1969 DATSUN 610 heating

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

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

the
steel
balls
and
the
sleeve

yoke
for

damage
or
wear
Renew

the
boots
and
the
sleeve

yoke
plug
0

ring
if

necessary
Renew

the
universal

joint
jf

faulty

Check

the

play
in
the
drive
shaft

using
a
dial

gauge
as

shown
in

Fig
H
18
The
measurement
taken
with
the

dri
le

shaft

fully

compressed
should
not

exceed
O
lmm
0
004
in

Renew
the
drive
shaft
as

embly
if
the

specified
value
is
not

obtained

Oean

the
old
grease
from

the
sleeve

yoke
and
the
drive

shaft
ball

grooves
and
lubricate
with
oil

Asse

bly
of

the
drive
shaft

is
a

reversal
of
the

dismantling

procedure
noting
the

following
points

Align
the

yokes
and
make
sure
that

the
steel
balls

and

spacers
are
fitted

in
the
correct
order
Select
a

snap
ring
which

will

adjust
the
axial

play
of

the

universaIjoints
to
within
0
02mm

0
0008
in

Snap
rings
are
available
in

four
thicknesses
of

1
49
1
52
1
55

and
1
58
mm

0
0587
0
0598
0
0610

0
0622
in

Apply
a

generous

quantity
of
multi

purpose
grease
to
the

ball

groove
and
the
area
shown
in

Fig
H
19

REAR
AXLE
Removal
See

Fig
H
2

Estate
car
and
Van

Jack

up
the
vehicle
at
the
rear

and

support
it
on
stands

Remove

the
road

wheels
and
brake

drums
I

3
Disconnect
the
brake
hose
from
the

brake

pipe
Plug
the

end
of
the
hose
to

prevent
the

ingress
of

foreign
matter

4
Disconnect
the
handbrake
rear
cable
from

the
balance

lever

assembly

5
Disconnect

the

propeller
shaft
from
the
differential

flange

Release
the
lower
shock
absorber

self

locking
nuts
and

slide

the

mounting
eyes
of
the
shock
absorber
from
the

rear

spring
seat

pivot

6

Support
the
rear

axle
with

ajack
loosen
the
U
bolts
and

remove
the
nuts
from
the
rear

spring
shackles
Withdraw

the
shackles
from
the

spring
eyes

7
Remove
the
V
bolt
lock
nuts

completely
and
lower
the

jack
to

withdraw
the
rear
axle

assembly

REAR
AXLE

Dismailtling
and

Inspection

Disconnect
the
brake

pipes
from

the
wheel
cylinders
and

remove

the
brake

pipe
and
three

way
connector
Remove
the

cross
rod

clamp
and
the
balance
lever
from
the
rear
axle
case

Remove
both
cross
rod

ends
from
the

wheel

cylinder
lever

assembly

Unscrew
the
oil
drain

plug
and
drain
the
oil
from
the
axle

case
into
a
clean
container
The
oil

may
be
re
used
if
it
is
in

good
condition

Remove
the
nuts

securing
the
brake

backplate
to
the
axle

case
and
draw
out
the
axle
shaft

assembly
with
the

backpl
te

and
grease
catcher
A

sliding
hammer

ST
36230000
should
be

used
for
this

operation
as
shown
in

Fig
H
2Q

The

bearing
collar
can
be
removed
with
a

press
or

by

cutting
with
a
cold
chisel

and
the

bearing
withdrawn
with
the

puller
ST
3712001
as
shown
in

Fig
H
2t
Remove
the
brake

backplate
and
withdraw

the

gear
carrier
from

the
axle
case

Check
the
axle
shafts
for

straightness
wear
and
cracks

00
NOT

attempt
to

straighten
a
bent
shaft

by
heating
Check

the
oil
seal
lips
for

signs
of

damage
or
distortion
Make
sure

that

the

bearing
is
not
worn
or

damaged
REAR
AXLE

Assembly
and
Installation

Assembly
is
a
reversal
of
the

removal

procedure
noting
the

following
points

Thoroughly
clean
all

parts
and
fit
a
new

gasket
between

the
axle
case

and

gear
carrier

Tighten
the
nuts
in
a

diagonal

pattern
and
to

the

specified
torque
readings

Fit

the
grease
catcher

bearing
spacer
bearing
and
new

bearing
collar
onto
the
axle
shaft
A
load
of
4
5
tons
will

be

required
to

press
the

bearing
onto

the
shaft

Insert
the
wheel

bearing
with
the
seal
side

facing
the

wheel
and
ensure
that
the

oil
seal

lips
are
coated
with
wheel

bearing
grease
prior
to

fitting

Check
and

adjust
the
axial

play
between
the
wheel

bearing

and
the
axle

housing
using
a

dial
gauge
as

shown
in

Fig
H
22

The
axial

play
should
be

adjusted
to
within
0
3
0
5mm

0
0118
0
0197
in

on
the
1400
and
1600cc

models
and
to

within
O
lmm
0
0039
in
on

the
1800cc
models

Fill
the
rear
axle
with
the

specified
amount
of

oil
and

bleed
and

adjust
the
brake

system
as
described
in

the

appropriate

section

REAR
SPRING
Removal
and

Inspection

Estate
cars
aud
Vans

The
rear

springs
can
be
removed
in
the
following
manner

Jack

up
the

vehicle
at
the

rear
until
the
wheels
are
clear

of

the

ground
and

place
stands
under
the
rear
frame

Disconnect
the
shock
absorber
from

the

spring
seat

Fig
H
21a
and

support
the
rear
axle

housing
with

ajack

3
Take
off

the
locknuts

and
remove

the
U
bolts
shown

arrowed
in

Fig
H
2t
the

spring
seat
location

plates
and

seat

pads

4
Remove
the
nuts

securing
the
front
bracket
to
the

body

remove
the
bracket
from

the

spring
eye
and
car

body
and

withdraw
the
rear

spring

5
Remove

the

upper
and
lower

rear
shackle
nuts

Fig
H
23

and
remove
the
rear

spring
from
the
vehicle

Clean
the

spring
leaves

thoroughly
and
examine

them
for

fractures
or
cracks
Renew
the

assembly
if

necessary

Check
the
front

pin
shackle
U
boIts
and

spring
seat

for

signs
of
wear
cracks
and

damaged
threads
Renew
the

components
as

required

REAR
SPRING
Installation

Installation
of
the
rear

spring
is
a
reversal
of
the
removal

procedure
noting
the
following

points

The
front
bracket

pin
front
bracket

bushing
shackle

pin

and
shackle

bushing
should
be
coated
with
a

soapy
solution

prior
to

assembly

Tighten
the
front

pin
securing
nut

and
the
shock
absorber

lower

securing
nut
with
the
vehicle

weight
resting
on
the
rear

wheels

Ensure

that
the
flange
of

the
shackle

bushing
is

clamped

evenly
on
both
sides

The

tightening

torque
values
can

be
found

on
the

page

entitled
TIGHTENING

TORQUES

81

N
Engme
SYMPTOMS
I

Trouble
Shooting
Lubrication
System

SYMPTOMS

bed
t
f
I
h
i
1m
0
p
q
r
I
I
II
bed
t
f
I
h
Ii
I
m
n

ENGINE
WILL
NOT
CRANK

ENGINE
CRANKS
SLOWLY

ENGINE
CRANkS
BUT
OOES
NOT
START

ENGINE
STARTS
BUT
RUNS
FOR
SHORT

PERIODS
aNL
Y

ENGINE
I
tISFIRES
AT
LOW
SPEED

ENGINE
MISFIRES
AT
HIGH
SPEED

ENGINE
MISFIRES
AT
ALL
SPEEDS

ENGINE
MISFIRES
ON
ACCELERATION

AND
FAILS
TO
REV

ROUGH
IDLE

RUNS
ROUGH
AT
HIGH
SPEED

lACK
OF
POWER

POOR
CCElERA
nON

LACK
OF
TOP
SPEED

EXCESSIVE
FUEL
CONSUMmON

EXCESSIVE
OIL
CONSUMmON

PINKING

COMPRESSION
LEAK
PROIABLE
CAUSE

Faull
In
th
e
ltartinll
IYltem
Refer
to
the
ELECTRICAL

EQUIPMENT
leetion
fOI
dilllflOlIll

b
Eft
ineoiltoothick
Stiffenpne

d
Mechanieal
scimre

Flult
In
lhe
IpUlion
I
ltem
Refer
to
the
IGNITION

SYSTEM
IeCtion
for
di
I

f
Flult
the
fuellYlltm
Refer
to
the
FUEL
SYSTEM

Clion
or
di
l
OIII

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h
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EXCES9lVE
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nd
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m
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the
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heel
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ry

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e
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h
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m
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REMEDIES
SYMI
IOMS

b
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ce
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ot

Add
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the
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Ind

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lmeFnd

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SlfIpenJine
Ind
renew
p
ru
asn
celllry
I
bed
t
f
I
h
I
i
k
I
mn
0

OVERHEATING
ENGINE
FAILS
TO
REAOI

NORMAL
OPERATING
TEMPERAt
lRE

PROIAILE
CAUSE
REMEDIES

I
RetUne
enJine

h
Trace
ndseal

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seal

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11
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m
Excellive
arbon
depolit
in
thecylinden

In
ffici
enpneoil
uae
of
inferior
p1Ide
of
oil

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inrldi
lorlrea
I
Topupradil
v

b
Ti
htenbdtorftnc

I
t
rmify

e
Repl
cwaterpump

f
Rcpll
e
thermoltll

I
Replleclhermolt
t

h
RetimeiaTUlion

i
Unload
ear
check
brl
ktt

j
Trace
ndclu

k
TfI
cdUrblockaae

L
AdjUllcorrc
cth

m
Decarbonise
fO
tne
top
overh
uJ

Top
up
wlth
correct
rade
Dr
inifneceUlry

PUIl
lly
blink
off
in
winter
only

ENGINE

Dismantling

Remove

the

engine
from
the
vehicle
as

previously
described

and

carefully
clean
the
exterior

surfaces
The
alternator

distribu

tor

and
starter
motor
should
be
removed
before

washing
Plug

the
carhurettor

air
horn
to

prevent
the

ingress
of

foreign
matter

Place
the

engine
and
transmission
on

the
engine
carrier
ST4797

0000
if

available
and
dismantle
as
follows

Remove
the

gearbox
from
the

engine
Disconnect
the
intake

manifold

water
hose
the
vacuum

hose
and
the
intake
manifold

to
oil

separator
hose
Remove
the
intake
manifold
with
the

carburettor
Fit
the

engine
attachment
ST3720OG18
to
the

cylin

der
block
and

place
tre

engine
on
the
stand
ST371
00000

Remove
the
clutch

@
Ssembly
as
described
in
the
section

CLUTCH
Remove
the
exhaust
manifold
and
heat
baffle

plate

Take
off
the
fan
blades
and
remove
the
water

pump
pulley
and

fan
belt
Remove
the
rocker
cover
hose
manifold
heat
hose
and

by
pass
hoses

Remove
the

generator
bracket
and
the
oil
fIlter
Extract
the

engine
breather

assembly
from
above
Note
that
the
breather

is
fitted
to
the

guide
and
is
installed
with
a
O

ring
which
is

pressed
into
the

cylinder
block

Flatten
the
10ckwasher
and
unscrew
the
crankshaft
pulley

nut
Withdraw
the

pulley
with
the

puller
ST44820000
if
available

but
do
not
hook
it
in
the
V

groove
of
the

pulley

Remove
the
rocker
cover
and
take
off
the
rubber

plug

located
on
the
front
of
the
cylinder
head

Straighten
the
lock

ing
washer
and
remove
the
bolt

securing
the

distributor
drive

gear
and
camshaft

sprocket
to
the
camshaft
Remove
the
drive

gear
and
take
off
the

sprocket
See

Fig
A
3

Remove
the

cylinder
head
bolts
in
reverse

order
to
the

tightening

sequence
sOOwn
in

Fig
A
18
and
lift
off
the

cylinder

head
as
an

assembly
See

Fig
A
4
Note

that
in
addition
to
the

ten

cylinder
head
bolts
there
are
also
two
bolts

securing
the

chain
cover
to

the
head
Invert
the

engine
and
remove
the
oil

sump
Remove
the
chain
cover
and
oil

flinger
Take
off
the
nut

securing
the
oil

pump
sprocket
and
withdraw
the

sprocket
with

the
chain
in

position
as
shown
in

Fig
A5
Remove
the
oil

pump

and
stramer
Note

that
two
of
the

pump
mounting
bolts
are

pipe
guides

Remove
the

timing
chain
crankshaft

sprocket
chain
ten

sioner
and
chain

stop

Remove
the

connecting
rod

caps
and

push
the

piston
and

connecting
rod
assemblies

through
the
tops
of
the
bores

Keep

all

parts
in
order
so

they
can
be
assembled
in
their

original
posi

tions

Take

out
the

flywheel
retaining
bolts
and
withdraw
the

flywheel
Remove
the
main

bearing

caps
but
take
care
not
to

damage
the

pipe
guides
Lift
out

the
crankshaft
and
main
bear

ings
noting
that
the

bearings
must
be
reassembled
in
their

original

positions
Remove
the

piston
rings
with
a
suitable

expander
and

take
off
the

gudgeon
pin
clips
The

piston
should
be
heated
to

a

temperature
of
50
to
600
122
to
1400F
before

extracting

the

gudgeon
pin
Keep
the
dismantled

parts
in
order
so

they

can
be
reassembled
in
their

original
positions

Remove
the
camshaft
rocker
ann
shaft
and
rocker
ann

assemblies
from
the

head

by
taking
off
the
cam

bracket

clamp

ing
nuts
It
is
advisable
to
insert
disused
bolts
in
the
No
1

and

No
5
bracket
holes
as
the
cam
bracket
will
fall
from
the
rocker

ann
shaft
when

it
is
removed
Remove

the
valve

cotters

using

the

special
tool
ST47450000

and
dismantle
the
valve
assemblies
Keep
the

parts
together
so

they
can
be
installed
in
their

original

order

ENGINE

Inspection
and
Overhaul

Cylinder
head
and
valves

Inspection
and
overhaul

procedures
can

be
carried
out

by

following
the
instructions

previously
given
for
the
L14
LI6

and
LIB

engines
noting
the

following
points

Measure
the

joint
face
of
the

cylinder
head

using
a

straight

edge
and
feeler

gauge
The

permissible
amount
of
distortion
is

0
03
mm
0
0012
in
or
less
The
surface
of
the
head
must
be

reground
if
the
maximum
limit
of
0

1
mm

0
0039
in
is

exceeded

Oean
each
valve

by
washing
in
petrol
then

carefully
examine

the
stems
and
heads
Discard

any
valves
with
worn

or

damaged

stems
Use
a

micrometer
to
check
the
diameter
of
the
stems

which
should
be
8
0
mm
0
315
in
for
both
intake
and
exhaust

valves
If

the
seating
face
of
the
valve
is

excessively
burned

damaged
or
distorted
the
valve
must
be
discarded
The
valve

seating
face
and
valve

tip
can
be
refaced
if

necessary
but

only

the
minimum
amount
of
metal
should
be
removed
Check
the

free

length
and
tension
of
each
valve

spring
and

compare
the

figures
obtained
with
those

given
in
Technical
Data
at
the
end

of
this
section
Use
a

square
to
check
the

springs
for
deformation

and

replace
any
spring
with
a
deflection
of
1
6
mm
0
0630
in

or
more

Valve

guides

Measure
the
clearance
between
the
valve

guide
and
valve

stern
The
stem
to

guide
clearance
should

be
0
025
0
055
mm

0
0010
0
0022
in
for
the
intake
valves
and
0
04
0
077
mm

0
0016
0
0030
in
for
the
exhaust
valves
The
maximum
clear

ance

limit
is
0
1
mm
0
0039
in
The
valve

guides
are
held
in

position
with
an
interference
fit
of
0
040
0
069
mm
0
0016

0
0027
in
and
can
be
removed

using
a

press
and
valve

guide

replacer
set
ST49730000
under
2
ton

pressure
This

operation

can

be
carried
out
at
room

temperature
but
will
be
more
effec

tively

performed
at
a

higher
temperature
Valve

guides
are

available
with
oversize
diameters
of
0
2
mm
0
0079
in
The

cylinder
head
guide
bore
must
be
reamed
out
at

normal
room

temperature
and
the
new

guides
pressed
in
after

heating
the

cylinder
head
to
a

temperature
of

approximately
800
C
1760F

The
standard
valve

guide
requires
a
bore
of
14
0
14
018
mm

0
551
0
552

in
and
the
oversize
valve

guide
a
bore
of
14
2

14
218
mm
0
559
0
560
in
Ream
out
the
bore
of
the

guides

to
obtain
the
desired
finish
and
clearance
Use
the
reamer
set

ST49710000
to

ream
the
bore
to
8
000
8
015
mm
0
3150

0
3156
in
The
valve
seat

surface
must

be
concentric
with
the

guide
bore
and
must
be
corrected
if

necessary
using
the
new

valve

guide
as
axis

Valve
seat
inserts

Check
the
valve
seat

inserts
for

signs
of

pitting
The

inserts

cannot
be

replaced
but

may
be
corrected
if

necessary
using
a

valve
seat
cutter

ST49720000

Scrape
the
seat

with
the
450

cutter
then

reduce
the
width
of
the

contacting
faces

using
the

150
and
600
cutters
for
the
intake
valve
inserts
and
150
cutter

for
the
exhaust
valve
inserts
Seat
correction
dimensions
are

shown
in
millimeters
in

Fig
A
6

Lap
each
valve
into
its
seat
after

correcting
the
seat
inserts

Place
a
small

quantity
of
fme

grinding
paste
on

the

seating
face

of
the
valve

and
lap
in
as

previously
described
for
the
Ll4
LI6

and
L
18

engines

S5