Datsun 1300 - Page 18

12
Engine
ro m
SPRING
RETAINERS
A
A
OIL SEALS
I
J OUTER SPR
NG
9
INNER
SPRING SEATS
0
Q
I
l
J OIhiRlsPRING
SEATS
It
to
l
r
V
INLET VALVE
l
EXHAUST VALVE
l
Exploded
View
of Valve
and
Spring
Components
1
relevant
a rm
before attemptmg
to
compress
the
valve and
remove
the
iirm
f
f place
the rocker arms In a
rack
or
lay
them out
In
order to ensure
that
they
will be
Installed back
In theu
iigmal posIl
ons
4
6 Unsc
w
the
rocker arm
pivots
from
the
cyhnder
head and
remove
the
rocker
gUIdes
from the valve
stem
f
ends
Lay
tliese
components
also out In order to
ensure
r
cofrec
eplacement
7 Re
ove the two camshaft thrust
plates
to
caii1s i
1fro n
kbeanng
secunng
bolts and detach
the
thrust
plat
e
f
8
Carefully
withdraw
the
camshaft from the
cyhnder
head
ensurIng
that the camshaft
Journals
or
lobes
do not
dama
e
the camshaft
bearings
IMPORTANT Do
not
remove tHe
camshaft
bearmg
bracket
j
i
l s or
brackets
from
the
cylmder
head
assembly
If
i
bracket bolts
or
brackets are
removed
beanng misalignment 1 f
I
dl
result
which will
neceSSItate
the
renewal
of the
J
J
gylmder
head
assembly
v
9
USIng
a
sUItable
valve
spnng compressor compress
t
each valve
spnng
In
turn and remove
the
valve
retaInIng
coHets
IO
Remove
the
compressor
and hft off
the
spnng
retaIner valve
spnng
s valve stem 011 seal and
spnng
seat s DIscard
the
011 seals
4
l
J
I
I
I
Remove
any
burrs from
the
valve stem ends with
a
wardIng
file
to ensure that the valve
gUIdes
are
no
damaged
when the
valves
are
withdrawn
12 WIthdraw the
valves from the
cyhnder
head and
place
them In a
rack so
they
can be Installed In theu
ongInal pOSitIOns
when
reassem
bhng
the
cyhnder
head
i
TO
CHECK
AND
INSPECT
I
I
Clean the Valves
thoroughly
of carbon
depOSIt
and
discard
any
valve
that
IS
cracked
or
burnt
2
Reface
each valve
face
to the recommended
angle
as
shown
In the
specIficatIons
and each
valve stem flat and
true on a
sUitable valve
refacIng
machIne
Discard
any
valve
that
proves to
be
excessIvely
bent
tr
J
If a valve head has
een reduced to
0 50 mm 0
020 In
or less after
the
grindIng operatIon
then the valve
concerned should
be renewed
Valve
stem ends
may
only
be reduced
up
to 050 mm
I
3
Measure
the valve stem outer d13meter and
the t
valve
gUide
Inner
dIameter to
calcull
te the
actual
valvy
stem
f
to
gUIde
clearance
If clearance IS
In
excess
of
the
hrillt
of
o
I mm
0004 In then
he valve
guides
and or
valves
should be renewed
4
Remove
the
carbo l
Cdep oslts
from
the
cyhnder
head face
and the
valve
throats a ndcheck the
condltIons of
the valve seats
If
necessary
recut
the
seats wItlf
a
valve seat cutter to
the recommended
a
gre
and wIdth
I
F
1
1
NOTE
If
the
seats m the head
are worn
or
recesseq
excessively
then new
mserts
will have
to be
mstalled
It IS
recommended
that
the
mstallatlOn
of
new
valve mserts
and
or valve
guides If necessary
be
entrusted to
an
automotive
engmetrecondlllOner
who
has the
necessary
spepallsed
equIPfrfe
W
carry
out these
operdllons
5
Lap
the valves to
the
valve seats
with
a
lappIng
c01J1p
mnd
Apply
a smear
of
prusslon
blue to the
valves
Jafter IappIng and
check the
valves
on theu
respectIve
seats
to
ensure that
a
true and concentnc
seatmg
has
been
gaIned
6 With a
steel
straight edge
and feeler
gauge
check
the
cyhnder
head
face for
warpmg
If the
cyhnder
head IS
found
to be
warped
In
excess of the hmlt
speCified
see
SpecificatIons
then It Will be
necessary
to have
the head
surface
ground
to
bnng
the head
back
to
a
serYlceable
condItIOn
7
With
a
valve
spnng
tester check the
valve
spnng
tensIOns and
lengths
see
SpeCificatIons
If
a yalve
spnng
tester IS unavatlable
then
the test can be made
by
companng
the
used
spnngs
with
a new
spnng
Also check
the valve
spnngs
for
squareness
See
SpeCificatIons
for
squareness
hmIt Renew
spnngs
that
upon testIng prove
to
be unserYlceable
f
j
10
I
1
Il
A
L
1
18
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