1973 DATSUN B110 lock

ENGINE

3
Connect
a
3

way
connector
a

manometer
and
a

cock
or
an

equivalent
3

way
change
cock
to
the

end

of
the

vent
line

4

Supply
fresh
air
into
the

vapor
vent
line

through
the

cock
little

by
little

until
the

pressure
becomes
368

mm

Aq
14
5
in

Aq

5
Shut
the
cock

completely
and

leave
it
that

way

6
After
2
5
minutes
measure
the

height
of
the

liquid

in
the
manometer

7
Variation
of

height
should
remain
within
254

mmAq
1
0
in

Aq

8
When
the
filler

cap
does
not
close

completely
the

height
should

drop
to
zero
in
a

short
time

9

If
the

height
does
not

drop
to
zero
in
a

short
time

when
the

filler

cap
is
removed
it
is
the
cause
of
the

stuffy
hose

Note
In

case
the
vent
line
is

stuffy
the

breathing
in

fuel

tank
is
not

thoroughly
made
thus

causing

insufficient

delivery
of
fuel
to

engine
or

vapor

lock

It
must
therefore
be

repaired
or

replaced

3

way

connector

Cock

Air

Manometer
Vapor
liquid

seearator

Flow

guide
valve

E

CQ29

Fig
ET
40

Checking
evaporative
emission
control

system

Checking
flow

guide
valve

I
Disconnect
all
hoses
connected
to
the

flow

guide

valve

2
While
lower

pressure
air
is

pressed
into

the
flow

guide
valve
from
the
ends
of
vent
line
of

fuel
tank
side

the
air
should

go
through
the
valve
and
flow
to

crankcase

side
If
the
air
does
not
flow
the

valve
should

be

replaced
But
when
the
air
is
blown
from

crankcase

side
it
should
never
flow

to
the
other

two
vent
lines

3
While

the
air
is

pressed
into

the
flow

guide
valve
from
the
carburetor
air

cleaner
side

it
flows
to
the

fuel

tank
side
and
or

crankcase
side

4

This
valve

opens
when
the

inner

pressure
is
10

mmHg
0
4
in

Hg
In

case
of

improper

operations
or

breakage
replace
it

From

carburetor

air
cleaner

From
fuel
tank

i

I
I

ti

i

i

1
1

i
To
ran
kcase

E
C030

Fig
ET
41
Flow

guide
valve

Checking
fuel
tank

vaCCUID
relief

valve

operation

Remove
fuel
filler

cap
and
see
if
it
functions

properly

as

follows

Wipe
clean
valve

housing
and
have
it
in

your
mouth

2

Inhale
air
A

slight
resistance

accompanied
by
valve

indicates
that
valve
is
in

good
mechanical
condition
Note

also
that

by
further

inhaling
air
the
resistance
should
be

disappeared
with
valve
clicks

3

If
valve
seems
to
be

clogged
or
if
no
resistance
is
felt

replace
cap
as
an

assembled
unit

T

1i
v

rUr1f
AlI
j

r
I
r
tLMJJl

rr
L

cc

11

J
v

II

4J
L

Valve
I

valve
seat

Spring
Valve

housing

Fig
ET

42
Fuel

filler
cap

ET
24

ABNORMAL

COMBUSTION

backfire
afterflfe

run
on
etc

Improper
ignition
timing

Fuel

system
in
trouble

Defective

cylinder
head

etc

EXCESSIVE
OIL

CONSUMPTION

Oil

leakage

Excessive
oil

consumption
ENGINE

Improper
ignition
timing

Improper
heat

range
of

the

spark
plugs

Damaged
carburetor
or
manifold

gasket

backfire
afterflre

Defective
carburetor

jet

Improper
function
of
the
float

Uneven

idling

Improperly
adjusted
valve
clearance

Excess
carbon
in
the
combustion
chamber

Damaged
valve

spring
backfire
afterure

Loose
oil
drain

plug

Loose

or

damaged
oil

pan
gasket

Loose
or

damaged
chain
cover

gasket

Defective
oil
seals
in
front
and

rear
of
the

crankshaft

Loose
or

damaged
locker

cover
gasket

Improper
tightening
of
oil
filter

Loose
or

damaged
oil

pressure
switch

Worn

cylinder
and

piston

Improper
location
of
the

ring
split
or
reo

versed

assembly

ET
32
Adjust
the

ignition
timing

Use

specified
spark
plugs

Replace
them
with
new
ones

Disassemble
the
carburetor
and

check

it

Adjust
the
level
and

check
the
needle

valve

Adjust

Readjust

Remove
the

cylinder
head
and

remove

carbon

Replace
it
with

a
new
one

Tighten
it

Renew
the

gasket
or

tighten
it

Renew
the

gasket
or

tighten
it

Renew
the
oil

seals

Renew
the

gasket
or

tighten
it

Do
not

tighten
excessively

Renew
the

gasket
and

tighten
it
cor

rectly

Retighten
or
renew

the
oil

pressure

switch

Overhaul
the

cylinder
and
renew
the

piston

Reassemble
the

piston
rings
correctly

EMISSION
CONTROL
AND

TUNE
UP

Othm

POOR
FUEL

CONSUMPTION

See
the

explanation
of

the

power
decrease

Othe

TROUBLE
IN

OTHER

FUNCfIONS

Decreased
oil

pressure

Excessive
wear

on
the

sliding

parts
Damaged
or
seized

piston
rings

Worn

piston
ring
groove
and

rings

Fatigue
ofvalve
oil
seal

lip

Worn
valve
stem

Inadequate
quality
of

engine
oiL

Engine
overheat

Exceeding
idling
revolution

Defective
acceleration

recovery

Fuel

leakage

Inadequa
Ie
oil

quality

Overheat

Defective
function
of
oil

pump
regulator

valve

Functional
deterioration
of
oil

pump

Blocked
oil
ftIter

nerased
clearance
in
various

sliding
parts

Blocked
oil
strainer

Troubles
in
the
oil

gauge
pressure
switch

Oil

pressure
decrease

Defective

quality
or
contamination
of
oil

Defective
air

cleaner

Overheat
or
overcoal

ET
33
Renew
the

rings

Repair
or
renew
the

piston
and

cyl

inder

Renew
the

piston
and

piston
ring

Replace
the

seal

lip
with
a
new
one

Renew

the
valve
or
the

guide

Use
the

designated
oiL

Previously
mentioned

Adjust
it
to
the

designated
rpm

Adjust
it

Repair
or

tighten
the
connection

of

fuel

pipes

Use

the

designated
oil

Previously
mentioned

Disassemble
the

oil

pump
and

repair
or

renew
it

Repair
or

replace
it
with

a
new
one

Renew

it

Disassemble
and

replace
the
worn

parts
with

new
ones

Clean
it

Replace
it

with
a

new
one

Previously
mentioned

Replace
the
oil
with

proper
one
and

change
the

ftIter
elemerit

Replace
the
air

cleaner
element

Previously
mentioned

ENGINE
MECHANICAL

GENERAL
DESCRIPTION

CONTENTS

ENGINE

CYLINDER
BLOCK

CRAN
KSHAFT

PISTON
AND
CONNECTING
ROD

CYLINDER
HEAD
EM

EM
2

EM
2

EM
2

EM
2
CAMSHAFT

VALVE
MECHANISM

CAMSHAFT
DRIVE

MANIFOLD
EM

3

EM
3

EM
3

EM
3

ENGINE

The
AI2

engine
is
a
1
171
cc
71
5
cu

in
in
line
over

head
valve

four

cylinder
engine
with
73
mm

2
874
in

bore
and
70
mm
2
756
in
stroke
It
feature

full

opened
wedge
shaped
combustion

chamber
aluminum

heads
and

fully
balanced
5

bearing
crankshaft

to
turn
out

smooth

dependable
power

c

Ii

I
l

1

nun

y
r

r

Fig
EM
t

Sectional
view

of
At2

Engine

EM
1

ENGINE

CYLINDER
BLOCK

The

cylinder
block
in

a
mono
block

special
casting

structure

adopts
five

bearing

support
system

The
A
12

Engine
is

provided
with

baffle

plate
and
steel

net
to

reduce
oil

consumption
the
steel
net

scoops
oil

j
y

r

0

Q

0

T

Fig
EM
2

Cylinder
block

Fig
EM
3

Cylinder
block

CRANKSHAFT

The
crankshaft
is
made
of

special
forged
steel
and

provided
with

a
high

capacity
balance

weight
The

crankshaft

improves
engine
quietness
and

durability
t

high
speed
operation

The
main

bearing
are
lubricated
from
oil
holes
which

intersect
the
main
oil

gallery
in

parallel
with
the

cylinder

bores
v

Fig
EM
4

Crankshaft

PISTON
AND
CONNECTING
ROD

The

newly
designed
lightweight
piston
is

of
cast

aluminum

slipper
skirt

type

The
A
12

Engine
uses
concave
head

pistons
The

piston

pin
is
of
a

special
steel
hollow

type
and
is
connected
to

the

piston
in

a
full

floating
fit
and

to
the

connecting
rod

in

press
fit

The

connecting
rod
is

made
of

forged
steeL
Full

pressure
lubrication
is

directed
to
the

connecting
rods

through
drilled
oil

passages
from
the

adjacent
main

bearing

journal

Oil
holes

on
the

connecting
rod

journals
are
designed

so

that
oil
is

supplied
to

give
maximum
lubrication

just

before
full

bearing
load
is

applied

J

oO

o

e

Fig
EM
5
Piston
and

connecting
rod

CYLINDER
HEAD

The

cylinder
head
is

made
of

light
and

strong

aluminum

alloy
with

good
cooling
efficiency
A

special

aluminum
bronze
valve
seat
is
used
on
the
intake
valve

while

a

special
cast
valve
seat
is
installed
on
the
exhaust

valve
These

parts
are
hot

press
fitted

EM
2

ENGINE
MECHANICAL

Fig
EM
6

Cylinder
head

CAMSHAFT

Camshaft
is
made
of

special
cast
iron

and

supported
by

five
cannshaft

bearings

1

1

f

r

f

r

I

Fig
EM

Camshaft

Camshaft

bearings
are

lubricated
from
oil

holes
which

intersect
the
main

oil

gallery
of

the

cylinder
block

Concentric

passages
are
drilled
in

the
front
and
rear

parts
of
the

camshaft
for

supplying
oil
to
each

cam
lobe

through
an

oil
hole

drilled
in
the
base

circle
of
each
lobe

Lubricant
is

supplied
to
the
front

oil

gallery
from
2nd

camshaft

bearing
and
to
the

rear
oil

gallery
from
4th

camshaft

bearing

From
the
center
camshaft

bearing
lubricant
is

supplied

to
the
valve
rocker
shaft

through
the
center
locker
shaft

bracket

VALVE
MECHANISM

The
valve

system
has

push
rod

type
rocker
arm
which

uses
the

single
type
valve

springs
a

Fig
EM
8

Vol
mechanism

CAMSHAFT
DRIVE

The
camshaft
is

driven
with
a
double
row

roller
chain

which

is
driven

by
the
crankshaft

Tension

of
the

chain
is
controlled

by
the
chain

tensioner

which
is

operated
with

spring
and
oil

pressure

The
rubber

shoe

type
tensioner

insulates
vibration
of

the
chain
and
controls
tension

of
the

chain

Fig
EM
9

Comshdft
drive
chain

MANIFOLD

The
intake

manifold
is
a
mono

block
aluminum
cast

The

exhaust
manifold
is

made
of

a
cast
iron
The

semi

dual
exhaust

system
which
combines
exhaust

gas

flow
at
the

point
of
exhaust

pipe
connection

improves

exhausting
efficiency

The
exhaust
manifold
has

a
heat
control

valve
which

assures
stable

and
smooth

engine

running
after

starting

during
cold

season
The
manifold

is
connected
to
the

exhaust

pipe
by

flanges
which

completely
eliminate

exhaust

leaking

EM
3

ENGINE

Fig
EM
IO
Intake

manifold

Fig
EM
12
Intake

and
exhaust

manifolds

Fig
EM
It
Exhaust

manifold

ENGINE
DISASSEMBLY

CONTENTS

CLEANING
AND

INSPECTION

DISASSEMBL
Y
EM
4

EM
5
PISTON
AND
CONNECTING
ROD

CYLINDER
HEAD
EM
7

EM
7

CLEANING
AND
INSPECTION
breakage
rust

damage
and
loss

Clean
the

engine
thoroughly
before
disassembly

Before

cleaning
the

engine
remove
the
electrical

parts

and

plug
up
the
carburetor
air
horn
to
avoid
intrusio
n
of

foreign
matter
2

Cylinder
block

Check

thoroughly
the

water

jacket

for
cracks
and

breakage

3
Clutch

howing
Check
for
cracks

1
The

engine
exterior
Check
the

covers
and
bolts
for
4

Oil

pan
Check
for
excessive
rust

EM
4

ENGINE

J

I
r
I

I
J

fj

7
L

j
8

if

d1
I

ilfi
3

c

7

I
t

j

v

1

Ji

Fig
EM
27

Valve
mo
1

2
Be
careful
not
to
lose
valve

spring
seat
oil
seal
valve
collet
and
valve
rocker

spring

O

tj
AAAftIl

C

e
WWII

o

glAWle

Fig
EM
28

Valve

components

INSPECTION
AND
REPAIR

CONTENTS

PREPARATION
FOR
INSPECTION
EM
8

How
to
measure
cylinder
bore

EM
16

CYLlNOER
HEAD
AND

80ring
cylinder
EM
16

VALVES

EM
9

PISTON
PISTON
PIN
AND

Checking
cylinder
head

mating
face
EM
9

PISTON
RING

EM
18

Valve

assembly
EM
9

CONNECTING
ROD

EM
19

Valve

spring
EM
10
CRANKSHAFT
EM

20

Valve
rocker
shaft
and
rockei
arms

EM
lO
BUSHINGS
AND
BEARINGS

EM

21

Valve
lifter

and

push
rud

EM
11

Measuring
main

bearing
clearance

EM
21

Valve

guide
EM
11

Measuring
connecting
rod

bearing
clearance

EM
22

Valve
seat
inserts

EM
12

Fitting
crankshaft
bearings
EM
22

CAMSHAFT
AND

CAMSHAFT
BEARINGS
EM
14

Fitting
camshaft

bushings
EM
23

Measuring
camshaft

bearing
clearance

EM
14

MISCELLANEOUS
COMPONENTS
EM

24

Valve

timing
EM
14
Crankshaft

sprocket
and
camshaft

Checking
camshaft
for

bending
EM
14

sprocket
EM

24

CYLlNOER
BLOCK
EM
15

Flywheel
EM

25

PREPARATION
FOR
INSPECTION

L

Check
the

cylinder
head
and

cylinder
block
for

traces

of
water
leaks
before

cleaning

2

Clean
all

parts
to
remove
oil
stains
carbon

deposits
fur
and
other

foreign
matters

completely

3
Make

sure
that
all
oil
holes
are
clear
Blow
air
into

them
if

required

4

Secure

proper
assembly
carefully

EM
8