1973 DATSUN B110 low oil pressure

ENGINE

Spark
plugs

Cap
mm
in
0
8
to
0
9
0
03110
0
035

Idle
CO
ldie

speed

Manual
transmission

rpm

rpm
1
5

to
5
800

1
5
to
5

650
in
D

position
Automatic
transmission

Dash

pot

Setting

engine
speed

rpm
1
900

to
2
000

Throttle

opener
at
sea
level

Setting
vacuwn

pressure

Manual
transmission

Automatic
transmission

Setting

engine
speed
no
load

Servo

diaphragm
full
stroke
rpm

mm
in
500
to
540
19
7

to
21
3

480
to
520

18
9
to
20
5

1
650
to
1
850

5
0
1969
mmHg
in
Hg

mmHg
in
Hg

Theono
switch
Temperature
rises

from
low
to

high
oC
0

F
above
5

41

Flow

guide
valve

Opera
ting

pressure
mmHg
in

Hg
10
0
4

TROUBLE
DIAGNOSES
AND
CORRECTIONS

Troubles
Possible
causes
Remedies

CANNOT
CRANK

ENGINE
OR
SLOW

CRANKING
Improper
grade
oiL
Replace
with

proper
grade
oiL

Discharged
battery
Charge
battery

Defective

battery
Replace

Loosen
fan
belt
Adjust

Trouble
in

charge
system
Inspect
charge
system

Wiring
connection
trouble
in

starting
circuit
Correct

Defective
starter
switch
Repair
or

replace

Defective
starter
motor
Repair
or

replace

ET
26

I

Air
intake

system
in

trouble

Overheating

Overcooling

Others

NOISY

ENGINE

Car

knocking

Car
knock
when

coasting
ENGINE

Diny
ur

clogged
fuel
strainer

Fuel

pump
will
not
work

properly

Clogged
carburetor

jets

Clogged
air
cleaner

Air

inhaling
from
manifold

gasket
or
carbu

retor

gasket

Insufficient
coolant

Loosened
fan
belt

Worn
or
defective
fan
belt

Defective
thermostat

Defective
water

pump

Clogged
or

leaky
radiator

Defective
radiator
filler

cap

Air

mixing
into

cooling
system

Improper
grade

engine
oil

Incorrect

ignition
timing

Defective
carburetor

lean
mixture

Defective
thermostat

Low

octane
fuel

Improper
tire

pressure

Dragging
brake

Slipping
clutch

Overloading
to

engine

Carbon

knocking

Timing
knocking

Fuel

knocking

Preignition
misusing
of

spark
plug

Incorrect
throttle

opener
adjustment

Trouble
in
PCV
valve

ET
30
Replace

Repair
or

replace

Disassemble
and
clean

Replace
element

Replace
gasket

Replenish

Adjust

Replace

Replace

Replace

Flush

repair
or

replace

Replace

Retighten
each

part
of

cooling
system

Replace
with

proper
grade
oil

Adjust

Overhaul
carburetor

Replace

Replace
with

specified
octane
fuel

Adjust
to

the
specified

pressure

Adjust

Adjust

Use

right

gear
in

driving

Disassemble
cylinder
head
and
remove

carbon

Adjust
ignition
timing

Use

specified
octane
fuel

Use

specified
spark
plug

Adjust
throttle

opener

Replace
PCV
valve

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

r

Defective

connecting

rod

Defective
crankshaft

bearing
ENGINE

Shortage
of

engine
oil

Low
oil

pressure

Poor

engine
oil

quslity

Rough
surface
of
crankshaft

Clogged
oil

passage

Wear
or

eccentricity
of

bearing

Wrong
assembly
of

bearing

Loose

bearing

Incorrect

connecting
rod

alignment

Shortage
of

engine
oil

Low
oil

pressure

Poor

engine
oil

quality

Wear

or
out
of

round
of
crankshaft

journal

Clogged
oil

passage
in
crankshaft

Wear
or

eccentricity
of

bearing

Wrong
assembly
of

bearing

Not
concentric

crankshaft
or

bearing

EM
40
Add
or

replace
oil

Check
oil
level
on

daily
basis

Correct

Use

right
oil

Grind
and

replace
bearing

Clean

Replace

Repair

Replace

Repair
or

replace

Add
or

replace

Check
oil
level
on

daily
basis

Adjust

Use

right
oil

Repair

Clean

Replace

Repair

Replace

LUBRICATION
CIRCUIT

Oil
drawn

from
the
oil

pan
through
the
inlet

screen
and

tube

to
the
inlet
side
of
the
oil

pump
is
delivered

by
th

oil

pump
through
the
outlet

portion
of
the
oil

pump
and

the
oil

gallery
to
the
inlet

side
of
the
full
flow
oil

filter

and
to
the

main
oil

gallery

The
main
oil

gallery

supplies
oil
to
the

crankshaft
main

bearings
and

drilled

passages
in
the
crankshaft
and

thus

oil
is

fed

directly
from
the

main

bearings
to
the

connecting
rod

bearings

Oil

injected
from

jet
holes

on

connecting
rods

lubri

cates
the

cylinder
walls
and

pistion
pins

The
oil

distributed
from
the
main

gallery
enters
the

chain

teosioner
and
the

pad
is
held

against
the

chain

by

oil

pressure
and

spring
The
oil

also
lubricates
the

timing

chain

through
the

jet
hole

located

near
the
chain

Furthermore

lubricant
is

supplied
to
each
camshaft

bearing
through
each
crankshaft
main

bearing
and

finally

to
the
011

gallery
in
the
rocker

shaft

through
the
center

camshaft

bearing

The
rocker

arm
and
valve

are
lubricated

by
the
oil

through
the
oil

gallery
in
the

rockershaft

To
this

oil

gallery
lubricant

is

supplied
through
the

center

camshaft

bearing
as
shown

in

Figure
EL
I

OIL
PUMP

Description

The
oil

pump
assembly
is
installed
on
the
bottom
of

the

cylinder
block
and
driven

by
the
distributor

drive

shaft

assembly
The
oil

pump
is
of

a
rotor

type
The
oil

pressure
is

regulated
by
the

regulator
valve
camshaft

Removal

Engine
in
vehicle

Drain

engine
oil

2
Remove
the
frunt

stabilizer

3
Remove
the

splash
shield

board

4
Detach
the
oil

pump
body
together
with
drive

gear

spindle
ENGINE

Fig
EL
2
Removal

of
oil

pump

Disassembly

Prior
to

disassembling
check
to

determine
that
the

pump
is

defective

Take

out
a
total
of
2
bolts

securing
the

pump
cover

to
the

pump
body
The

outer
and
inner

rotors
and
drive

shaft
can

then
be

disassembled

2

Applying
a
suitable
wrench
or

spanner
loosen
off
the

regulator
valve

Note
a
When

placing
the
valve
in
a
vise
use
extreme

care
not
to
distort
the

pump
body
and
cover
in
the

jaws

b
Do

not

pull
out
the
drive
shaft

pin

securing
the

driven
shaft
and
inner
rotor
The
shaft
is

press

fitted
to
the
rotor
with
the

pin
calked

n

Trochoid

Fig
EL
Oil

pump

EL
2

ENGINE
LUBRICATION
SYSTEM

Inspection
and

repair

Clean
the
disassembled

parts
with

cleaning
solvent
and

inspect
for
defects

Inspect
the
drive
rotor
shaft
for

excessive
wear
and

scores
and
check

the
following
clearances

Side

clearance
between

Quter
and

inner
rotors
0
12
mm
0

0047
in
or
below

Tip
clearance
0
04
to
0
I2mm

0
0016

to
0
0047
in

Clearance
between
outer

rotor
and

body

0
15
to
0

21
rom
0
0059
to
0
0083
in

Adjusting
regulator

Insert
valve
in
the

body
and
measure
the
distance
A

from
the
valve
end
to
the

spring
contacting
face
inside
the

plug
See

Figure
EL
4

2
The
distance
from
the

spring
contacting
face
inside

the
valve
to
the
valve
end
amounts
to
18
mm

0
7086
in

3
On

inspecting
the
above

dimensions
determine
the

thickness
of

adjusting
shim

Shim
thickness
A
18

mm
0

7086
in

spring

length
at

compression
load
3
67

kg
8
091bs

Assembly

Assembling
the
oil

pump
is
the

reverse
order
of

disassembly

Note
3

Be
sure
no
traces
of

grinding
chips
lint
or
dirt

remain

b
Be

sure
gasket
is
not
turned

up
and
discon

tinued

OIL

PRESSURE

REGULATOR

VALVE

The
oil

pressure
regulator
valve
is
not

adjustable
At

the

released

position
the

valve

permits
oil

passing
through

a

passage
on
the

pump
cover
to
the
inlet

side
of
the

pump

Measure
the

regulator
valve

spring
dimension

to
ensure

that
the

spring
is

provided
with
the
correct
tension
e

Q

@

I

I
Adjusting
shim

2

Valve

spring

13
I
RegulatoT
valve

Fig
EL
4

RegulatoT
valve

Tightening
torque

Oil

pump
cover

bolts

kg
m
ft
lb
2
0
1
45

Oil

pump
mounting

bolts
kg
m

ft
lb
13
to

1
5

9
4to
II

Cap
nut

regulator

valve

kg
m
ft

lb
4
0
to
5
0

29
to
36

Specifications

Oil

pressure
at

idling

kgfcm2
Ibfsq
in
0
9
to
1
2

13
to
17

Regulator
valve

spirng

Free

length
mm
in

Pressured

length
mm
in
4349
l71

30
3
I
19

Regulator
valve

opening

pressure
kgfcm2
lbfsq
in
3
8
to
4
2

54
to
60

OIL

FILTER

The

oil
filter
is
of
a

cartridge
type
The
oil
filter
is

installed

or
removed

using
special
tool

The
filter
element
and
the
filter

body
are
caulked

together
I
t

must
be

replaced
with
a

new
one
as
an

assembly

When

installing
the

oil
filter
fasten
it
to
the
oil

pump

EL
3

Pinion
intermeshes

with

ring
gear

Starting
motor

rotates

and

pinion
intermeshes

with

ring
gear
but
ro

tation
is

too
slow

When

starting
switch
is

set
to
OFF
the
start

ing
motor
does
not

stop
Starting
motor

Battery

Wiring

Ignition
switch

Starting
motor

Ignition
switch

Magnetic
switch

Starting
motor
ENGINE

Faulty
pinion
sliding

Dropped
off
lever

pin

Excessive

plunger
L
dimension

Defective

over

running
clutch

Over

discharging

Improper
or
loose
terminal
contact

Improperly
tightened
connection

Rough
contact
surface

Shorted
armature
coil
or
field
coil

Worn
brush
or
insufficient

spring

pressure

Contaminated
commutator
or
im

proper
brush
contact

Defective
mica

Lack
of
metal
lubrication

Armature

contacted
with

pole
core

Faulty
returning

Seized
contact

Shorted
coil

Faulty

plunger
sliding

Pinion
does
not

disengage
from
the

ring
gear
smoothly

Pinion

spline
does
not

disengage

smoothly

Seized

pinion
metal

EE
14
Repair

Repair

Adjust

Replace

Charge
battery

Repair
and

retighten

Retighten

Repair
or

replace

Repair
or

replace

Repair
or

replace

Repair

Repair

Repair
or

replace

Repair
or

replace

Replace

Replace

Replace

Replace

Repair
or

replace

Repair
or

replace

Replace