engine DATSUN PICK-UP 1977 Repair Manual

6
Make

sure
that

crankshaft
has

proper
end

play

Crankshaft
end

play

0
05
to
0
18

mm

0

0020
to
0
0071
in

Fig
EM
89

Checking
crankshaft

end

play

7

Install
side
oil
seals
into

rear
main

bearing

cap
Prior
to

installing
apply

sealant
to
seals

Fig
EM
90

Driving
side
oil
seal

8
Install
rear
oil
seal

using
Crank

shaft
Rear

Oil
Seal
Drift

STI5310000

r

STl5310000

r

EM163

Fig
EM
91

Installing
rear
oi
seal
Engine
Mechanical

Note
When

installing
oil
seal

give

coating
of

engine
oil
to

mating

shaft
to

prevent
scratches
and

fold

ed

lip
Also

give

coating
of
oil
to

periphery
of
oil

seal

9

Install
rear
end

plate

10
Install

flywheel
securely
and

tighten
bolts
to

specified

torque

Tightening

torque

14

to
16

kg
m

101
to
116
ft
lb

I
I

Insert

pistons
in

corresponding

cylinder

using
Piston

Ring
Compressor

EM03470000

EM03410000

I

EM544

Fig
EM
92

Installing
pi8ton
rod

a
Sembly

Notes

a

Apply
engine
oil

to

sliding
parts

b

Arrange
80

that
notch
mark
on

piston
head
faces
to
front
of
en

gine

c
Install

piston
rings
at
1800
to

each

other

avoiding
their
fit
in
the

thrust
and

piston
pin
directions

6
Top
ring

I
iilring

Piston

pin
ireClioJ

EM165

Fig
EM

93
PUtan

ring
direction

12
Install

connecting
rod

caps

Tightening
torque

4
5
to
5
5

kg
m
33
to
40
ft
lb

EM
23
Fig
EM

94

Installing
connecting
rod

cap

Note
Install

connecting
rods

and
con

necting
rod

caps
80
that
their

as

signed
numbers
are

positioned
on

the

same
side
and
in
the
SlIme

direction
with

respect
to

cylinders

13
Make
sure
that

connecting
rod

big
end
has

proper
end

play

Fig
EM

95

Checking
big
end

play

Big
end

play

0
2
to
0
3
mm

0
008
to
0
Ql2
in

14

Install

cylinder
head

assembly

Fig
EM
96

Tightening
sequence

01

cylinder
head
bolts

J
Thoroughly
clean

cylinder
block

and

head
surface

Do

not

apply
sealant
to

any
other

part
of

cylinder
block
and
head

sur

face

2
Turn
crankshaft
until
No
I

pis

ton
is
at
T
D
C

on
its

compression

stroke

3
Make

sure
thai
camshaft
sprock

et
location
notch
and

plate
oblong

groove
are

aligned
at
their
correct

positions

4

When

installing
cylinder
head

make
sure

that
all
valves
are

apart

from
heads
of

pistons

5
Do

not
rotate
crankshaft
and

camshaft

separately
or
valves
will
hit

heads
of

pistons

6

Temporarily
tighten
two
bolts

CD

V
sJiown

in
Fig

re
EM
96

Tightening
torque

2

kg
m

14
ft
b

15
Install
crankshaft

sprocket
and

oil

pump
drive

gear
and
fit
oil

thrower

Note
Make
sure
lhat

maling
marks
of

crankshaft

sprocket
face
10
Cront

16
Install

timing
chain

Noles

a
Make

sure
that
crankshaft
and
cam

shaft

keys
point

upwards

Fuel

pump
drive

earn

2
Chain

guide

3

Chain
tensioner

4

Crank

sprocket

5
earn

sprocket

6
Chai

guide

EM439

b
Set

timing
chain

by

OOgning
its

mating
marks
with
those
oC
crank

shaft

sprocket
and
camshaft

sprock

et
at
the

right
hand
side
There
are

forty
four
chain
links
between
two

mating
marks
of

timing
chain

c
NO
2
hole
is

Cactory

adjusted

When
chain
stretches

excessively

adjust
camshaft

sprocket
at

No
3

hole

d
Use
a

set
of

timing
marks
and

location
hole

numbers
Engine
Mechanical

17
Install
chain
slack
side

guide
to

cylinder
block

18
Install
chain
tensioner

Note

Adjust
protrusion
oC
chain
ten

sioner

spindle
to
0
mm
0
in

Fig
EM
98

lmtalling
chain
tensioner

19
Press
new
oil
seal
in

front
cover

Notes

a
Front

cover
oil
seal
should
be
reo

placed
when
Cront
cover
is

disas

sembled

b
BeCore

pressing
oil
seal
into
Cront

cover

give
coating
of

engine
oil
to

periphery
of
oil
seal

c
This
oil
seal
is
a
threaded
seal

type

which
has

improved
sealing
charac

teristics
Do
not

apply
grease
to

sealing

lip

20
Install
front
cover
with

gasket
in

place

1

Timing
mark

2

Timing
mark

EM545

Fig
EM

99

Installing
fronl
COlHlr

Notes

a

Apply
sealant
to
Cront
cover
and

corners
oC

upper
section
of

cylinder

block

as
shown

in

Figure
EM
78

EM
24
b
Install
Cront
cover
with
head

gasket

in

place

c

Check

height
diCCerence
between

cylinder
block

upper
Cace
and
Cront

cover

upper
Cace
DifCerence
must

be
less
than
0
15

mm
0
0059
in

d

Note
that
difCerent

types
oC
bolts

are
used

e

Before

installing
front
cover
on

cylinder
block

apply

coating
oC

engine
oil
10

sealing
lip
of
oil

seal

EMS11

Fig
EM
lOD
Front

cover
bolts

Tightening
torque

Size
M8
0
315
in

1
0
to
1
3

kg
m
7

2
to
9
4

ft
lb

Size
M6
0
236
in

0
4
to
0
6

kg
m
2

9
to
4

3
ft
lb

21
Install
crankshaft

pulley
and

water

pump
assembly
then
set
No
I

piston
at
ToO
C
on
its

compression

stloke

Crankshaft

pulley
nu
I

tightening
torque

12
to
16

kg
m
B7
to
116
ft

lb

EM546

Fig
EM
Ol

lnstallingcran
haft

pulley
and

water

pump

22

Finally

tighten
head

bolts
to

the

specified
torque
in

three

steps

according
to
the

lightening
sequence

shown
in

Figure
EM
96

Note
thai
Iwo

types
of
bolts

are

used

Speci
ol

Cylinder
Head
Bolt

Wren
h

8110120000

Tightening
torque

1st
turn

4

0

kg
m
29

ft
lb

2nd
turn

6
0

kg
m
43
ft
lb

3rd
turn

6
5

to
8
5

kg
m

47
to
61
ft
lb

B
O

A

A

B

A

A
B
O

B
O

R
O

EM
176

Fig
EM
I02

Cylinder
head
boll

Notes

a
Be
sure
to

tighten
two
small
bolts

b
After

engine
has
been

operated
for

several
minutes

retighten
if
neces

sary

23
Install
oil

pump
and
distr
butor

driving

spindle
in

front
cover

Tightening
torque

1
1
to
1
5

kg
m

8
0

to
10
8
ft
lb

Notes

a
Assemble
oil

pump
and
drive

spin

die
aligning
driving

spindle
face

with
oil

pump
hole

b
Install
oil

pump
together
with

drive

spindle
so
that
the

projection
on
its

top
is
located
at
the
II
25
a
m

position
At
this

point
the
smaller

bow
shape
will
be

facing
toward
the

front

c
Do
not

forget
to
install

gas
et
Engine
Mechanical

I

Fig
EM

I04

11l6lalling
oil

pump

24
Install
fuel

pump
water
inlet

elbow
and
front

engine
slinger
in

their

positions

Fuel

pump
tightening
torque

1
2

to
1
8

kg
m

8
7

to
13

0
ft
lb

Note
Do
not

forget
to
install
fuel

pump
spacer
and

packing
between

spacer
and
block

spacer
and

fuel

pump

25
Install
oil
strainer
oil

pan
gasket

and
oil

pan

27

Install
rocker
cover
to

cylinder

head

Note
Make

sure
that
one
of
the

rocker
cover
bolts
is

longer
than
the

others
It
secures
F
I
C
D
assist

bracket

28
Install
air

pump
bracket
and

cooler

compressor
to

cylinder
block

EM
25
Tightening
torque

Oil
strainer

bolts

0

8
to
I
l

kg
m
5

8
to
8
0
ft

lb

Oil

pan
bolts

0
6
to
0
9

kg
m
4
3

to
6
5
ft

lb

Notes

a

Apply
sealant
to
the

step
portions

at

four

mating
surfaces

as
shown

in

Figure
EM
80

b

Oil

pan
should
be

tigh
tened
in

criss
cross

pattern
to
a
final

torque

of
0
6
to
0

9

kg
m
4
3
to
6
5
ft
lb

26

Adjust
valve
clearance
to
the

specified
dimensions

Special
tool

Pivot

Adj
iier
STl064000l

Tightening
torque

5

0
to
6
0

kg
m

36
to
43
ft
lb

Fig
EM
I05

Adjusting
valve
clearance

b
After

engine
has
been
assembled

run
it
for
at
least
several
minutes

and

finally
adjust
clearance
to
the

warm

specifications

29

Install
intake
manifold
to

ex

haust
manifold
The
intake
manifold

face
which
comes
into
contact
with

gasket
should
be
even
with
that
of

exhaust
manifold
Note
that
two
dif

ferent

sizes
of

attaching
bolts
are
used

Tightening
torque

2
5

kg
m

18
0
ft

lb

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

Valve

spring
pressured
length

valve

open

Intake
and
exhaust

Outer

Inner

Valve

spring
assembled
height

valve

close

Intake
and
exhaust

Outer

Inner

Valve

guide
length

Intake
and

exhaust

Valve

guide
height
from
head
surface

Valve

guide
inner
diameter

Intake
and
exhaust

Valve

guide
outer
diameter

service

parts

Intake
and
exhaust

Valve

guide
to
stem
clearance

Intake

Exhaust

Valve
seat
width

Intake

Exhaust

Valve
seat

angle

Intake
and
exhaust

Valve

seat
interference
fit

Intake

Exhaust

Valve

guide
interference
fit

b
Camshaft
and

timing
chain

Camshaft
end

play

Camshaft
lobe
ift

Intake
and
exhaust

Camshaft

joumal
diameter

1st

2nd
3rd
and
4th
Engine
Mechanical

mm

kg
in
lb

mm

kg
in
lb

mm
in

mIll
in

mm

in

mm

in

mm
in

mm
in

mm
in

mm
in

rnm
in

rnm
in

mm
in

Camshaft
bend

mm
in

Camshaft

journal
to

bearing
clearance
mm

in

Camshaft

bearing
inner
diameter
rnm
in

1st
2nd
3rd
and

4th
29
5
49
0
1
IM

108

24
5

25
5
0
965

56
2

40
0
21
3
1
575

47
0

35
0
12
3
1
378
27
I

59
0
2
323

10
6
0
417

8

000
to
8
018
0
3150
to
0
3157

12
223
to
12
234

0
4812

to
0
4817

0
020
to

0
053
0

0008
to
0
0021

0
040

to
0
073

0
0016
to
0
0029

1
4

to
1

6
0
0551
to
0
0630

1

8
to
2

2
0
0709
to
0
0866

450

0
081
to
0
113

0
0032
to
0
0044

0
064
to
0
096
0

0025
to
0
0038

0
027
to
0
049
0

0011
to
0

0019

0
08

to
038
0
0032
to
0
0150

7

0
0
276

47
949
to
47
962

1
8877
to
1

8883

0
02
0
0008

0
Q38
to
0
067
0
00
I
5

to
0
0026

48
000
to
48
016

1

8898
to
1
8904

EM

28

Engine
Mechanical

c

Connecting
rod

Center
distance

mm
in

Bearing
thickness
Standard

mm
in

Big
end

play
mm
in

Connecting
rod

bearing
clearance

mm
in

Connecting
rod
bend
or
torsion

per
100
mm
or
2
937
in

mm
in

d
Crankshaft

and
main

bearing

Journal
diameter

Journal

taper
out
of
round

Crankshaft

free
end

play

Wear
limit
of
dittoed

play

Crank

pin
diameter

Crank

pin

taper
out
of

round

Main

bearing
thickness
StJlndard
146
5

748

1
493
to
1

506
0
0588
to

0
0593

0
20
to
0
30

0
008
to

0
012

0
D25
to
0

055
0
0010
to
0
0022

less

than
0
03
0
0012

mm
in

mm
in

mm
in

mm
in

mm
in

mm
in

mm
in
59
942
to
59

955

2
3599
io
2
3604

less

than
0

0
I
0

0004

0
05
to
0
18

0
0020
to
0
0071

0
3

0
0118

49

961
to
49
974
1

9670
to
1
9675

less
than
0
01
0

0004

1

827
to
1

835
0
0719
to

0
0722

0

020
to
0
062
0

0008
to
0

0024

0
12

0
0047

0
05
0

0020
Main

bearing
clearance

mm

in

Wear
limit

of
dittoed
clearance
mm
in

Crankshaft
bend

mm
in

Flywheel
runout

at
clutch

disc
contact
face

mm
in

e
Piston

Pistondiarneter

Service
standard

0

50
0
0197
Oversize

1
00
0

0394
Oversize

Ring
groove
width

Top

Second

Oil

Piston
to
bore
clearance

Piston

pin
hole
off
set

Piston

pin
hole

diameter

f
Piston

pin

Pin
diameter

Pin

length
less
than
0
15
0

0059

mm
in
84
985
to

85
035

3

3459
to
3
3478

85

465
to
85
515

3
3648
to

3
3667

85
965
to
86
015

3
3844
to
3

3864

2
030
to
2

050
0
0799
to
0

0807

2

020
to
2

040
0
0795
to

0
0803

4
015
to
4
040
0
1581
to
0
1591

0
Q25
to
0
045
0
0010
to

0
0018

0
95
to
1

05
0

0374
to
0
0413

21
001
to
21

008
0
8268
to
0

8271
mm
in

mm
in

mm
in

mm
in

mm
in

mm
in

mm
in

20
993
to

20
998

0
8265
to
0

8267

72
25
to
73
00

2
8445
to
2
8740

0
008
to
om
0
0
0003

to
0
0004
mm
in

Piston

pin
to

piston
clearance

mm
in

Interference

fit
of

piston

pin
to

connecting
rod

bushing

mm
in

om
5
to

0
035
0
0006
to
0

00
I
4

EM
29

Engine
Mechanical

g
Piston

ring

Ring
height

Top
and

second

Side
clearance

Top

Second

Ring
gap

Top

Second

Oil
mm
in

mrn
in

mm
in

h
Cylinder
block

Cylinder
bore
inner
diameter
mm
in

Wear
limit
of
dittoed
inner

diameter

Cylinder
bore

taper
and
out
of
round

Difference
in

cylind
bore

Surface
flatness
mm
in

mm
in

mm
in

mm
in

i

Cylinder
head

Surface
flatness

mm
in

TIGHTENING
TORQUE

Cylinder
head

bolts

kg
m
fl
lb

Connecting
rod

big
end

nuts
kg
m
ft
Ib

Flywheel
fixing
bolts

kg
m
ft
Ib

Main

bearing
cap
bolts

kg
m
ft
lb

Camshaft
bracket
bolts

kg
m
ft
lb

Camshaft

sprocket
bolt

kg
m
ft
lb

Oil

pan
bolts

kg
m

ft
1b

Oil

pump
bolts

kg
m
ft
lb

Oil
strainer

bolts
kg
m

ft
lb

Oil

pan
drain

plug
kg
m
ft
lb

Rocker

pivot
lock
nuts

kg
m

ft
Ib

Camshaft

locating
plate
bolts

kg
m
ft
lb

Carburetor
nuts

kg
m

ft
lb

Manifold
bolts

kg
m
ft
lb

Fuel

pump
nuts

kg
m

ft
lb

Crank

pulley
bolt

kg
m
ft
lb

Water

pump
bolts

kg
m
ft
Ib

Front
cover
bolts

kg
m
ft

lb

EM

30
1
977
to
1
990
0

0778
to

0
0783

0
040
to
0
073
0
0016
to

0
0029

0

030
to
0

070
0
0012
to
0

0028

0
25
to

0
40
0
0098
to
0

0157

0

30
to
0

50
0
0118
to

0
0197

0
30
to
0

90
0

0118
to
0
0354

85
000
to
85
050

3
3465

to
3
3484

0
2

0
0079

om
5
0

0006

0
05
0
0020

less
than
0

05
0

0020

less
than
0
05

0
0020

6
5
to
8
5

47
to
61

4
5
to
5
5

33
to
40

14

to
16

101
to
116

4
5
to

5
5
33
to
40

1

8
to
2

0

13
to
15

12
to

16
87
to
116

0
6

to
0
9
4
3
to
6
5

I
J
to
1
5

8
0
to

10
8

0
8
to
1
1
5
8
to
8
0

2
0

to
3
0

14
to
22

5
0
to

6
0

36
to
43

0
6

to
0
9

4
3
to
6
5

0
5
to
1

0
3
6

to
7
2

1
2
to
1
6
8
7

to
11

6

1
2
to
1
8
8
7
to
13

0

12
to

16
87
to
116

0
4
to

0
5
2
9

to
3
6

8
mm
0
315
in

dia

6
mm
0

236
in
dia
1

0
to
1
3
7
2
to

9
4

0
4
to
0
6
2

9
to
4
3

Engine
Mechanical

TROUBLE
DIAGNOSES
AND

CORRECTIONS

Condition

I

Noisy
engine

Knocking
of
crankshaft

and
bearing

Knocking
of

piston

and

connecting
rod

Camshaft

knocking

Timing
chain
noise

Camshaft
and
valve

mechanism

knocking

Water

pump
knocking
Probable
cause

Loose
main

bearing

Seized
bearing

Bent
crankshaft

Uneven
wear

of

journal

Excessive
crankshaft
end

play

Loose
bearing

Seized

bearing

Loose

piston
pin

Loose

piston
in

cylinder

Broken

piston
ring

Improper
connecting
rod

alignment

Loose

bearing

Excessive
axial

play

Rough
gear
teeth

Broken
eam

gear

Improper
chain
tension

Worn
and
or

damaged
chain

Worn

sprocket

Worn
and
or

broken
tension

adjusting

mechanism

Excessive
camshaft
and

bearing
clearance

Improper
valve
clearance

Worn

adjusting
screw

Worn
rocker
face

Loose
valve
stem

i1
1
guide

Weakened
valve

spring

Seized
valve

Improper
shaft
end

play

Broken

impeller

II
Other
mechanical
troubles

Stuck
valve

Improper
valve
clearance

Insufficient
clearance
between
valve
stem

and

guide

Weakened
or

broken
valve

spring

Biting
or

damage
of
valve
stem

Poor

Quality
of
fuel

EM
31
Corrective
action

Replace

Replace

Repair
or

replace

Correct

Replace
cen
ter

bearing

Replace

Replace

Replace
pin
or

bushing

Recondition

cylinder

Replace

Realign

Replace

Replace
bearing
thrust

plate

Repair

Replace

Adjust

Replace

Replace

Replace

Replace

Adjust

Replace

Replace

Replace
guide

Replace

Repair
or

replace

Replace

Replace

Adjust

Clean
stem
or
ream
guide

Replace

Replace
or
clean

Use
ood
fuel

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