Datsun 1000 Workshop Manual page 20

14
Engine
TO CHECK CYLINDER BORES
9
LlNDER BOllES
AND PISTONS
DEGlAZING CYLINDER BORES
NOTE To accurately check cvUnder
bore condition alld
wear
it is essential that all
pistons
and
connecting
rod
assemblies be removed
from
the
cylinder
block also that
accurate measuring equipment be available
to
determine the
actual cvlinder bore overall
wear
including
taper
and
ovality The cylinder boTf
s
should be
wiped thoroughly
clean
with
a
clean rag
before checking
I
Visually
check the bores for cracks flaws
scuffing
or scoring
2 Check each
cylinder
bore for
wear
including taper
and
ovality
3
Cylinder
bores that
upon
checking
prove to be
unserviceable should
be
rebored and honed
to the
smallest
immediate
oversize
and
new
oversize
pistons
and
rings
filted
NOTE If
it is
found
that the
cylinders
leed
boring select
the
cylinder
with the most
wear
to detennine what oversize
pistons
aTe to
be used Bore all
cylinders to
that oversize
See Specifications for available
oversize
pistons
Engines that have been bored
to
their
extreme
limit
can
be filted
with
cylinder sleeves which
are
available
in
three
sizes
on
outer
diameter
New
pistons
and
rings
should still
be filted
with
sleeves
NOTE Cl
li lder
bores that
are
fit for further service with
original pistons but
require
re
nOnging should be
deglazed
with
a
hone
1
Position
plenty
of clean rag
over
the crankshaft
and under
each
cylinder
bore
to
keep
abrasive
materials
from
entering the crankcase
area
2
De glazing
of
the
cylinder walls
may
be done
by
using
a
cylinder
surfacing
hone
equipped with
280 grit
stones
3
Honing
should be carried
out
by moving
the hone
up and down the
cylinder
walls fast
enough to
achieve
a
cross
hatch pattern When hone marks
inter
ect
at
60
deg
the
Cross
hatch
angle
is most
satisfactory for the
correct
seating of piston rings
NOTE When
deglazing it is
important
t w t
only enough
strokes
of
the
hone
are
made
to
eliminate the
glazing
condition
of
the
cylinder
Excessive
honing
will
increase
bore
size and thus increase
piston
skirt clearance
4 Use
honing
oil which
is available from all major
distributors
Do not
use engine
or
transmission oil mineral
spirits
or
kerosene
5 After
honing it is
necessary
that
the cylinder block
be
thoroughly
cleaned
to
remove
all
traces
of abrasive
Piston and
Cylinder
Grade Numbers
Stamped
on
Pistons and Top of Cylinder Block
20