1979 DATSUN 210 check engine

5

Fit
insert

ensuring
that
it

seats
on

bottom
face
of
its

recess

6

Newly
fitted
valve
seat
should
be

cut
or

ground
with
suitable
seat
cutter

or

grinding
stone

7

Apply
smalliunount
of
fine

grind

ing
compound
to
valve

contacting
face

and

put
valve
into

guide
Lap
valve

against
its
seat
ntil

proper
valve
seat

ing
is

obtained

Remove
valve
and
clean
valve
and

valve
seat

VALVE
ROCKER
ARM

1

AND
SHAFT

I

Check
rocker

arm
bore
and
shaft

for
scores
or
scuffs

2
Check
clearance

between
each

rocker
arm
and
shaft

by
measuring

inner
diameter
of

rocker
arm
bore
and

outer
diameter
of
shaft

If
either
clearance
is
not
within

spec
ification

replace
rocker
arm

and
or
shaft

3
Check
valve
end
contact
surface

of
rocker
arm
for
abnormal
wear
or

scuffs

VALVE
LIFTER
AND

PUSH

ROD

I
Check
valve
lifter
for

wear
or

scuffs
Check
bottom
end
of
valve

lifter
to
make
sure
it
has
a

slight

convex

Replace
valve
lifters
that
are

scored
worn
or
have
unsmooth
bot

tom

2
Check
clearance
between
lifter

hole
on

cylinder
block
and
valve
lifter

Replace
valve
lifter
if
clearance

ex

ceeds
wear
limit

3

Check

push
rod
for

bending
and

damage

Check
end
of

push
rod
for

rough

ness
or
excessive
wear

CAMSHAFT
AND

CAMSHAFT
BEARING

CAMSHAFT

BEARING

CLEARANCE

Journal
diameters
should
be
check

ed
with
a
micrometer
and

bearings

with
an
inside
dial

gauge
Measure

ments
should
then
be

compared
to
Engine
Mechanical

determine
whether

bearings
are
worn

If
worn

beyond
0
15

mm
0
0059
in

replace
using
Camshaft

Bearing
Drift

STl6Il0000
In

press
fitting
a
new

bearing
make
certain
that

oil
holes
in

block
and

bearing
are

properly
aligned

EM474

Fig
EM
27

Measuring
Camshaft

Bearing
Inner

Diameter

CAUTION

a

After

replacing
all

bearings
finish

bearing
inner
diameters

by
line
bor

ing

b
I
nstall
welch

plug
into

cylinder

block

applying
sealant

EM475

Fig
EM
28

Replacing
Cam
haft

Bearings

CAMSHAFT
ALIGNMENT

I

Check
camshaft
camshaft

journal

and
earn
surface
for

bending
wear
or

damage
If
fault
is

beyond
limits

replace
affected

parts

2
A

bend
value
is
one

half
of
the

reading
obtained
when
camshaft
is

turned

one
full
revolution
with
a
dial

gauge
applied
to
the
cen
ter

journal

Camshaft
bend

Total
indicator

reading

Less
than

0
10

mm
0

0039
in

EM
7
s

EM476

Fig
EM
29

Checking
Cam

haft
Bend

3

Camshaft
end

play
can
be
check

ed

by
installing
camshaft
camshaft

locating
plate
and
camshaft

sprocket

in

thier

respective
p
sitions

End

play

can
then
be

checked
with
a

dial

guage

or

feeler

gauge
If
end

play
exceeds
the

specified
limit

replace
locating
plate

Max

tolerance
of
camshaft

end

pley

0
10
mm
0

0039
in

EM477

Fig
EM
3D

Checking
Cam

haft
End

Play

VALVE
TIMING

This

diagram
applies
to
all

cyl

inders

If

any
valve
is
found

beyond

specifications
one

possibility
is

that

earn
lobe
is

worJ
1
or

damaged
exces

sively
calling
for

replacement
of
cam

shaft

CYLINDER
BLOCK

I

Visually
check

cylinder
block

for

cracks
or

flaws

2

Measure

top
of

cylinder
block

cylinder
head

mating
face
for

warp

age
If

warpage
exceeds
limits
correct

it

Warpage
of
cylinder
block

surface

Less
than

0
10
mm
0

0039
in

EM303

Fig
EM

31

Checking
Cylinder
Block

Surface

Note
Surface

grinding
6mit

Grinding
limit
of

cylinder
block
is

dependent
upon
cylinder
bead

grinding
of

engjne

Depth
of

cylinder
head

grinding
is

A

Depth
of

cylinder
block

b
1

b
is

U

The
limit
is

A
B
O
imm

0
008
in

The
total
of
A
and
B
should

not
exceed
0
2
mm
0
0079
in

3
With
bore

gauge
measure

cyl

inder
bore
for
out
of
round
or

taper
If

out
f
round

or

taPer
is
excessive
re

bore

cylinder
walls
with
a

boring

machine
Measurement
should
be

taken

along
bores
for

taper
and
around

bores
for

out
f
round

Out
of
round
X
Y

Taper
A
B

60
2

36

20
0
79

I
100
3
94

Ii

B

E9

I
Unit
mm
in

EM479

Fig
EM
32

Cylinder
Bore
Mea

uring

Positions

EM478

Fig
EM
33

Mecuuring
Cylinder
Bore

Diameter
Engine

Mecha
hical

4

When
wear

taper
or

out
of

round
is

minor
and
within
limits
re

move

ridge
at

topmost

portion
of

cylinder
using
a

ridge
reamer
or
similar

tool

CYLlND
ER
BORING

I

When

any
cylin
der
needs

boring

all
other

cY
linders
must
also

be
bored

at

same
time

2

Determine

piston
oversize

accord

ing
to
amount
of

cylinder
wear

3

The
size

to
which
c

linders
must

be
honed
is

determined

by
adding

piston
to
cylinder

clearance
to
the

largest
piston
diameter
at

piston
skirt

in

thrust
direction

f

EM126

Fig
EM
34

Measuring
Piston
Diameter

E

E

5

g

or

ge

I

PI

H

i

I
lEM480

Fig
EM

35
Piston
Diameter

Measuring

Position

Calculation
of

cylinder
bore
diame

ter
to

be
machined

D

A
B
C
A
0
003
to

0
023

mm
0
0001
to
0

0009
in

Where

D

Cylinder
bore

diaIpeter
to
be

machined

A

Piston
diameter
as
measured

B

Piston
to

cylinder
bore
clear

ance
0
023
to
0
043
mm

0
0009
to
0
0017
in

C
For

honing
allowance
0
02

mm
0
0008
in

EM
8
CAUTION

a
To

prevent
strain
due
to

cutting

heat
bore
the

cylinders
in
the
order

of
2
4
1
3

b
Before

boring

any
cylinder
install

main

bearing

caps
in

place
and

tighten
to
the

specification
so
that

the
crankshaft

bearing
bores
will

not
become
distorted

from
the
bor

ing
operation

4

Do
not
cut
too
much
out
of

cylinder
bore
at
a
time

Cut
0
05
mm

0
0020
in

or
so
in
diameter

at
a

time

5

Measurement
of

cylinder
bore

just
machined

requires
the
utmost
care

since
it
is

expanded
by

cutting
heal

6
As

a
final

step
cylinders
should

be
honed

to
final
size

7

Measure
finished

cylinder
bore

for
out
of

round

or

tapered

part

8

Measure

piston
to

cylinder
clear

ance

This
clearance
can

be
checked
easi

ly
with
a
feeler

gauge
and
a

spring

balance
hooked

on
feeler

gauge
meas

uring
amount
of
force

required
to

pull

out

gauge
from
between

piston
and

cylinder

Feeler

gauge
used

0
04
mm

0
0016

inl

Extracting
force

0
5
to
1

51rg

1
1

to
3
3
b

Note

a

Whenmeasuringcleanmce
slowly

pull
feeler

gauge
straight
upward

b
It
is
recommended
that

piston
and

cylinder
be
warmed
to
20

C

680F

r

EM379

Fig
EM
36

Measuring
Pi

ton
Fit
in

Cylinder

Note
If

cylinder
bore
has
worn

beyond
the
wear
limit
use

cylinder

liner

Undersize

cylinder
liners
are
avail

able
for
service

Interference
fit
of
cylinder
liner
in

cylinder
block
ahould
be
0
08
to

0
09
mm
0
003
I
to
0
0035
in

PISTON
PISTON
PIN

AND
PISTON
RING

I
Remove
carbon
from

piston
and

ring
grooves
with
a

carbon

scraper
and

a

curved
steel
wire

The
wire
will
be

useful
in

cleaning
bottom
land

of

ring

groove
Clean
out
oil
slots
in
bottom

land
of
oil

ring
groove

2

Check
for

damage
scratches
and

wear

Replace
if
fault
is
detected

3
Measure

side
clearance
of

rings
in

ring
grooves
as
each

ring
is
installed

If
side
clearance
exceeds
the

speci

fied
limit

replace

piston
together
with

piston
ring

Max
tolerance
of

side

clearance

0
1

mm
0
0039
in
Engine
Mechanical

u

EM482

Fig
EM
38

Measuring
Ring
Gap

Note

a
When

piston
ring
only
is
to
be

replaced
without

cylinder
bore
be

ing
corrected
measure
the

gap
at

the
bottom

of

cylinder
where
the

wear
is
minor

b

Oversize

piston
rings
are
available

for
service
0
5
mm
0
020
in
1

0

mm
0
039
in
oversize

5

Measure

piston
pin
hole
in
rela

tion
to
the

outer
diameter
of

pin
If

wear

exceeds
limit

replace
piston
pin

together
with

piston
on
which
it
is

installed

Piston

pin
to

piston
clearance

O
OOS
to
0
012
mm

0

0003
to
0
0005
in

Note

Determine
the

fitting
of

piston

pin
into

piston
pin
hole

to
such
an

extent
that
it
can
be

pressed

smoothly

by
fmger
at
room
tem

perature
This

piston
pin
must
be
a

tight
press
fit
into

connecting
rod

EM481

Fig
EM
37
Me

suring
Piston

Ring

Side
Clearance

4

Measure

ring
gap
with
a
feeler

gauge
placing
ring

squarely
in

cyl

inder

Ring
should
be

placed
to
diameter

at

upper
or
lower

limit
of

ring
travel

If

ring

gap
exceeds
the

specified

limit

replace
ring

Max
tolerance
of

ring

gap

1
0
mm
0
039
in
EM131

Fig
EM
39
Piston
Pin

Fitting

CONNECTING
ROD

1
If
a

connecting
rod
has

any
flaw

on
either
side
of

thrust
face
and

large

end
correct
or

replace
it

Bend
and
torsion

per
100
mm
3

94
in

length

Less
than

0
05
mm
0
0020
in

EM

9
EM133

Fig
EM

40
Checking
Rod

Alignment

2
Check

connecting
rod

for
bend
or

torsion

using
a

connecting
rod

aligner

If
bend

or
torsion

exceeds
limit
cor

rect

or

replace

3
When

replacing
connecting
rod

select
rod

so

weight
difference
be

tween
new
and
old
ones
is
within
5

gr

0
180z

4
Install

connecting
rods
with
bear

iogs
on
to

corresponding
crank

pins

and
measure

thrust
clearance
If
meas

ured

value
exceeds
limit

replace
con

necting
rod

Max
tolerance
of

big
end

play

0
4
mm
0
016
in

l
Big
end

play

l

t

t

EM483

Fig
EM
41
Checking
Big
End

Pwy

CRANKSHAFT

I

Repair
or

replace
as

required
If

faults
are
minor

correct
with

fine

crocus
cloth

2
Check
with
a
micrometer

journals

and
crank

pins
for

taper
and
out
of

round
Measurement
should
be
taken

along

journals
for

taper
and

around

journals
for
out
of

round

If
out
of
round

or

taper
exceeds

the

specified
limit

replace
or

repair

EM142

Fig
EM
48

Measuring
Bearing

Clearance

6
If
clearance
exceeds
the

specified

value

replase
bearing
with
an
under

size

bearing
and

grind
crankshaft

journal
adequately

Max
tolerance
of
main

bearing
clearance

0
10

mm
0
0039
in

MEASURING

CONNECTING

ROD
BEARING

CLEARANCE

I
Measure

connecting
rod

bearing

clearance
in
same
manner
as
above

tfl
Tightening
torque

Connecting
rod

cap
nuts

3
2
to
3
8

kg
m

23
to
27
fHb

2
If

clearance
exceeds
the

specified

value

replace
bearing

with
an
under

size

bearing
and

grind
the
crankshaft

journal
adequately

Max
tolerance
of

connecting

rod

bearing
clearance

0
10

mm
0
0039
in

Note
Since

bearings
are

precision

insert

type
it
is
not

necessary
to

file

bearing
caps
or
to

grindbeari

surfaces
with
an

emery
cloth
to

correct

bearing
clearance

MISCELLANEOUS

COMPONENTS

CRANKSHAFT
SPROCKET

AND

CAMSHAFT
SPROCKET

I

Check
tooth
surface
for
flaws
or

wear

Replace
sprocket
if
fault
is
Engine
Mechanical

found

2

Install
camshaft

sprocket
in

posi

tion

and
check
for
runout

If
runout
exceeds
the

specified

limit

replace
camshaft

sprocket

Runout

Total
indicator

reading

Less
than
0

1
mm
0
004

in

EM309

Fig
EM
49

Checking
Cam

haft

Sprocket
Runout

CHAIN
AND

CHAIN

TENSIONER

I

Check
chain
for

stepped
wear

scratches
or
other

problems
on

roller

links

Replace
if

necessary

2
Check
chain
tensioner
for
wear

breakage
or

any
other
fault
which

would

interfere
with

proper
chain

function

Replace
if

necessary

FLYWHEEL

I

Check

ring
gear
If
worn
or
dam

aged
excessively
replace

2

Clutch

contacting
face
of

fly

wheel

should
be
smooth
If

worn

damaged
or

roughened
beyond
limits

repair
or

replace

3
Before

disassembling
and
after

re

assembling
check

flywheel
run
out

with
a

dial

gauge
This
check
is

made

by
rotating
flywheel
with
dial

gauge

finger
resting
on
the
farthest

point

from
center
of

flywheel
If
it

exceeds

the

specified
limit

replace
it

EM
II
Runout

Total
indicator

reading

Less

then

0
15
mm
0
0059
in

Fig
EM
50
Checking
Flywheel
Runout

Note
Removal
and
installation
of

ring

gear
requires
use
of

hydraulic

press
It
is

also
necessary
to
heat

ring

gear
to
180
to
2000C
356

to

3920F
thus
facilitating
removal

and
installation
Do
not
heat

ring

gear
to
more
than
3000C
5nOF

To
do
so
could
result
in

impaired

hardness
of

ring

gear

CRANKSHAFT

FRONT
AND

REAR
OIL

SEAL

First
check
front
and
rear
oil

seals

for
worn
or
folded
over

sealing
lip
or

oil

leakage
If

necessary
replace
with
a

new
seal
When

installing
a
new
seal

pay
attention

to

mounting
direction

Note
It
is

good
practice
to

renew
oil

seal
whenever

engine
is
overhauled

Front

u
Front

Rear

EM487

Fig
EM

51
Cranhhaft
Oil
Seal

PRECAUTION

Before

assembling

engine
observe

following
precautions

I
Clean

all

disass
mbled

parts
with

clean
solvent
All
611
holes
in
crank

shaft

camshaft
valve

rocker
shaft
etc

should

be

thoroughly
cleaned
to
re

move
all

traces
of

grinding
chips
or

lint

Always
use
clean
solvent

2
In

general
used

gaskets
packings

and
oil

seals
should
be

replaced

3

Under
no
circumstances

should

lockwashers

be
reuse
d

4

Place
bolts

nuts
and
woshers

back
in

their

original
parts
or
from

which

they
were
removed

5
MOst

packing
Serve
best
when

liquid

packing
is

applied
to

sealing

surfaces
When

desigiiated
use
suitable

liquid
packing
to

eliminate

possibility

of
water
oil
and

gas
leak

6
Prior

to

assemQling
all

sliding

surfaces
should
be

lioerally
oiled

7

Proper

tightening
is
essential
to

successful

performanCe
of
all
car
re

pairs
It
is

also

important
to
follow

correct

tightenig
sequence
in

pulling

up
cylinder
head
Be

on
alert
at
all

times

to
amount
of

clearance

per

mitted

8
Cleanliness
of
tools
or

parts
such

as
work

bench
used
jn

making
a

repai

is
essential

When

setting
up
a

job

every
precaution
should
be
taken
that

tools
or

parts
are
free
of

dirt
mud
and

oil
Do

not
work

in
dust

and

grit
for

they
are

primary
cause
of
wear
in

any

engine

CYLINDER

HEAD

I

Install
valve

spring
seat
Install

valve
oil
seal

by
lightly

tapping
its

head
with

a

plastic
hammer

through

Valve

Lip
Seal
Drift
KVI0104800
Engine
Mechanical

ENGINE
ASSEMBLY

m

f

if
@

@

4

1
Valve

2

Lip
seal

3
Valve

guide

4
Valve

spring
seat
EM688

Fig
EM
52

tailing
Valve

Lip
Seal

2
Insert

valve
into

valve

guide

Note
Use
care
when

inserting
valve
so

as
not
to
scratch

lip
of
oil
seal

3
Install

valve

spring
and

valve

spring
retainer

Compress
valve

pring

with

Valve
Lifter
STl2070000
and
fit

valve
collets
in

place
Release
Valve

Lifter

slowly

EM462

Fig
EM

53

Inatalling
Valve

Note

8
Do

not

interchange
valves

between

cylinders
for
their

sliding
or

seating

surfaces
have

undergone

wearing
in

or
have

been

lapped
at

assembly

forming

specific
contact
with
mat

ing

parts

b
Check
to
be

sure
that
valves

are

properly
seated
on
valve
seats

with

out

foreign

particles
stuck

in
be

tween

c
Valve

spring
is
an

uneven

pitch

type
Install

spring
facing
Wte

painted
side
to

cylinder
head

sur

face

EM

12
p

lOted

l
rJF
t
A
J

il
j

j
Wide

pilCh
l

Nallow

pitch

I

EM489

Fig
EM
54
Valve

Spring

PISTON
AND

CONNECTING

ROD

I

Assemble

pistons
piston

pins
and

connecting
rods

on
the

designated

cylinder

EM103

Fig
EM

55

Installing
Piston
Pin

EM157

Fig
EM

56

Arranging
Piaton
and

Connecting
Rod

Note

3

Piston
is

pressed
into

connecting

rod

Fitting
force
is

from
1
to

3

tons

and
aid
of
Piston

Pin
Press

Stand
KVI

01
05300
is

necessary

When

pressing
piston

pin
in

connec

ting
rod

apply
engine
oil
to

pin
and

small
end

of

connecti
8
rod

b

Arrange
so
oil

jet
hole
of

connect

ing
rod

big
end
is

directed

toward

right
side
of

cylinder
block

c

Be
Sure
to
install

piston
in

cylinders

with
notch
mark

of

piston
head

toward
front
of

engine

9
Make
SUre
there
is

proper
end

play
at

crankshaft

Crankshaft

end

play

0
05toO
15mm

0
OO20
to
0

0059
in

laJlk
h
end

play

J

EM486

Fig
EM

63

Checking
Crank

luJft

End

Play

10

Install
rear

oil
seal

using
suitable

drift

Fig
EM

64
n

talling
Rear
Oil
Seal

II
Install
rear

plate

12
Install

flywh
el

secwely
and

tighten
bolts
to

specified
torque

dl
Tightening
torque

Flywheel
and
drive

plate

A
14

engine
fixing
bolts

8
0

to
9

0

kg
m

58
to

65
ft
Ib

Drive

plate
A
15

engine

fixing
bolts

8
5

to
9
5

kg
m

61
to
69
ft
b

Fig
EM
65
n

talling
Flywheel

13

Rotate

engine
quarter
turn

and

install

piston
rod

assembly
using
Pis
Engine
Mechanical

ton

Ring
Compressor
EM03470000

EM497

Fig
EM
66

tolling
Platon
Rod

Assem

bly

Note

a

Insert

pistons
in
L

r
nding
cyl

inders

b

Apply
engine
oil

to

sliding
parts

c

Arrange
pistons
so
number

stamped

on

piston
head
faces
to
front
of

engine

d
Before

installing
piston
piston
rings

should
be

positioned
as
shown
in

Fig
EM
67

Second

ring

Oil

ring
lower
rail

EM49B

Fig
EM
67

Positioning
Piston

Ring

Gap

14

Apply

engine
oil
to

bearing

surfaces

dl
Tighte
ning
torque

Connecting
rod

cap
nuts

3

2
to
3

8

kg
m

23
to
27
ft
b

EM499

Fig
EM

68

Tightening
Connecting

Rod

Cap

Note

Am11
connecting
rods
and

connecting
rod

caps
so

cylinder

numben
face
in
same
direction

EM
14
I

S
Make
sure
there

exists

proper

end

play
at

connecting
rod

big
end

See

Fig
EM41

Big
end

play

0
1
to
0
2

mm

0
004
to
0
008
in

16

Insert
crank

sprocket
keys
in

keyways
of
crankshaft

Install
cam

shaft
and

crankshaft

sprockets

tempo

rarily
for

adjustment
of
tooth

height

by
using
adjusting
washers

Height
dif

Less1
h
l11

0

5
mm
0

020
in

Adjusting
washer

thickness

0
5
mm

10
020

in

EM500

Fig
EM
69

Adju
ting
Sprocket

Tooth

Height

17
Install

tinting
chain
and
cam

shaft

sprocket
with
their

markings

properly
aligned
See

Fig
EM
70

Then
set
No
I

piston
at
T
D
C
on

compression
stroke
See

Fig
EM
71

Oil

sprocket
teeth
and
chain
with

engine
oil

Match
mark

Key
groove

EM501

Fig
EM
70

Aligning
Markinga

Note
Make
sure
camshaft

sprocket

dowel
hole
and
crankshaft

sprocket

key
are

in
line
and
both
dowel
hole

and

key
are
located
downward

m
k

camSM9tJ
down
hole

Key
groove

EM767

Fig
EM
11

Setting
No

I
Piston

atT
D
C

18

Tighten
camshaft

sprocket
bolt

ifl

Tightening
torque

Camshaft

sprocket
bolt

4
to
4
8

kg
m

29

to
35
fHbl

EM502

Fig
EM
72

Tightening
Camshaft

Sprocket
Bolt

19
Install
chain
tensioner
and

tight

en
tensioner

attaching
bolts

ifl

Tightening
torque

Tensioner

enaching
bolt

0
6
to
0
8

kg
m

14
3

to
5
8
ft
b

EM503

Fig
EM
73

Installing
Chain

Tensioner

20
Check

projection
L
of
ten

sioner

spindle

If

projection
L
exceeds
the

speci

fied
limit

replace
chain
Engine
Mechanical

Correct

projection
L

Less

than

15
mm
0
59
inl

lEM504

Fig
EM
74

Checking
Projection
of

Tf

nsioner

Spindle

21

Correctly
install
oil
thrower
in

front
of
camshaft

sprocket

22
Press
new
oil
seal
in

timing
chain

cover
F
ran
t

cover
oil
seal
should
be

replaced
when
front
cover
is

disassem

bled

23
Install

timing
chain
cover
with

gasket
in

place

Note
When

inatalling
oil
seal

apply

coating
of

engine
oil
to

mating

shaft
to

prevent
scratches
and
fold

ed

lip
Also

apply
coating
of
oil
to

periphery
of
oil
seal

ifl
Tightening
torque

Timing
chain

cover
bolts

0
5
to
0
7

kg
m

3
6
to
5
1
ft
Ib

Z5

1
o

j

I

t
f

4

EM455

Fig
EM
75

Installing
Timing
Chain

Covtr

24
Install
water

pump
with

gasket

in

place

ifl
Tightening
torque

Water

pump
attaching
bolts

0

9
to
1
4

kg
m

16
5
to
10
1
ft
bl

25
Install
crank

pulley
then
con

firm
and
set
No
I

piston
at
T

D
C
on

compression
stroke

EM
15
ifl
Tightening
torque

Crank

pulley
nut

15to
20

kg
m

108
to
145
ft
b

26
Invert

engine
Install
oil
stniiner

and
oil

pan
using
new
gasket
and

oil

seal

Note
Give

coating
of
sealant
to
seam

between
oil

pan
gasket
and
oil

pan

oil
seal

ifl
Tightening
torque

Oil

pan
bolts

0
4
to
0
6

kg
m

12
9
to
4
3
ft
lb

27
Install

gasket
and

cylinder
head

Note
Do
not

apply
sealant
to

any

other

part
of

cylinder
block

and

head
surface

28

Tighten
cylinder
head
bolts

ifl

Tightening
torque

Cylinder
head
bolts

7
0
to
7
5

kg
m

51
to
54
ft

IM

Note

a
One

of

cylinder
head
bolts
is
smal

ler

in
diameter
than
others
and
has

a
hollow
head
It
should
be
install

ed
on

right
side
center
of

cylinder

head

b

Tightening
should
be
made
in

two

or
three

steps
finally
torquing
to

specification

c

Retighten
cylinder
head
bolt
after

engine
has
been
warmed

up

Refer
to
Carburetor
Idle
R
P
M

and
Mixture
Ratio
EF
Section
for

Adjustment
and

Inspection

EM505

Fig
EM
76
Cylinder
Head
Bolt

Tightening
Sequence

Condition

Waterpurnp

knocking

II
Othw

mllChani

troubl

Stuck

valve

Seized
valve

seat

Excessively
wom

cylinder
and

piston
Engine
Mechanical

Probab
Ie
cause

Improper
shaft
end

play

Broken

impeller

Improper
valve
clearance

Insufficient
clearance
between
valve
stem
and

guide

Weakened
or
broken
valve

pring

Biting
or

damage
of
valve
stem

Poor
fuel

quality

Il1
prop
r
valve
clearance

Weakened
valve

pring

Thin
valve
head

edge

Narrow
valve

seat

Overheating

Over

speeding

Sticked
valve

guide

Shortage

ofengine
oil

Dirty
engine
oil

Poor
oil

quality

Overheat

Wrong
assembly
of

piston
with

connecting
rod

Improper
piston
ring
clearance

Dirty
air
cleaner

Too
rich
mixture

Engine
over
run

Stuck
choke
valve

Over

choking

EM
32
Corrective

action

Replace

Replace

Adjust

Clean
stem
or
ream
the

guide

Replace

Repil
ce
or
clean

Use

good
fuel

Adjust

Replace

Replace
valve

Reface

Repair
or

replace

Drive
at

proper
speed

Repair

Add
or

replace
oil

Check
oil
level
on

daily
basis

Clean
crankcase

replace
oil
and
re

place
oil
ftIter
element

Use

proper
oil

Repair
or

replace

Repair
or

replace

Adjust

Clean

periodically

Adju
t

Drive

correctly

Clean
and

adjust

Start
in
correct

way