oil DATSUN 610 1969 User Guide

liB
Oversizes

Ring

groove
width

Top
ring

Second

ring

Oil

ring

Piston
to
bore

clearanl
e

Pin
diameter

I
ength

Ll4
Ll6

Ll8

Pin
to

piston
clearance

Pin
interference
fit
in
small
end
bush

Piston

ring
height

Top

Second

Side
clearance

Ll4
Ll6

Top
ring

LI8

Top

ring

Second

ring

Ring

gap

U4

Top
ring

U4
Second

ring

Ll6

Top
ring

L
16
Second

ring

U8

Top
ring

U8
Second

ring

Oil

ring

Oil

pump

Oearance
between
inner

and
outer
rotor

Rotor

tip
clearance

Oearance
between
outer
rotor

and

body

Rotor
to

bottom
cover

clearance

Oil

pressure
at

idling

Oil

pressure
relief
valve

spring

Free
length

Fitted

length

Relief
valve

opening

pressure

24
85465485
515
mm
3
648
667
ill

86
065
86
015
mm

13
3844
33864
in

0
mm
CO
0787

in

0
mm
0
0787
in

4
0
mm
0
1
q
c
in

0
025
0
045
mm
0
0010
0
0018
in

PISTON
PIN

20
995
1
000
mm

0
8266

0
8168
in

72
00

72
25

0
001

0
Dl5
72
25
mm

2
8346
2
8445
in

73
00
mm

2
8445

2
8740
in

0
013
mm
0
00004
0
00051
in

0

033
mm
0
0006
0
0013
in

PISTON

RING

1
977
mm
0
0778

in

1
977
mm
0
0778
in

0
040
0
080
mm
0
0016
0
0031
in

0
045
0
080
mm

0
0018
0
0031
in

0
030
0
070
mm
0
0012
0
0028
in

0
23
0
38
mm
0
0091

0
0150

in

0
15
0
30
mm
0
0059
0
0118
in

0
25
0
40
mm
0

0098
0
0157
in

0
15
0
30
mm
0
0059
0
0118
in

0
35
0

55
mm
0
0138
0
0217
in

0
30
0
50mm
0
0118
0
0197
in

0
30
0

90
mm
0
0118
0
0354
in

LUBRICATION

SYSTEM

Rotor

Pump

0
05
0
12
mm
0

0020
0
0047

in

less
than
0
12
mm
0
0047
in

0
15
0
21
mm
0
0059
0
0083
in

0
03
0

13
mm
0
0012
0
0051
in

0
8
2
8

kg
sq
cm
11
40
Ib

sq
ln

52
5
mm

2
067
in

34
8
mm

1
370
in

3
5
5
0

kg
sq
cm

50
71
Ib

sq
ln

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

inter
lW
j

@lPX

TT
Y

Gw

PRIMARY
COIL

RESISTOR

I
I

l1@

l
I

IGNITION
U

SECONDARY

COIL
COIL

IS
AK
R
POIN

i

1
1

DISTRISUTOR

I

1
J

ISI
V

nl
N

I

TO
STARTER

l

1
ROTOR
HEAD

r
SPARK
PLUG

Fig
C
t

Ignition
sys
em
circuit

diagram

i
II

@

1
1

@

J

i
9

28

l

I
i
1

I

I

@

@

G
N

7

Fig
C

2lgnition
distributor

1

Shaft
assembly

2
Collar

assembly

3
Cam
assembly

4
Governor

weights

5
Governor
spring

6
Rowr

head

7

Breaker
plate
8
Contact
set

9
Tennirtal

assembly

10
Vacuum
control

J
1
Condenser

12

Distributor
cap

13
Carbon

point

14
Plate

15

CIilmp

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

TechnIcal
Data

IGNITION
DISTRIBUTOR

Type

L16
ll8
with

single
carbl

L16
L18
with
twin
arb

L14

Firing
order

Rotation

Ignition
timing
BTDC

0411
58K

0409
54K

0411
63

Dwen

angle
Hitachi
D411
58K

Hitachi
D409
54
K

Hitachi
0411
63

I
3
4

2

anticlockwise

100
at
600
r

p
m

140
at
650
c

p
m

80
at
600
r

p
m

49
550

Contact

point

gap
setting

Contact

spring
tension
0
45
0
55
mm
O
OI77
0
0217
in

0
50
0
65

kg
l
l
0
I
43
lb

Condenser

capacity
0
22
0
44
F

IGNITION
COil

Type

Spark
plugs

With

single
carb

With
twin
carb

Plug

gap

Tightening
torque
Hitachi
6
R
200

NGK
BP
5ES

NGK
BP
6ES

0
8
0
9
mm
0
031
0
035
in

1
5
2
5

kgm
II
15Ib
ft

1300cc

engine
IGNITION
TIMING

Adjustment

100
B
T
D
C
600
r

p
m

32

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

inter
ill
j

@
pl

T
i

5

12

Fig
D
3

View
of
the
SU
twin

type
carburettors

1

Throttle
r

2
JaJana

crew

Front
throttle

adjusting
screw

4

AuxiliDry
shoft

5
Ftnt
idle

selling
lCn
W

6

Throttle

shaft

7
Rear
throttle

adjusrint
screw

8

Idling
adjustment
nuts

m

11

j
G

36
B

l
D

i
I

lli

9
3
J6

6

Fig
D
4

Accelerator

pump
mechanism

J

Pump
injuror

2

Weight

2
Outklvolve

4
Piston

5

Damper
spring

6
Piston

return

spring

7

Clip

8
Strainu

9
Inlet
lmlJe

I

Fig
D
6

Idling
compensator
1

lit

21
Fig
D
5
Section

through
the
SU
twin
carbureUor

J
Suction

chamber

Suctiull

spring

3
Hoat

chamber
corer

4
Guide

5

Nipple

6
Throttle
chamber

7
Piston
rod

8

Needle
valve

9
T7trollle
l
ob
e

J
O
Float
chtzmber

J
1
Float
Iel
cr
J
2
Float

13
Sleel
e

4

aip

5
Fuel
hose

6
Oil

cap
nut

1
7

Plunger
rod

18
Transvtne
hole

J
9
Oil

domJX

20
Suction

piston

21
Nozzle

Idling
adjustment
nut

FLOAT
LEVEL

Adjustment

A
constant
fuel

level
in
the
float

chamber
is
maintained

by

the
float
and
ball
valve

Fig
D
12
If
the
fuel
level
is
not

in

accordance
with
the
level

gauge
line
it
will
be

necessary
to
care

fully
bend

the
float
seat
until
the
float

upper
position
is

correctly

set

Fig
D
13

The
clearance
H
between
the
valve
stem

and
float
seat

should
be
1
0
mm
0
039
in
with
the
float

fully
lifted
as
shown

Adjustment
can

be
carried
out

by
carefully
bending
the
float

stopper
Fig
D
14
until
the

required
clearance
is
obtained

SU
TWIN
CARBURETTORS

Adjustments

It
is
essential
that
the
two

carburettors
are

correctly
adjusted

if

peak
m3l1ce
and
economical
fuel

consumption
is
to
be

realized
Incorrect
carburettor

a
ljustment
will
have
an
adverse

affect

during
idling
and
on

acceleration
etc

Carburettor

synchronization
and

idling
adjustment

Run
the

engine
until
it
reaches
its
normal

operating

temperature
remove
the
air
cleaner
and
slacken

the
front

and

rear
throttle

adjusting
screws
the
balance
screw
and
the
fast

idling
setting
screw
Make
sure
that
the
front
and
rear
throttle

shafts
are
not
connected

Fully
tighten
the

idling
adjustment

nuts
of

the
front

and
rear

carburettors

Fig
D
15

the
back

off
each
nut

by
an

equal
amount
and

by
one
and
a
half
to
two

tUrns

Screw
in
the
front
and
rear
throttle

adjusting
screws

by
a

few
turns
and
start
the

engine
Allow
the

engine
to
reach
its

normal

operating
temperature
before

proceding
to

the
next

stage

Adjust
the
front
and
rear
throttle

adjusting
screws
until

the

engine
speed
is
reduced
to

approximately
600
700
r

p
m

The

engine
should
turn
over

smoothly
and

consistently
Apply

a

flow
meter
to
the
front
carburettor
air
cleaner

flange
and
turn

the

adjustment
screw
on
the
flow
meter
so
that
the

upper
end

of
the
float
in
the

glass
tube
is
in

line
with
the
scale
Uft
off
the

flow
meter

and
apply
it
to

the
rear
carburettor
air
cleaner

flange

without

altering
the

setting
of
the
flow
meter

adjusting
screw

If

the

position
of
the
flow

meter
float
is
not

aligned
with
the

scale

adjust
the
rear
carburettor

throttle
adjusting
screw
to

align
the
float
with
the
mark
on
the
scale

With
the
carburettor
flow

correctly
adjusted
turn
the

idling
adjustment
nuts

of
both
carburettors

approximately
1
8

of

a
turn

either
way
to
obtain

a
fast

and
stable

engine
speed

Both
nuts
must

be
turned

by
an

equal
amount

Back
off
the
front
and
rear
throttle

adjusting
screws
and

adjust
the

engine
speed
to

the

specified
value
of

650
r

p
m

for

the
standard

engine
or
700
r

p
m
with
vehicles
fitted
with

automatic
transmission
Make
sure

that
the
air
flow
of

both

carburettors
remains

unchanged
Screw
in
the
balance
screw

until
the
screw
head
contacts
the

throttle
shafts
without

changing
the

idling

speed
setting

Move
the
throttle

connecting
shaft
and
accelerate
the

engine
a
few
times
then
check
that
the

idling
speed
is

unchanged

Turn
the
fast
idle

setting
screw

to
increase
the

engine
speed

to

approximately
1500

r

p
m
and
recheck
with
the
flow
meter
that
the
air
flow
for
both
carburettors
is

correctly
matched
If

the
air
flow
is
uneven

it
will
be

necessary
to

readjust
the
balance

screw

Finally
back
off

the
fast
idle

setting
screw

Fig
D
16

and
decrease
the

engine
speed
Apply
the
flow
meter
to

the

carburettors
to
confirm
that
the
float

positions
are
even
Re

adjust
if

necessary
by
means
of

the
throttle

adjusting
screws

Stop
the

engine
and
fit
the
air
cleaner

SU
TWIN
CARBURETTOR

Dismantling

Piston
and
suction
chamber

Dismantling

Unscrew
the
plug
and
withdraw
the

piston
damper
Fig
D

17
Remove
the
four
set
screws

and
lift
out

the
suction

chamber
withdraw
the

spring
nylon
washer
and
the

piston

Take
care
not
the

damage
the

jet
needle
and
the
interior
of

the

suction
chamber

Do
not
remove
the

jet
needle
from
the

piston
unless

absolutely
necessary
If
a

replacement
is
to
be
fitted
ensure
that

the
shoulder
of
the
needle
is
flush
with
the
lower
face
of

the

piston
This

operation
can

be
accomplished
by
holding
a
strai

edge
over
the
shoulder
of
the
needle
and
then

tightening
the

set
screw
as
shown
in
Fig
D
18

Wash
the
suction
chamber
and

piston
with
dean
solvent

and

dry
with

compressed
air
Lubricate
the
piston
rod
with
a

light
oil
Do

NOT
lubricate
the

large
end
of
the

piston
or
the

interior
of
the
suction
chamber

NOZZLE

Dismantling

The
nozzle
See
Fig
D
19
can
be
removed

quite
easily

but
should
not
be
dismantled
unless

absolutely
necessary
as

reassembly
of

the
nozzle
sleeve
washer
and
nozzle
sleeve

set
screw
is
an

extremely
intricate

operation

To
remove
the
nozzle
detach
the

connecting
plate
from

the
nozzle
head

pulling
lightly
on

the
starter
lever
to
ease
the

operation
Loosen
the

retaining
clip
take
off
the
fuel
line
and

remove
the
nozzle
Be
careful
not
to

damage
either
the
jet

needle
oc

the
nozzle
Remove
the
idle

adjusting
nut
and

spring

The
nozzle
sleeve
can
be
removed
if

necessary
by
taking
out

the
set
screw
but
as
previously
stated
should
not
be
dismantled

unless

absolutely
necessary

SU
TWIN
CARBUREfTOR

Assembly

Assemble
the

piston
assembly
into

position
but
do
not

fill
with

damper
oil

Assemble
the
nozzle
sleeve
washec
and
set
screw

by

temporarily
tightening
the
set
screw

Set
the
piston
to
its

fully

closed

position
and
insert
the
nozzle
until
it
contacts

the
nozzle

sleeve
When

the
nozzle

jet
contacts
the

jet
needle
the
nozzle

sleeve
must
be

slightly
adjusted
so

that
it
is
at

right
angles
to
the

centre
axis

and
positioned
to
leave
the
nozzle

jet
clear
of

the

jet
needle
Raise
the

piston
without

disturbing
the
setting
and

allow
it
to

drop
The

piston
should

drop
smoothly
until
the

stop
pin
strikes
the
venturi
with
a

liaht
metallic
click
See
below

under

Centering
the

jet
Tighten
the
nozzle
sleeve
set
screw

remove
the

nozzle
install
the
idle

adjustinJ
spring
and

adjusting

nut
on
the
nozzle
sleeve
and
refit
the
nozzle

39

1

Oil
cap
nut

2
Suction

chomber

3
Suction

piston

4

Li

tingpin

S

Stop
pin

6
Oil

dDmper

7

Plunger
3

j

I

r

L
2

1

Fig
0
17

Inspecting
the

suction

piston

STlq
O

OO

Fig
D
20

Checking
the
float
level
SU

twin
carburettors

q
J

iT

j

I

@

@

J
1
Conn

ctingrod

2

Wi
guard

3
Choke

lever

4

Connecting
plate

7
S
Thrott

adjusting
SC
Tt
W

6
Fast
id
lever

7

Throttle

adjusting
p1at

8
Throttle

valv

9

Throttlevalv
cletlran

B

Fig
D
22

Adjusting
the

starting
interlock

opening
inteN
lli
i

D

U
I

i

n

1
Jet
n
edle

2
Set
screw

Fig
D
18

Installing
the

jet
needle

1
Nozzle
sleeve

2
Wa
sher

3
Nozz
det
V
d
C1e
W

4

Ad
u
ting
him

5

dlingadjustment
spring

6

Idling
adjustment
nut

Z
Nozz
c
J

Fig
D
l9

Dismantling
the
nozzle

assembly

3

I
Float
lever

2
Bend
here

loadju5t

dimension
H

3
Va
veslem
r

F

Fig
D
21

Adjusting
the
float

level
SU

twin
carburettors

Fig
D
23

Checking
the

damper
oil

41