1968 DATSUN 510 Service Repair Manual

44
CHAPTER
SIX

@

@

eight
connecting
rod
bolts
Remove
the
four

bottom

caps
along
with
assoc1ated
rod

beanngs

as
shown

m

Figure
25
Be
certain
to

identify

each

part
for

later

reassembly
on

the
correct

rod

3

Gently
push

up
each

connecting
rod
into

the

cylinders
far

enough
to

clear
the

crankshaft
Do

not

push
them

up
so
far
that
the

piston
rings
hit

the

ridge
at
the

top
of

the

cyImders
Remove
the

upper
beanngs
and

identify
for
later

reassembly

4
Remove

the
five
bolts

holding
the

flywheel

to
the

crankshaft
as
shown
in

Figure
26
For

models
Wlth
automatic
transmisslOn
there

is
a

convertor

plate
in
front
of
the
drive

plate
fly

wheel
and
a
crankshaft

plate
m

back
of
the

drive

plate
also

attached

by
the
five
bolts

5
Remove
bolts
from
front
main

bearing
cap

and
three
center
main

bearings
Identtfy
caps

and

beanngs
for

reassembly
@

NOTE
Removal

of
the
rear
mam

bearing

requires
the
use

of
a

specuzl

tool
ST4463000D
shown
in

f
Q

URE
27

6
Remove
the
rear
mam

bearing
cap
as
shown

in

Figure
28

7
Remove
the

rear
011

seal
as
shown
m

Figure

29

8
Remove

crankshaft
from

cylinder
block

9
Remove

and

1dentify
the
mam

beanngs
from

the

cyhnder
block

JOurnals

ENGINE
45

@

@

10
Remove
the
baffle

plate
and
steel
net
as

shown
in

Figure
30

11

Carefully
remove
the

connecting
rods
and

pIStons
from
the

cyhnders
by
pulling
them
out

of
the
bottom
of
the

cyhnder
block
@

12

Inspect
all

parts
for

signs
of

damage
or

wear

Repau
or

replace
as

reqUIred

PISTON
AND

CONNECI1NG

ROD
DISASSEMBLY

1
Remove
the

piston
nngs
from
the

pistons
as

shown
m

Figure
31

t
p

t

r
d

2
Removal
of
the

pISton
pms
from
the

pIStonS

and

connecting
rods

requires
the
use
of

a

press

and
tool
ST4484000D

CYLINDER
HEAD

DISASSEMBLY

I
Remove
the
valve
rocker

springs
that
are

looped
over
the

top
of
the
rocker
arms

2
Loosen
the
valve
rocker

pivot
lock
nut

and

remove
the

rocker
arm

by
pressing
down
the

valve

spnngs
on
each
valve
Take
care
not
to

lose
the
valve
rocker

gwdes
located
between
the

end
of
the
valve
stem
and
the
rocker
arm

46

CHAPTER

SIX

CAUTION

When

removing
camshaft
use
ex

treme
care
not

to
scratch

the
cam

bushings
Be
certam
to

leave
the
cam

shaft

bushings
Intact
so
as

not
to

get

them
out

of
al

gnment

3

Remove
camshaft
from
the

cylmder
head

by

carefully
pullmg
It

out
of

the
camshaft

beanng

housmgs
as
shown

m

Figure
32

@

4
Use
a
valve

hfter
as
shown
in

Figure
33

to

compress
the
valve

spnngs
so
that
the

valve

collects

located
at
the

tops
of
the
valve

stems

can

be
wIthdrawn
Once
the

collets
are

out
all

parts
of
the
valve

mechamsm
can
be
removed

from
the

cylmder
head

@

The
valves
are
removed

by

pullmg
them
out

the

bottom
SIde
of
the

cylinder
head

IdentIfy

each

upon
removal
to

permit
remstallation
in

the
same

posItion

Figure
34
Illustrates

the
var
@

o

o

IOUS

components
of
the
camshaft
and

valve

assembly

ENGINE

INSPECTION
AND

REPAIR

Once
the

engme
has

been

dIsassembled
clean

and

mspect
all

parts
to
determme
theIr
condi

tIon

CntIcal
dunenslOns
are
hsted
in
each

sec

tion
below

Cylinder
Head

CAUTION

Use
care
when

handling
the

cylinder

head

to
make
certam

that
the

cam

shaft

beanngs
are

not
removed

or

dIsplaced

1
Clean
all

foreign
matenal
from
the

cylmder

head

Pay

partIcular
attentIon
to

removal
of
car

bon
from

the
combustIon
chambers

Scrape
off

as
much
as

pOSSIble
and
remove
the
rest
with
a

wire

wheel
on
an
electric

dn11

2
Measure
the
machIned

surface
of
the
head

for

warpmg
FIgUre
35
covers
the

procedure
Use

a

StraIght
edge
and
feeler

gauge
Maxunum

@

ENGINE
47

allowable

warpage
IS
0
0039
in
0
I
mm

Standard
should
be
less
than
0
0012
in

O
03mm
In
the
event
the
measurements
are

out
of
tolerance
the

cylmder
head
surface

should
be
milled

or
resurfaced

3

Verify
that
all
water
and
011

passages
are
free

of

foreign
matena

Use

compressed
aIr
to
clean

passages
after

scraping

4
Note
the
condition
of
all
studs
in
the

cylinder

head

Replace
damaged
ones

Valve

Assembly

I
Check
intake
and
exhaust
valve
assembhes

for
worn

damaged
or
deformed
valve

caps
and

stems
Correct
or

replace
the
valve
If
excessive

defects
exist

2
Measure
valve
stem
diameter
WIth
a
micro

meter
as
shown
in

Fignre
36

Figure
37

gives

cnncal
drmensions

@

@

Y

lm

1

0
515

r

3
Reface
the
valve
face
and
valve
stem

using
a

valve

grinder
as
18
shown
in

Fignre
38
NOTE

When
the
valve
head

1uzs

been
reduced
to
00197
in
0
Smm

or
less
In
thIckness

replace
the
valve

Grinding
allowance

for
the
valve
stem

end

surface
is
00197
In
0
Smm
or

less

4
Measure
the
free

length
and
tension
of
each

valve

spring
If
the
measured
values
exceed
the

hnuts

specified
below

replace
the

spring

SPRING
SPECIFICATIONS

Free
Length
Outel

Spring

Inner

Spring

Outer

Spring
2
0472
10

52
Omm

1
765710
44
85mm

153m
at6393
331Ib

389mm
at290

15kg

138m
at
2712
154lb

35mm
at12
3
0
7

kg

121
10
at
105
38
5
29
Ib

30
7mm
at
47
8
2
4
kg

09610
at5621
2871b

245mm
at

25
5
13

kg
Valve
Closed

I
nner

Spring

Outer

Spnng

Valve

Open

Inner
Spnng

5
Check
the

deformation
of
each

spnng
with
a

square
Replace
any
spnng
WIth
a
deflection
of

o
063
in
I

611lID
or
more

6
Check
all

workmg
surfaces
of
the
rocker
arms

for

damage
or
wear
If
defects

or

apparent
ex

cessIve
wear

are
found

replace
them
A
defective

PIvot
reqwres
It
S

replacement
along
WIth
the

correspondIng
rocker
ann

7
Measure
the
clearance
between
the

valve

gwde
and
the
valve
stem
If
the
clearance
ex

ceeds
hnuts

replace
the
worn

parts
or
both

48
CHAPTER

SIX

valves
and
valve

guIdes
Figure
39
hsts

specifica

tions
for
the
valve

gwdes
PreCIse
measurement

reqwres
a
nncrometer
and
a

telescopIC
hole

gauge
Insert
the
hole

gauge
mto
the
valve

gwde

hole
and
take
measurements
at
three

places
top

u

mm
OIA

CO
527
o
as

n

C

S

EXHAUST

3mm
0

0
111110
0
I

J
aDo

INTAKE
10

f
tl

T1
I
f

I

J
c

c

E

E

@
108

mm
Co
425
od

o
mm

2
32
ln

center
and
bottom
Subtract

hIghest
readmg
of

valve
stem
dIameter
from
valve
bore
measure

ment
to
obtain
clearance
It

should
not
exceed

0
0039
m
0
Imm
As
an
alternatIve
measure

a
valve
can
be
mserted
in
the
valve

guide
and

moved
from
SIde

to
SIde
If
the

tip
of
the
vaJ
ve

stem
deflects

by
more
than
0
0079
m
0
2mm

replace
It

8

Replacement
of
valve

gwdes
should
be
re

ferred
to
an
automotive
mac
rne

shop

9
After

replacement

anI
reannng
of
the
new

valve

guIde
the
valve
seat
surface
m
the

cylmder

head
should
be
refaced

by
usrng
the
new
valve

gwde
for

tool

placement

10
Check
the
valve
seat
inserts
for
evidence
of

plttmg
at
valve
contact
surfaces
Reseat
or
re

place
the
valve
seat
mserts

depending
on
the

overall
condItion
Oversize
valve
seat
inserts

are
available

Figure
40
shows
the

specificatIons

for

standard
sIZe
valve
seat
mserts

Replacement

IS
a
machme

shop
Job
Tolerances
are
listed
in

FIgure
40

Camshaft
and

ClIIll8haft
Bearings

1
Measure
the
inner
dIameter
of
the

camshaft

bearing
and
the
ouier
dIameter
of
the
camshaft

journal

2
Detenmne
the
actual
clearances
and
com

pare
them
to
the

specifications
followmg
Ll6
With

Single
Carb

@

Intake

Exhaust

Od
Clearance
Standard

00015
10
0
0026
10

00381010
0
0761010

1
8898
10

1
8904
rn

48
001010
48
0161010
Wear
Lrmll

o
0039
rn

011010

Camshaft

Beanng

Inner
Olameter

3
ExceSSIve
wear
in
the

camshaft

beanngs
re

quires
replacement
of
the

cyhnderl
head
as

sembly

4
Check
the
camshaft

camshaft

JOurnals
and

cam
surfaces
for

signs
of
bend
wear
or

scoring

Figure
41
shows
the
camshaft

being
checked
for

bend
Bend
values
are

expressed
in
terms
of
half

values
of
the

readmgs
obtamed
when
the
cam

shaft

15
rotated
one
full
turn
WIth

a
dial

gauge

applied
to
the
center

Journal

@

Camshaft
Bend
standard

o
0006
10

00151010
Bend
Lrmll

00020
rn

0
051010

ENGINE
49

Cylinder
Block

1
Check
the

cylmder
block
for
defects
such

as

cracks

leaky
soft

plugs
and

blocked
water

pass

ages
Blowout
all

passages
With

compressed
air

2
Measure
the
surface
of
the

cylinder
block

that
mates
with
the

cyhnder
head
for

warpage

Use
a

straight
edge
and
feeler

gauge
to
measure

clearance
as
shown

m

Figure
42
Surface
flat

ness
clearance
should
be
less
than
0
0020
m

0
05mm
Maxunum
allowable
is
0
0039
in

010mm
Resurface
the

cyhnder
block
if

beyond
hnnts

@

3
Use
a

bore

gauge
as
shown
m

Figure
43
to

measure
the
bore
of

each

cyhnder
Measure
near

the

top
at
the
center
and

near
the
bottom
If

excessive
wear

taper
or
out
of
round
exists

rebore
the

cyhnders
or

replace
the

cylinder

hners
Maxunum
wear
hnnt
of
a

cyhnder
bore
IS

o
0079
m
0

2mm
Standard
bore
IS
3
2677

0
0020
m
83
000
0
050mm
The
al

@
lowable
error
m
the

cyhnder
bore

taper
is

0
0006
in
0015mm
The
difference
between

the
four

cyhnder
bores
should
not
exceed
0
0020

in
0
05mm

NOTE
When

any
cylmder
needs
re

boring
all

foUT
must
be
rebored

4
If
the

cyhnder
bores
are
Wlthm
tolerances

use
a

ndge
reamer
to
remove
the

ndge
at
the

top
of
the

cyhnder
bores
and
then
hone
the

cyhnder
walls
to

complete
the

recolllhuonmg

Measure
the

cyhnder
bores
when

honmg
has

been
finished
to

venfy
that
allowable
tolerances

have
not
been
exceeded

Measuring
Bore

Below
is
a
method
for

checking
cntical
clear

ance
between

piston
and

cylinder
wall
Unless

you
are
familiar
With
such

work
call
m
an

expert
Clearance
should
be
between
0
0010
and

0
0018
m
0025

thrQugh
0
045mm

1
Insert
the

pISton
without

rings

upside
down

in
the

cyhnder
bore

2
Use
a
feeler

gauge
between
0
0010
and

00018
mches
thick

Insert
It
between
the

pISton

and
the

cylinder
wall
as
shown

m

Figure
and

attach
a

spring
gauge
as
illustrated

@

50

CHAPTER
SIX

3
Pull

up
on
the

spnng
scale
If
the

force
re

qurred
to

pull
the
feeler

gauge
out
IS
more
than

3
3

lbs
or
less
than
0
44
Ibs

the

piston
skirt

IS
either

too

large
or
small
for
the

cyhnder
and

must
be

replaced
With

a

pISton
of
the

proper
size

EIther
that

or
the

cyhnder
must
be

rebored
or

a
new

cyhnder
hner

mstalled

Piston

Piston
Pin
and
Piston

Ring

1

Inspect
all

parts
carefully
for

signs
of

clups

cracks
and

general
wear

2
Measure
the
side
clearance
oLeac

ring
in

It
S

appropnate
groove
as
shown
in

Figure
45

Clearances
should
be
witlun
the

following
tol

erances

Top
Ring
00018

through
00031
In

0045

through
0
078mm

00012

through
0
0025
In

0030

through
0063mm

00010

through
0
0025
In

0025

through
0063mm
Middle

Ring

011

Ring
bottom

@

3
Check
the

gap
of
each

nng
by
mserting
it

about
1
mch
down
the
bore

squanng
it

With
the

wall

by
tappmg
It
WIth

an
mverted

pIston
and

measunng
the

gap
between
the
two
ends
of
the

ring
Figure
46
In
the
event
the

cyhnders
are

not

being
rebored
measure
the

nng
gap
toward

the
bottom
of
the
bore

where
the

least
wear

has
occured

4

Ring

gap
should

be
as
follows
Top
Ring
00091

through
0
0150
In

0
23

through
o
38mm

o
0059

through
0
0118
In

0
15

through
0
30mm

o
0059

through
0
0118
In

0
15

through
0
30mm
Middle

Rmg

0
1

Rmg
bottom

@

fJ
t

1

v

5
Measure
the

pIston
pm
hole
on
both
SIdes
of

the

pIston
Measurement
should
be
between

08268
and
0
8271
m
21
001
and
21
008mm

6
Measure

pISton
pin
outsIde
dIameter
With

a

nucrometer
as
shown

m

Figure
47
The
mea

surement
should
be
between

0
8265
and
0
8267

in
20
993
and

20
998mm

7
Measure

pIston
pm
length
It
should
be

between

2
835
and
2
844
m
72
00
and

72
25mm

ENGINE
51

8

Figure
48
shows
the

pm
bemg
mserted
to

make
certam
that

It
can
be

pressed
m
at
room

temperature
by
hand
Piston

pm
clearance
to

piston
pm
should
be
between
0
0003
and
0
0004

m
0008
and
0
01Omm

NOTE
The

piston
pin
IS

fitted
to
the

connecting
rod
with
a

fitting
force
of

from
1
to
3
tons

of

pressure

Connecting
Rod

1

Inspect
all

connectmg
rods
for
flaws
or

obVIOUS

damage

2
Check
for

proper
alignment
as
shown

m

Fig

ure
49

RealIgn
as

necessary
ThIS
can
be
done

by
an
automotive
maclune

shop
Maxrmum

allowable
bend

m
the

connecting
rods
IS
0
0020

m
0
05mm

per
3
94

m
of

connecting
rod

length

@
3
Defects
m
the

piston
pm
hole

reqwre
replace

ment

of
the

connectmg
rod
Select
new
ones
so

that

weight
dIfference
between
new
and
old
IS

wlthm
0212
oz
6

gr

4
Install

beanngs
m
the
crankshaft
end
of
all

rods
Mount
the
rods
on
the
crankshaft
and

replace
beanngs
and
rod

caps
Install
bolts
and

tighten
Use
a
feeler

gauge
to
measure
end

play

between
the

connecting
rods
and
the
crankshaft

Figure
50
The
standard
measurement
should

be
between
00079
and
0
0118
m
02
and

0
3mm
Maximum
allowable
wear
IS
00118
m

0
3mm

Crankshaft

1
Check
the
crankshaft

journal
and
crank

pm

1
1

for
cracks
obVIOUS
wear
and
scratcheS

Repair

or

replace
defective

parts
I

2
Check
the
crankshaft
for
bend
If
the
bend

at
the
center

Journal
exceeds
0
0020

m

0
05mm
have
the
crankshaft

prOfeSSIOnally

straightened
or

replace
It

3
Check
crankshaft

Journals
and
crank

pms
for

out
of
round
and

taper
Figure
51
lIsts

speci

fications

Regnnd
the
crankshaft
1f
the

specIfica

tions
are
exceeded

by
more
than
00012

m

0
03mm

4

Replace
the

connecting
rod
and
mam
bear

mgs
With

proper
undersIZe

beanngs
If
the
crank

shaft
IS

reground
The

followmg
table

prOVides

data
for

beanng
replacement
based

on
the

final

sIZe
of
the
crankshaft

Journals
and
crank

pIllS