1977 DATSUN PICK-UP oil pressure

r

I

I

PRELIMINARY
CLEANING
AND

INSPECTION

DISASSEMBL
Y

PRELIMINARY

CLEANING
AND

INSt

ECTION

Before

disassembling

engine
note

the

following

I
Fuel

oil
or
water

may
leak

past

cylinder
head
and
block
Prior
to

disassembling
check

cylinder
head

1
1ltermal
vacuum
valve

2
Check

valve

3
Altitude

compensator

in

air
cleaner

4
Air

gallery
pipe

S

Auto
choke

6
Automatic

temperature

control
air

cleaner

7
Anti
8ackfire
valve
A
B

valve

8
Boost
Controlled

Deceleration

Device
Bee
D
D

9
P
c
v

valve

to
Air
relief
valve

11
E

G
R

control
valve

12
B
C
D
D

control
valve
and

solenoid
valve

13

Emergency
air

relief
valve

14
Air

pump
air
cleaner

IS
Carbon
canister

16
Air
control

valve

11
Air

pump
Engine
Mechanical

ENGINE

DISASSEMBLY

CONTENTS

EM
4

EM
4
PISTONS
AND
CONNECTING
RODS

CYLINDER

HE
AD
EM
7

EM
7

front
chain

cover
oil

pan
and
oil

filter

gaskets
lInd
crankshaft
and
water

pump
seals
for

signs
of

leakage
past

their

gasketed
surfaces

2
Check
carburetor
and

fuel

pump

for
condition
fuel
hoses
for

deteriora

tion
cracks

or

leakage
of
fuel

past

their

jointed
or
connected

surfaces

Fig
EM

0
Emiuion
control
devic
s

California
mod
18
E
T366

3
Remove

carburetor
air

cleaner

Remove
fresh

air
duct

Disconnect
hot
air
duct
from

air

cleaner

Disconnect
air

cleaner
to
air

pump

hose
at
air

cleaner

Disconnect
air

cleanef
to
rocker

cover

hose
at
rocker
cover

Disconnect

air
cIeaner

to
air

con

trol

valve
hose
at
air

cleaner
Cali

fornia

models

only
Disconnect
air

cleaner
to
A

B
valve

hose
at
air

cleaner

Disconnect
air

cleaner
to

related

part
vacuum
hoses
at
air

cleaner

Loosen
air

cleaner
band
bolt
and

remove
carburetor
air

cleaner
as

sembly
from

carburetor

4

Plug
up
carburetor
air

horn

to

prevent
entry
of

foreign
matter

5

Remove

alternator
drive

belt

alternator
and

alternator
bracket

EM
4
6

Remove
air

pump
drive

belt
cool

er

compressor
and
idler

pulley
if

so

equipped

7
Remove
starter
motor
from
trans

mission

8

Visually

inspect
cylinder
head

cylinder
block
rocker
C
Ner

front

chain
cover
oil

pan
and
all
other
outer

parts
for
oil
water
and
fuel
leaks

breakage
or

missing
parts
such

as
bolts

and
nuts

9

Check

piping
and
electrical
cir

cuits
for
deterioration

breakage
fit

tings
discontinuity
or
insulation

DISASSEMBLY

To

remove

engine
from
vehicle

refer
to

the
instructions
under
the

Engine
Removal

and
Installation

ER
section

I

Remove
transmission
from

en

gine

2
Remove

clutch

assembly
from

flywheeL

3

Thoroughly
drain

engine
oil
and

coolan
t

by

removing
drain

plugs

Store

engine
oil
and

coolant
if

they

are

to
be

used

again

4
Place

engine
assembly
on

engine

stand

I

Remove

cooling
fan

2

Remove

right
engine

mounting

bracket

3

Remove
oil
filter
with
Oil

Filter

Wrench
STI9320000

4

Remove
oil

pressure
swi

tch

5

Install

engine
attachment
to

cylinder
block

utilizing
bolt

holes
in

alternator

bracket
and

water
drain

hole

6
Set

engine
on
stand

Engine
Attachment

ST05260001

Engine
Stand

ST050I

SOOO

30
Install
heatshieid

plate
on
mani

fold
assembly

31
Install
air

gallery
pipe
on
ex

haust
manifold

32
Install
manifold

gasket
and

manifold

assembly
on

cylinder
head

Tightening
torque

1
2to
1

6kg
m

8
7
to
11
6
ft
lb

33

Install
blow

by
gas

pipe
on

cyl

inder

block
and
tighten
with
rear

engine
slinger

34
Install
thermostat
housing

gas

ket
thermostat

housing
and

thermo

stat

35
Install
thermal
vacuum
valve
on

thermostat

housing
Before

installing

apply
a

liquid
packing
slightly
to
the

threads

36

Install
FJ

C
D
bracket
on

cylin

der

head

37

Install
E
G
R

passage
and

E
G
R
valve
on
intake
manifold

38
Connect
E

G
R
tube
to
E

G
R

tube
and

exhaust
manifold

39
Install
check
valve

on
air

gallery

pipe

40
Install
air
cleaner
bracket
on

intake
manifold

41
Install
air
control
valve
on
air

cleaner
bracket
California
models

42
Install
vacuum
and
fuel
tubes

combined
on

cylinder
head

43
Install
distributor

assembly

44
Install

heatshield
plate

joint

seat

and
carburetor

Carbure10r
tightening

torque

0
5

to
1

0

kg
m
3

6
to
7
2

ft
lb

Note
When

instalUng
joint
seat
be

sure
to

put
the
duct
into

primary

hole
in

intake
manifold

S

J

Heatshield

plate
4
Joint

seat

2

Primary
hole
5

Secondary
hole

3
Duct

EM534

Fig
EM
I06

Installing
carburetor

joint
seat
Engine
Mechanical

45
Install
dash

pot
bracket
and

dash

pot
to
intake

manifold

46
Connect
all
air

vacuum
and
fuel

hoses

and
then

secure
with

clamps

I
Cylinder
block
to

P
C
V
valve

hose

2
A
B

valve
to
E

G
R

passage
vac

uum
hose

3
A
B

valve
to
E
G

R

passage
air

hose

4
Vacuum
tube
to
carburetor
vac

uum
hoses

5
Fuel
ube

to
carburetor
fuel

hose

6
Fuel
tube
to
fuel

pump
fuelhose

7
Distributor
to
vacuum
switch
or

spark
delay
valve
vacuum
hose

8
Air
control
valve
vacuum
hose

9
Check
valve

to
air

control
valve

hose

10
Thermal
vacuum
valve
to

E
G
R
valve
vacuum
hose

I
I
Thermal
vacuum
valve
to

vacuum
tube
hose

47
Install
carburetor
air

cleaner
on

carburetor
and
then
connect
air

and

vacuum
hoses

as
follows

I

Air
cleaner
to

exhaust
manifold

hot

air
duct

2

Air
c1eaner
to
air

pump
hose

3

Air
cleaner
to
rocker

cover
hose

4

Air
cleaner

to
air
control
valve

hose

5

6

48
Install

spark
plugs
in

place

49
Connect
all
distributor

high
ten

sion

cables
to

spark
plugs

50
Install
air

pump
drive
belt
cool

er

compressor
and
idler

pulley

51

Install
left

engine
mounting

bracket

52
Install
clutch

assembly
on

flywheel
with
Clutch

Aligning
Bar

KV30100200
Air

cleaner
to
A
B

valve

hose

Other
vacuum
hoses

Tightening
torque

1
2
to
2
2

kg
m

8

7
to
15
9

ft
lb

EM
26
I

I

KV30100200

EM440

Fig
EM
I07
In

talling
clutch
embly

53

Using
an
overhead
hoist
and

lifting
cable
hoist

engine
away
from

engine
stand
and

then
down
onto

engine
carrier

54
Install

right
engine
mounting

bracket
oil
filter
oil

pressure
switch

oil

level

gauge
and
water

drain

plug

When

installing
oil

filter
fasten
it
to

cylinder
block

by
hand

Note
Do
not

overtighten

flit
or
oil

leakage
may
occur

55
Install
alternator
bracket

adjust

ing
bar
alternator

cooling
fan

and

belt

56

Adjust
the
deflection
of
drive

belts
when

thumb

pressure
is

applied

midway
between

pulleys
A

pressed

force
is
above
10

kg
22
0
lb

Deflection

of
drive
belts

8
to
12
mm

0
315

to
0
472
in

EM613

Fig
EM
lOB
Fan
belt
tension

57
Fill

engine
oil

up
to

specified

level

Engine
Mechanical

SERVICE
DATA
AND
SPECIFICATIONS

GENERAL
SPECIFICATIONS

Engine
model
L20B

Cylinder
arrangement

Displacemen
t

Bore
and
stroke
4
in

line

cc
co
in

mm
in
1

952

J
19
1

85
x

86
3

35
x
3
39

O
H

C

I

3
4
2
Valve

arrangement

Firing
order

Engine
idle
rpm

Manual
transmission

Automatic
transmission
in
D

range
750

650

8
5

Compression
ratio

Oil

pressure
Warm
at
2

000

rpm

kg
cm2

psi
3
5
to
4
0
50

to
57

SPECIFICATIONS

a
Valve
mechanism

Valve

clearance
Warm

Intake

Exhaust

Valve
clearance
Cold

Intake

Exhaust

Valve
head
diameter

Intake

Exhaust

Valve
stem
diameter

Intake

Exhaust

Valve
length

Intake

Exhaust

Valve
lift

Intake
and
exhaust
mm
in

0
25
0
010

0
30
0
012

mmOn

0
20
0
008

0
25
0
010

mm
in

42
0
to
42
2
1
654

to
1

661

35

0
to
35
2
1

378
to
1
386

mm
in

7

965
to
7
980
0
3136
to

0
3142

7
945
to
7
960
0
3128
to

0
3134

mmOn

114
9
to
115
2
4
524
to
4
535

115
7
to
116
0
4
555
to
4

567

mmOn

Valve

spring
out

of

square
mm
in
10
5
0
413

less
than
1

6
0
063

Valve

spring
free

length
mm
in

Intake
and
exhaust
Outer

Inner
49
98
1
968

44

85
J
766

EM
27

Condition

Seized
valve

seat

Excessively
worn

cylinder
and

piston

Faulty
connecting

rod

Faulty
crankshaft

bearing
Engine
Mechanical

Probable

cause

Improper
valve

clearance

Weakened
valve

spring

Thin
valve
head

edge

Narrow
valve
seat

Overheating

Over

speeding

Stuck
valve

guide

Shortage
of

engine
oil

Dirty

engine
oil

Poor

quality
of
oiL

Overheating

Wrong
assembly
of

piston
with

connecting

rod

Improper
piston

ring
clearance

Broken

piston

ring

Dirty
aii

cleaner

Mixture
too
rich

Engine
over

run

Stuck
choke
valve

Overchoking

Shortage
of

engine
oil

Low
oil

pressure

Poor

quality
of

engine
oil

Rough
surface
of

craokshaft

Clogged
oil

passage

Bearing
worn
or

eccentric

Bearingimproperly
assembled

Loose

bearing

Connecting
rod

alignment
incorrect

Shortage
of

engine
oil

Low

oil

pressure

Poor

quality
of

engine
oil

Craokshaft

journal
worn
or

out
of
round

Clogged
oil

passage
in

crankshaft

Bearing
worn

or
eccentric

Bearing
improperly
assembled

Eccentric

craokshaft

or

bearing

EM
32
Corrective
action

Adjust

Replace

Replace
valve

Reface

Repair
or

replace

Drive
at

proper
speeds

Repair

Add
or

replace
oil

Clean

crankcase

replace
oil
and
oil
niter

element

Use

right
oil

Repair
or

replace

Repair
or

replace

Adjust

Replace

Clean

Adjust

Drive
at

proper
speeds

Clean

and

adjust

Start

correct

way

Add
oiL

Correct

Use

proper
oil

Grind
and

replace

bearing

Clean

Replace

Correct

Replace

Repair
or

replace

Add
or

replace

Correct

Use

proper
oil

Repair

Clean

Replace

Correct

Replace

ENGINE
LUBRICATION

SYSTEM

ENGINE

LUBRICATION
SYSTEM

CONTENTS

LUBRICATION
CIRCUIT

01
L
PUMP

Removal

Installation

Disassembly
and

assembly
EL
2

EL
2

EL
2

EL
2

EL
3
Inspection

OIL

PRESSURE

REGULATOR

VALVE

OIL
FILTER

RELIEF

VALVE
EL
3

EL
4

EL
4

EL
4

E
L049

Fig
Elr
I

Lubricating
circuit

LUBRICATION

CIRCUIT

The

pressure
lubrication

of
the

engine
is

accomplished
by
a
tro

choid

type
oil

pump
This

pump

draws
the

oil

through
the
oil
strainer

into

pump

housing
and
then
forces
it

through
the
full
flow

type
oil
filter

into
the

main
oil

gallery
Part
of
the

oil
is

supplied
to
all
crankshaft

bearings
chain

tensioner
and

timing

chain

Oil

supplied
to
crankshaft

bearings
is
fed
to

connecting
rod

bearings

through
the
drilled

passages

in
the
crankshaft
Oil

injected
from

jet
holes
on

connecting
rods
Iubri

cates
the

cylinder
walls
and

piston

pins
The

other

part
of
the
oil
is

brought
to

the
oil

gallery
in
the
cylinder
head
to

provide
lubrication

of
the
valve
mechanism

and

timing

chain
as
shown
in

Figure
EL
2

ELOSO

Fig
EL
2

Lubricating
vallie
mechanism

EL
2
From
this

gallery
oil
holes

go

directly
to
all
camshaft

bearings

through
cam

brackets

Oil

supplied

through
the
No
2
and

No
3
camshaft

bearings
is
then
fed

to
the
rocker

arm
valve
and
eam

lobe

through
the

oil

gallery
in

the

camshaft
and
the

small
channel
at
the

base
circle

portion
of
each
earn

OIL

PUMP

The

oil

pump
is

secured
on
the

bottom
of
the
front
cover
with
four

bolts
and
driven

by
the
oil

pump
drive

spindle
assembly
which
is

driven

by

the
helical

gear
on
the
crankshaft

The
oil

pump
assembly
consists
of

an
oil

pressure
regulator
valve
and

outer
and
inn
r

rotors

The

spring
loaded
oil

pressure
regu

lator
valve
limits
the
oil

pressure
to
a

maximum

of
5
6

kg
em
80

psi

Removal

I

Remove
distributor

2

Drain

engine
oil
if

necessary

3

Remove

oil

pump
body
with

drive

spindle

assembly

Installation

I

Before

installing
oil

pump
on

engine
turn
crankshaft

so
that
No
I

piston
is

at
TD
C

ENGINE
LUBRICATION
SYSTEM

2
Fill

pump
housing
with

engine

oil

then

align
punch
mark
of

spindle

with
hole
in
oil

pump
as
shown
in

Figure
EL

3

Punch
mark

EL009

Fig
EL
3

Aligning
punch
mark

and
oil
hole

3

Using
a
new

gasket
install
oil

pump
and
drive

spindle
assembly
so

that
the

projection
on
its

top
is

located
in
II
25
a
m

position
at

this
time
the
smaller
bow

shape
will

be

placed
toward
the
front
as
shown

in

Figure
EL
4

JI

I
c

J

V

Front
J

@
9@

tr
i

d

L
It
I

I
EL010

Fig
EL

4
Setting
drive

pindle

o

EL011

Fig
EL

5
Imtalling
oil

pump

Ascertain
whether

or
not

the
en

gagement
is
in
order

by
checking
the

top
of

spindle
through
distributor
fit

ting
hole

4

Tighten
bolts

securing
oil

pump

to
front
cover
Disassembly

and

assembly

I
Remove

pump
cover

attaching

bolts

pump
cover
and
cover

gasket

and
slide
out

pump
rotors

2
Remove

regulator

cap
regulator

valve
and

spring

3

Install

pressure
regulator
valve

and
related

parts

4
Install

outer
rotor
inner
rotor

and
shaft
in

pump
body
and
do
not

turn
cover

gasket
up

CD

El012

r

@
@

CD@

1

Oil

pump
body

2
Inner
rotor
and
shaft

3
Outer
rotor

4
Oil

pump
cover

5

Regulator
valve
6

Regulator
spring

7
Washer

8

Regulator
cap

9
Cover

gasket

Fig
EL

6
Oil

pump

Inspection

Wash
all

parts
in

cleaning
solvent

and

dry
with

compressed
ir

I

Inspect
pump
body
and
cover

for
cracks
or
excessive

wear

2

Inspect
pump
rotors
for
excessive

Rotor
side
clearance

rotor
to
bottom

cover
Olm
in

Rotor

tip
clearance

@
mOl
in

Outer
rotor
to

body

clearance

D
mm

inl

EL

3
wear

3

Check
inner

rotor
shaft
for

looseness
in

pump
body

4

Inspect
regulator
valve
for

wear

or

scoring

5

Check

regulator
spring
to
see

that

it
is
not

worn
on
its

side
or

collapsed

6

Using
a

feeler

gauge
check

tip

clearance
2
and

outer
rotor
to

body

clearance
I

shown
in

Figure
EL
7

1
Outer
rotor
to

body
clearance

2

Tip
clearance

3

Gap
between

rotor
and

straight
edge

4

Gap
between

body
and

straight
edg
e

Fig
EL
7

Checking
rotor
clearance

7

Place
a

straight
edge
across
the

face
of

pump
and

depress
it

slightly
as

shown
in

Figure
EL
7

Check

gap
4

between

body
and

straight
edge
or

gap

3
between

rotor
and

straight
edge

The

gap
should
be
0
03
to
0

06

mm

0
0012
to
0
0024
in
then

rotor
side

clearance
rotor
to
bottom

cover
clearance
with

gasket
should

satisfy
the

specifications

Standard
Wear

limit

0
04

to
0

08

0
0016
to

0
0032
0
20
0
0079

Less

than

0
12
0

0047
0

20
0
0079

0

15
to
0
21

0
0059

to
0
0083
0
5

0
0197

ENGINE
LUBRI
CATION
SYSTEM

Note

Pump
rotors
and

body
are
not

serviced

separately
If

pump
rotors

or
body
are

damaged
or
worn

replacement
of
the
entire
oil

pump

assembly
is

necessary

Tightening
torque

Oil

pump
mounting
bolts

Oil

pump
cover
bolts

Regulator
valve

cap
nut

Specifications

Oil

pressure
at

idling

Regulator
valve

spring

Free

length

Pressured

length

Regulator
valve

opening
pressure

OIL
FILTER

The
oil
filter
is
a

cartridge
type

The
oil
filter
element
should
be
reo

placed
periodically
with

the
use
of
Oil

Filter
Wrench
ST19320000

When

installing
an
oil
filter
fasten

it
to

cylinder
block

by
hand

Note
Do
not

overtighten
filter
or
oil

leakage
may
occur
OIL
PRESSURE

REGULATOR
VALVE

The
oil

pressure
regulator
valve
is

not

adjustable
At
the
released

position
the
valve

permits
the
oil

to

by
pass
through
the

passage
in

the

pump
cover
to
the
inlet
side
of
the

pump
Check

regulator
valve

spring
to

ensure
that

spring
tension
is

correct

kg
m
ft
Ib

kg
m
ft
lb

kg
m
ft
lb

kg
cm2

psi

mm
in

mm
in

kg
em
2

psi

RELIEF

VALVE

The
relief
valve
located
at
the

center

portion
securing
oil
fIlter
to

the

cylinder
block

by

passes
the
oil

into
the
main

gallery
when
the
oil

fIlter
element
is

excessively

clogged

STl9320000

EL015

Fig
EL
9

Removing
oil

filter

EL
4
EL014

Fig
EL
B

Regulator
value

l
l

to
1
5
8
0
to
11

0
7
to

1
0
5
Ito
7
2

4

to
5
29
to
36

0
8
to
2
8

II
to
40

52
5
2
067

34
8

1
370

35
to
5
0
50
to
71

With
oil
fIlter
removed
check

valve
unit
for

operation
Inspect
for
a

cracked
or
broken
valve
If

replace

ment
is

necessary
remove
valve

by

prying
it

out
with
a
screwdriver

Install
a
new
valve
in

place
by

tapping
it

EL016

Fig
EL
JO
Relief
lJOlue

ENGINE

LUBRICATION
SYSTEM

SERVICE
DATA
AND

SPECIFICATIONS

Oil

pump

Standard
Wear
limit

mm
in
0
04
to

0
08

0
0016
to
0
0032

less
than
0
12
0
0047

0
15
toO
21

0
0059
to
0

0083
0
20

0

0079

0
20

0
0079

0
5

0

0197
Rotor
side
clearance

rotor
to
bottom
cover

Rotor

tip
clearance
mm
in

Outer
rotor
to

body
clearance
mm
in

Oil

pressure
regulator
valve

Oil

pressure
at

idling

Regulator
valve

spring

Free

length

Pressured

length

Regulator
valve

opening

pressure
kg
cm2

psi
0

8
to
2
8

II
to
40

mm
in

mmOn

kg
em2

psi
52
5
2
067

34
8
1
370

3
5
to
5

0
50
to

71

Tightening
torque

Oil

pump
bolt

Oil

pump
cover
bolt

Regulator
valve

cap
nut
kg
m
ft
lb

kg
m
ft
lb

kg
m
ft

Ib
1
1
to
1
5
8
0

to
10
8

0

7
to
1

0
5
1

to
7
2

4
to
5
29

to
36

TROUBLE
DIAGNOSES
AND
CORRECTIONS

Condition
Probable
causes
Corrective
actions

Oil

leakage
Damaged
or
cracked

body
cover

Oil

leakage
from
gasket

Oil

leakage
from

regulator
valve

Oil

leakage
from
blind

plug
Replace

Replace

Tighten
or

replace

Replace

Decreased
oil

pressure
Leak
of
oil
in

engine
oil

pan

Dirty
oil
strainer

Damaged
or
worn

pump
rotors

Faulty
regulator

Use
of

poor
quality
engine
oiL
Correct

Clean
or

replace

Replace

Replace

Replace

Warning

light

remains
on

engine
running
Decreased
oil

pressure

Oil

pressure
switch
unserviceable

Electrical
fault
Previously
mentioned

Replace

Check
circuit

Noise
Excessive
backlash
in

pump
rotors

Replace

EL
5