvent
The
condition
of
the
seal

and

bearing
must
be
care

fully
checked

and
the

coupling
replaced
if
the
latter

items
have

become
blackened
If
oil
leaks
occur

it
will
be

necessary
to

replace
the

water

pump
assembly
with
the

coupling
After

cleaning
the
unit
refill

with
11
5
cc
silicon
oil

using
a

suitable

syringe

TechnIcal

Data

Radiator

Radiator

cap
working
pressure

Radiator
core

heightxwidth

x

thickness

1400

and
1600
cc

engines
510

body

1600
and
1800
cc

engines
610

body
Corrugated
fin

type

0
9

kg

sq
cm

13Ib
sq
in

280x488x38mm

I
LOx
19
2x
1
49

in

360x502x32mm

l4
2x19

8x1
26
in

Thermostat

valve

opening

temperature

Standard

B20C
l
BOOF

Cold
climates
880C

1900F

Tropical
climates

76
50C
l700F

Max
valve
lift

Cooling
system

capacity

With

heater

Without
heater

Cooling
system

capacity

With

heater
Above
8
mm
0
31
in

6
8litres

1
75
US

gall

1
5

Imp
gall

6
4litres

1
75
US

gall

1
375

Imp
gall

1600

and
1800
cc

engines
610

body

6
5litres
l
7

US

gall

1
375

Imp
gall

6
0

Iitres
1
625
US

gall

1
375

Imp

gall
Without
heater

27

IgnItIon
System

DESCRII
TION

IGNITION
TIMING

IGNITION
DISTRIBUTOR
Maintenance

ADJUSTING
THE
CONTACT
BREAKER
GAP

CENTRIFUGAL
ADVANCE
MECHANISM

VACUUM
ADVANCE
MECHANISM

IGNITION
DISTRIBUTOR
Removal
and

Dismantling

IGNITION
DISTRIBUTOR

Assembling
and
Installation

SPARKING

PLUGS

DESCRII
TION

The

ignition
circuit

comprises
the
distributor

ignition
coil

ignition
switch

spark
plugs
high
tension
lead
and
the

battery

See
Fig
C
1

The
Hitachi
distributor
is
shown
in

exploded
form
in

Fig

C
2

19niton

timing
is

automatically
regulated
by
the
distributor

centrifugal
advance
mechanism
or
vacuum
advance
mechanism

depending
upon
the

demand
made
on

the
engine

The
vacuum
advance
mechanism

operates
under
part

throttle

only
and
uses
intake
manifold

depression
to
advance
the

ignition
timing
When
the

engine
speed
is
increased
the
vacuum

is

inoperative
and
ignition
timing
is

regulated
by
the

centrifugal

advance
mechanism

The

centrifugal
advance
mechanism
uses
a

system
of

governor
weights
and

springs
which
turn
the
carn

assembly
in
on

anti
clockwise
direction
to

advance
the

ignition
timing
As
the

engine
speed
is
decreased
the

weights
move
back
and
allow
the

cam
to
return

thereby
retarding
the

ignition
timing

The

ignition
coil
is
an
oil
filled
unit

comprising
a
coil

around
which
is
wound
the

secondary
and

primary
windings
The

number
of
turns
in
the

primary
winding
provide
a

high
secondary

voltage
throughout
the

speed
range
The
resistor
is
automatically

by
passed
at
the
moment
of

starting
and
allows
the

ignition

coil
to

be

directly
connected
to

the

battery
This
applies
the

full

battery
voltage
to
the

coil
to

give
the

necessary
staTting

boost

When
the
starter
switch
is
released
the
current
flows
through

the
resistor
and
the

voltage
through
the
coil
is

dropped
for

normal

running
purposes

IGNITION
TIMING

The

ignition
timing
can

be

accurately
checked

using
a

stroboscopic
timing
light
which
should
be
connected
in
accor

dance
with
the
manufacturers
instructions

Make
sure
that
the

timing
marks
on
the
crankshaft

pulley

are
visible
if

they
are
not
visible
mark

them
with
chalk

or

white

paint
Each
mark

represents
a
50
division
of
the
crank

angle

Disconnect
the
distributor
vacuum

line
start

the

engine

and
allow
it
to
run
at
normal

idling
speed
or

slightly
below

Point
the

timing
light
at
the

timing
pointer
on
the
front
cover

Fig
C
3
The
crankshaft

pulley
groove
should

appear

to

be

stationery
and

aligned
with
the

pointer
on
the
front
cover

The

top
dead
centre
mark
is
located
at
the
extreme

right
as

shown
in
the
illustration
If
the

setting
requires
adjustment
the

distributor

flange
bolts
must
be
slackened
and
the
distributor

body
turned
clockwise
to
advance
or
anti
clockwise
to
retard

the

timing
See
Technical
Data
for

timing
settings

After

adjusting
the

timing
tighten
the
distributor

flange

bolts
and
recheck
the

timing

IGNITION
DISTRIBUTOR
Maintenance

Remove
the
distributor

cap
by
easing
away
the
two

clamps

and
examine
the

points
for

signs
of

burning
or

pitting
The

points
can
be
cleaned
if

necessary
using
a
fine

grade
of
oilstone

or
file
The
faces
of
the

points
must
be

completely
flat
and

parallel
and
all
abrasive
dust
removed
with

compressed
air
If

the

points
are

excessively
pitted
they
must

be
renewed
and

grease

applied
to
the

moving
contact

pivot
and
the
surface
of

the
cam

Ensure
that
the
distributor

cap
is

thoroughly
clean
both
inside

and
outside
A

contaminated

cap
will

promote
tracking

indicated

by
black
lines
and
caused

by
electrical

leakage
between

the

segments
on
the
inside
of

the

cap
Make
sure
that
the

carbon

button
is
not
worn
Both
the
distributor

cap
and
rotor

must
be
renewed
if

they
are
cracked
or

damaged

IGNITION
DISTRIBUTOR

Adjusting
the
contact

breaker

gap

To

adjust
the
contact
breaker

points
remove
the
distributor

cap
and

pull
the
rotor
off

the
cam

spindle

Turn
the

engine
until

the
heel
of
the
contact
breaker
arm

is

positioned
on
the
cam

lobe
the
contact

breaker

gap
is
set
to

the
maximum
in
this

position

Slacken
the

adjusting
screw

Fig
CA
insert
a
feeler

gauge

between
the

points
and

adjust
the
breaker

plate
until
the
re

quired
gap
of
0
45
0
55
mm
0
0177
0
0217
in

is
obtained

Tighten
the

adjusting
screw
and
recheck
the

setting
After

the
contact
breaker

gap
has
been

adjusted
check
the

ignition

timing
as

previously
described

The
tension
of
the
contact
breaker
should
be
0
5
0
65

kg

I
I
I
4
lb
Measure
the
tension
with
a

gauge
and
at
900
to

the
contact
breaker
arm

29

CENTRIFUGAL
ADVANCE
MECHANISM

Special
equipment
is

required
to
check
the
advance

characteristics
It
is

possible
however
to

carry
out
an
exam

ination
of

the
caffi

assembly
and
the

weights
and

springs
to

ensure
that
the
earn
is
not

seizing

Lift
off
the
distributor

cap
and
turn
the
rotor
anti
clock

wise
When

the
rotor

is
released
is
should
return
to

the
fully

retarded

position
without

sticking
If
it

does
not
return
to
the

fully
retarded

position
it
will
be

necessary
to
check
for

dirt

and
weak

springs

It
should
be
noted
that

any
wear
in
the

mechanism
or

lose
of

spring
tension
will

upset
the
advance
characteristics
and

cause

unsatisfactory
engine
running
performance
over
the

speed

range

VACUUM
ADVANCE
MECHANISM

The

diaphragm
of
the
vacuum
advance

mechanism
is

mechanically
connected
to
the
contact
breaker

plate
The
rise

and
fall
of
inlet
manifold

depression
causes

the

diaphragm
to

move

the
contact
breaker

plate
to

advance
or

retard
the

ignition

If
the
vacuum

control
unit
fails
to

function

correctly
a

check
can
be
carried
out
to
ensure
that
the
contact
breaker

plate

is

moving
freely
and
that
the

three
steel

balls
at

the

top
and

oottom
of
the

plate
are

adequately
lubricated

Also
make
sure
that
the
vacuum
inlet

pipe
is
not
blocked

or

leaking
and
is

securely
tightened

Leakage
may
be
due
to
a

defective

diaphragm
which

should

be
renewed

along
with

any
other

faulty
part
of
the
mechanism

IGNITION
DlSTRffiUTOR
Removal

and

Dismantling

Disconnect
the

battery
leads

2
Disconnect
the

high
tension
lead
at

the
coil

3
Withdraw

the
high
tension
leads
from
the
distributor

cap

4
Detach
the
suction

pipe
from
the
vacuum
control
unit

5
Mark
the

position
of
the
distributor
and
rotor
remove
the

flange
mounting
bolts

and
withdraw
the
distributor

To
dismantle
the
distributor

proceed
as

follows

Take
off
the
distributor

cap
and
remove

the
rotor

Slacken

the
two
set
screws

holding
the
contact
breaker

upper
plate

Remove
the

primary
cable
terminals
and
withdraw
the
contact

set
from

the
distributor
Fig
C
S
Remove
the
vacuum
control

unit

c
Remove
the
two
screws
and
lift
out
the
contact

breaker

plate
detach
the

clamp
the
terminal
and
the
lead

To
remove
the
cam
take
out
the
centre
screw
as

shown
in

Fig
e
6
Drive
out

the
drive

pinion
retaining
pin
with
a
drift

and
hammer
Fig
e
and
remove
the

pinion
and
washer
Take

care
not
to
stretch
or
deform
the

governor
springs
when

detaching

them
from
the

weights

IGNITION
DISTRIBUTOR

Assembling
and

Installing

Assembly
is
a
reversal
of
the

dismantling
procedure

Lubricate
the

moving
contact

pivot
and
smear
the
lobes
of
the

cam
with
multi

purpose
grease

If

the
centrifugal
advance
mechanism
has
been
dismantled

the

governor
springs
and
cams
must
be
refitted
as

shown
in

Fig
e
8
The

governor
weight

pin
6
should
be
fitted
into

the

longer
of
the
two
slots

leaving
a
certain
amount
of

clearance

for
the
start

and
end
of
the

centrifugal
advance
movement

When

installing
the
distributor
take
care
to

align
the

body

and
rotor

with
the
marks
made
during
removal
The
rotor
must

be

positioned
in
its

original
location
it
will
turn

slightly
when

the
distributor
is
inserted
and
the

gear
teeth
mesh
Remove
and

replace
the
distributor
if

the
rotor
does
not

point
to
the

align

ment

mark
until
both
distributor

body
and
rotor
are
correctly

aligned

SPARKING
PLUGS

The

sparking
plugs
should
be

inspected
and
cleaned
at

regular
intervals
not

exceeding

every
10
000
km
6000
miles

New

sparking
plugs
should
be
fitted
at

approximately
20
000

km
12
000
miles

Remove
the

plugs
and
check
the
amount
of
electrode

wear
and

type
of

deposits
Brown
to

greyish
tan

deposits
with

slight
electrode
wear

indicate
that
the

plugs
are

satisfactory
and

working
in

the
correct
heat

range

Dry
fluffy
carbon

deposits
are
caused

by
too

rich
a
mixture

dirty
air
cleaner
excessive
idling
or

faulty
ignition
In
this

case

it
is
advisable
to

replace
the

plugs
with

plugs
having
a

higher
heat

range
Oily
wet
black

deposits
are
an

indication

of

oil
in

the
combustion
chambers

through
worn

pistons
and

rings
or
excessive
clearance
between
valve

guides
and
stems

The

engine
should
be
overhauled
and
hotter

plugs
installed
A

white
or

light
grey
centre

electrode
and
bluish
burned
side

electrode
indicates

engine
overheating
incorrect

ignition
timing

loose

plugs
low
fuel

pump
pressure
or
incorrect

grade
of
fuel

Colder

sparking
plugs
should
be
fitted

The

plugs
should
be
cleaned
on
a

blasting
machine
and

tested
Dress
the
electrodes
with
a
small
file
so
that
the
surfaces

of
both
electrodes
are
flat
and

parallel
Adjust
the
spark
plug

gap
to
0
8
0
9
mm
0
031
0
035
in

by
bending
the
earth

electrode
Refit
the

plugs
and

tighten
them
to
a

torque
reading

of
1
5
2
5

kgm
II
15Ib
ft

31

Fuel

System

DESCRIPTION

FUEL
TANK

FUEL
PUMP

CARBURETTOR
IDLING
ADJUSTMENT

FAST
IDLE
OPENING
ADJUSTMENT

THROTTLE
VALVES
INTERLOCK
OPENING

DASHPOT

DESCRIPTION

The

diaphragm
type
fuel

pump
shown
in

Fig
D
1
feeds

fuel

from
the
tank
to
the
carburettor
in
a

regulated
supply

according
to
the
needs
of
the

engine
A
cartridge
type
fuel

strainer

prevents
any
dirt
from

reaching
the

pump
inlet
valve

The

carburettor
fitted
to

the

engine
is
either
a
down

draught
two
barrel

type
equipped
with
a
throttle

operated

acceleration

pump
and
power
valve
mechanism

See
Fig
D
2

or
a
twin
SU
carburettor
of
the

type
shown
in

Fig
D
3
In
the

two
barrel

type
carburettor

fuel
flows
from
the

passage
at
the

bottom
of
the
float
chamber

passes
through
the

primary
main

jet
and
mixes
with
air

introduced

through
the
main
air
bleed

screw

The

petrol
and
air
mixture
is

injected
into
the
venturi

through
the
main
nozzle

Each
time
the
accelerator

pedal
is

depressed
the
throttle

opens
and
the
accelerator

pump
forces
a

jet
of

petrol
into
the

air
stream
to
allow
the

engine
to
accelerate

smoothly
See

Fig

0
4
The

power
valve
mechanism
is

operated
automatically

according
to
the
demands
made

by
the

engine
Under
light
load

i
e

part
throttle
conditions
the
intake
manifold

depression
is

transmitted
below
the
throttle
valve
the
vacuum

pulls
a

piston

upwards
against
a

spring
and
leaves
the

power
valve
closed

allowing
additional
air
to
be

admitted
through
the
air
bleed
screw

and
thereby
weaken
the

petrol
and
air
mixture
When
the
vacuum

below
the
throttle
vaJve
is
lowered

during
full
load
conditions

the

piston
is

pushed
down
opening
the

power
valve
and
providing

additional
fuel
to
enrichen
the
mixture

The
model

HJ
L
38W6
SU
twin
carburettor
is
of

the

horizontal
variable
venturi

type
and
is
used

only
on
the
1600

and
1800
cc

engines
In
this

type
of
carburettor
a

constant

flow
of
intake
air
is

maintained

by
the

automatically
adjusted

venturi

opening
this
is
accomplished

by
the
suction

piston

sliding
in
accordance
with

changes
in
the
volume
of
intake
air

Referring
to

Fig
D
5
the
suction
chamber
is
mounted
above

the
venturi
The
suction

piston
slides
vertically
within
the

chamber

and

changes
the
venturi

opening
area
The

piston
is

operated
by
a

difference
between
the

upper
vacuum

pressure

which
is

applied
through
the
suction

poct
and
the
atmospheric

pressure
which

is
introduced

through
the
air
hole
from
the
air

cleaner

The
amount

by
which
the
throttle
is

opened
causes
the

suction

piston
to
rise
or
fall
under
the
intluence
of
the

engine

suction
The

pozzle

opening
therefore

changes
and

provides
an

optimum
air
fuel
mixture
at
all

engine
speeds

The

cartridge
type
fuel
strainer
utilizes
a
fibre
strainer

element
which
should
be

replaced
every
20
000
km
12
000

miles
Removal
of
the
fuel
strainer
is
a

simple
operation
but
as

it
cannot
be
drained
the
strainer
should
not
be
removed
when
CARBURETIOR
Removal
and
Overhaul

FLOAT
LEVEL
Adjustment

SU
TWIN
CARBURmORS

Adjustments

SU
TWIN
CARBURmORS

Dismantling

SU
TWIN
CARBURETTORS

Inspection

STARTING
INTERLOCK
VALVE
OPENING

HYDRAULIC
DAMPER

the
tank
is

full
unless

absolutely
necessary

A

viscous

paper
type
air
cleaner
element
is
fitted
which

does
not

require
cleaning
and
should
be

repl
ced

every
40
000
km

24
000
miles
The
air

cleaner
fitted
on
the

single
carburettor

is
equipped
with
an

idling
compensator
to

prevent
the
mixture

from

becoming
too

rich
at

high
idling

temperatures
Additional

fresh
air
is
introduced
into
the
inlet
manifold

by
the
action
of

a
bimettalic

strip
located
in
the
air
cleaner
When
the

temperature

under
the
bonnet
is

high
the
bimetal
is

heated

by
the
hot
inlet

air
and
lifts
to
allow
the
valve
to

open
The

idling
compensator

valve

partially
opens
at

550
I310F
and
is

fully
open
at

650C

l490F
The
unit
cannot
be
dismantled
as

it
is

pre
sealed
and

correctly
adjusted
for
valve

timing
Fig
D
6
shows
the

layout

of

the
idling
compensator
piping

FUEL
TANK

Replacing

The
fuel
tank
can
be
removed
in
the
following
manner

Remove
the
rear
seat

and
back
rest

2
Take
out
the
board
behind
the
back
rest

3
Take
out
the

luggage
compartment
lining
board
and

disconnect
the
cable
to
the

petrol
gauge
unit

4
Disconnect
the
petrol
filler
tube
from
the
tank

5
Remove
the
tank
retaining
bolts
and
disconnect
the

rubber
fuel
outlet
and
return
hoses

Installation
is

a
reversal
of
the
removal

procedure
always

ensure
that
the
fuel
lines
arc
carefully
checked
for

signs
of

damage
before

replacing
the
tank

FUEL
PUMP

Testing

Pressure
and
capacity
tests
can
be
carried
out
with
the

pump
installed
in
the

following
manner

Static

pressure
test

Disconnect
the
fuel
line
at

the
carburettor
install
an

adaptor
tee

fitting
and
suitable

pressure
gauge
to
the
fuel
line

between
carburettor
and
fuel

pump
Start
the
engine
and
run
it

at

varying
speeds

The

reading
on

the
gauge
should
be
0
18
0
24

kg
sq

cm
2
6
34
Ib

sq
in
If
the

pressure
is
below
the

specified

figure
then
either
one

part
of
the

pump
has
worn

excessively

or

general
wear
has
occured
to

all
the

working
parts
The
faults

may
include
a

ruptured
diaphragm
worn
and

warped
valves

33

and
seats
or
a
weak

diaphragm
return

spring

A

pressure
above
the

specified
figure
may
be
due
to

an

excessively
strong
and
tight
diaphragm

Capacity
test

The

capacity
test
can
be

carried
out
when
the
static

pressure
has
been
tested
and
conforms
with
the

specified
figure

of
0
18

kg
sq
cm
2
6Ib

sq
inJ

Disconnect
the
fuel
line
at

the
carburettor

and

place
a

container
under
the
end
of
the

pipe
to
act
as
a
fuel

sump

Start
the

engine
and
run
it
at
a

speed
of
1000

Lp
m
The

amount

of
fuel
delivered
from
the

pump
in
one
minutc
should

be

1000
cc
2
1
US

pt

If

petrol
does
not
flow
from
the

opcned
end
of

the
pipe

at
the
correct
rate
then
either
the
fuel

pipe
is

clogged
or

the

pump
is
not

operating
correctly

If
the
latter
cause
is

suspected
the

pump
must
be
removed

and

inspected
as
described
below

FUEL
PUMP

Removing
and

Dismantling

Before

removing
the
pump
take
off
the

petrol
tank

cap

and
disconnect
the

pump
inlet
and
outlet

pipes
Blow

through

the

pipes
with

compressed
air
to

make
sure

that

they
are
not

clogged

Remove
the

pump
retaining
nuts

withdraw
the

pump
and

dismantle
it
in
the

following
order

Referring
to

Fig
D
l

Take
out
the
screws

holding
the
two

body
halves

together

and

scparate
the

upper
body
from

the
lower

body

2
Remove
the

cap
and

cap
gasket

3
Unscrew
the
eI
bow
and
connector

4
Take
off

the
valve
retainer
and
remove
the
two
valves

5
To
remove
the

diaphragm
diaphragm
spring
and
lower

body
sealing
washer

press
the

diaphragm
down

against

the
force
of
the

spring
and
tilt
the

diaphragm
at
the
same

time
so
that
the

pull
rod
can
be
unhooked
from
the
rocker

arm

link

Fig
D
7

The
rocker
arm

pin
can

be
driven
out
with
a
suitable

drift

FUEL
PUMP

Inspection
and

Assembly

Check
the

uppcr
and

lower

body
halves
for
cracks

Inspect

the
valve
and
valve

spring
assembly
for

signs
of
wear
and
make

sure
that
the

diaphragm
is
not

holed
or

cracked
also
make
sure

that
the
rocker
arm
is
not
worn
at
the

point
of
contact
with

the

camshaft

The
rocker
arm

pin
may
cause

oil

leakage
if
worn

and

should
be
renewed
Assembly
is
a
reversal
of
the
dismantling
procedure

noting
the

following
points

Fit
new

gaskets
and
lubricate
the
rocker
arm
link
and
the

rocker
arm

pin
before

installing

The

pump
can
be
tested

by
holding
it
approximately
I

metre
3

feet
above

the
level
of
fuel

and
with
a

pipe
connected

between
the
pump
and
fuel
strainer

Operate
the
rocker
ann

by
hand
the

pump
is

operating

correctly
if
fuel
is
drawn

up
soon
after

the
rocker
ann
is

released

CARBURETTOR
IDLING
ADJUSTMENT

The

idling
speed
cannot
be

adjusted
satisfactorily
if
the

ignition
timing
is
incorrect

if
the
spark
plugs
are

dirty
or
if

the
valve
clearances
are
not

correctly
adjusted

Before

adjusting
the

idling
speed
set
the
hot
valve

clearances

t
o
0
25
mm
0
0098
in
for
the
intake
valves

and

0
30
mm
0
0118
in
for
the
exhaust
valves
as
described
in

the
ENGINE

section

Idling
adjustment
is
carried
out

with
the
throttle

stop

screw
in

conjunction
with
the

idling
adjustment
screw

See

Fig
D
8

Run
the

engine
until
it
attains
its
normal

operating

temperature
and
then
switch
off

Starting
from
the
fully
closed

position
unscrew
the

idling
adjustment
screw

by
approximately
three
turns

Screw
the
throttle

stop
screw
in

by
two
or
tftr
e
turns
and

start

th
engine

Unscrew
the
throttle

stop
screw
until
the

engine
commences

to
run

unevenly
then
screw
in
the

idling
adjustment
screw
so

that
the
engine
runs

smoothly
at
the

highest
speed

Readjust
the
throttle

stop
screw
to

drop
the

engine
speed

of

approximately
600
r

p
m
is
obtained

WARNING
Do
not

attempt
to
screw

the

idling
adjustment

screw

down
completely
or
the

tip
of
the
screw

may
be

damaged

FAST
IDLE
OPENING
ADJUSTMENT

The
choke
valve
is

synchronized
with
the
throttle
valve

and
connected
to
it

by
levers
as
shown
in

Fig
D
9
The
fast

idle
opening
can
be
check

by
fully
closing
the
choke
valve
and

measuring
the
clearance
between
the

primary
throttle
valve
and

the
wall
of

the
throttle
chamber
This
clearance

being
shown

as
A

in
the
illustration
The
clearance
for

the
carburettor

types
is
as
follows

Carburettor

type
Throttle

opening

angle

180

180

190
Dimension
A

213304
361

13304
4
I

13282
331
1
55mm
0
06lin

1
55mm
0
06Iin

1
3
mm
0
051
in

35

Carburettor

type
Throttle

opening

angle

190

200
Dimension
A

213282

341

213282
221
l
3mm
0
051
in

I
4mm
0
056in

If

adjustment
is

required
the
choke
connecting
rod
can
be

carefully
bent
until
the

required
clearance
is

obtained

THROTTLE
VALVES
INTERLOCK
OPENING
ADJUSfMENT

Open
the

primary
throttle
valve
500
from
the

fully
closed

position
as
shown
in

Fig
D
I
O
At

this

angle
the
connecting

link
2
should
be
at

the
extreme

right
of
the

groove
in

the

primary
throttle
arm
The

linkage
between
the

primary
and

the

secondary
throttles
is

operating
correctly
if
the
clearance

C
between
the

primary
throttle
valve
and
the
wall
of
the

chamber
is
as
follows

Carburettor

type

213304

361

213304
421

213282
331

213282
341
Dimension
C

6
3
mm
0
248
in

6
3
mm
0
248

in

74
mm
0
291
in

74
mm
0
291
in

Adjustment
can
be
made
if

necessary
by
bending
the

connecting
link
until
the

required
clearance
is
obtained

DASHPOT
ADJUSfMENT

This

adjustment
is

only
required
on

carburettors
fitted
to

vehicles
with
automatic
transmission
Correct
contact
must
be

made
between
the
throttle
lever
and
the

dashpot
stem
See

Fig
D
II

Adjustment
can

be
carried
out
if

necessary
by

slackening
the
locknut
2
and
then

rotating
the

dashpot
in

either
direction
so
that
the
throttle
ann
touches
the
stem
at
a

throttle
valve

opening
angle
of
110
At

this
angle
the
clearance

B
between
the
throttle
valve
and
the
wall
of
the
chamber

should
be
as
follows

Carburettor

type

213304
421

213282
341
Dimension
B

0
780mm
90
0307
in

0
586mm
0
0231
in

Retighten
the
locknut
after

completing
the

adjustment

CARBURETTOR
Removal
and
Overhaul

The
carburettor
can
be
removed
from
the

engine
in
the

following
manner

Remove
the
air
cleaner

assembly

2
Disconnect
the
fuel
and
vacuum

pipes
and
the
choke
wire

from
the
carburettor

3
Remove
the
throttle
lever
and
take
off
the
nuts
and

washers

securing
the
carburettor
to

the
manifold

4
Lift
the
carburettor

away
from
the
manifold
and
discard

the

gasket

To
dismantle
the
carburettor
for
a

complete
overhaul

remove
the

primary
and

secondary
main

jets
and
needle
valves
these
are
accessible
from
the
exterior
of
the
carburettor

Remove
the
choke

connecting
rod

pump
lever
return

spring
and
set
screws
and
take
off
the
choke
chamber

The

primary
and

secondary
emulsion
tubes
can
be
with

drawn
after

removing
the
main
air
bleed
screws

If
the
accelerator

pump
is
to
be
checked
take
off
the

pump

cover
but
take
care
not
to
lose
the
return

spring
and

inlet
valve

ball
situated
at
the
lower

part
of
the

piston

Separate
the
throttle
chamber
from
the
float
chamber

by

removing
the

retaining
screws
leave
the
throttle
valve

intact

unless
otherwise

required

All

parts
of
the
carburettor
must
be
ctifefully
cleaned
and

sediment

gum
or

other

deposits
removed

Clean
the

jets
by
blowing
through
them
with

compressed

air
Never

push
wire

through
the

j
ts
or

passages
or
the
orifices

will
be

enlarged
and
the
calibration
affected

Check
all

parts
for

signs
of
wear
and

exchange
them
if

necessary

Examine
the
float
needle
and
seat
for
wear

and
make
sure

that
the
throttle
and
choke
bores
in
the
throttle

body
and

cover
are
not
worn
or
out
of
round
If
the

idling
adjustment

needles
have
burrs
or

ridges
they
must

be
replaced

Inspect
the

gaskets
to
make
sure
that

they
are
not
hard

and
brittle
or
distorted

Oean
the
filter
screen
if
it
is

clogged
or

change
it
if
it

is

otherwist

unsatisfactory

Check
the

operation
of
the
accelerator

pump
by
pouring

petrol
into
the
float
chamber
and
operating
the
throttle
lever

Petrol
should

spurt
from
the

pump
discharge
jet
if

the

pump
is

working
correctly
If

petrol
cannot
be

ejected
from
the

jet

when
the
lever
is
actuated
clean
the
discharge
jet
by
blowing

through
it
with
compressed
air

CARBURETTOR
Assembly
and
Installation

The

assembly
and
installation
of
the
carburettor
is
a

reversal
of

the
dismantling
and
removal

procedures
noting
the

following
points

Always
replace
the

gaskets
if

they
are
not

satisfactory
and

take
care
that
the
carburettor

linkage
operates
smoothly
and
is

not
bent
or
distorted

The

performance
of
the
carburettor
will

depend
on

the

condition
of

the
jets
and
air
bleeds
As

previously
stated
these

pacts
should
be
cleaned

using
petrol
and

compressed
air

only

Replacement
jets
or
air
bleed
screws
can

be
used
to

provide

greater
economy
or
to
increase

output
whatever
the
require

ment
When

the
carburettor
is
installed

adjust
the
idling
speed

as

previously
described

37