MG MGB User Manual

A
THE ENGINE
AD1386
Fig. A.21
Checking
the
piston ring
to
groove
clearance
raised
portion
of the
ring
until
it
rests
on
the land
above the
ring
grooves.
It
can
then be eased
off the
piston.
Do
not
remove or
replace
the
rings
over
the
piston
skirt,
but
always
over
the
top
of the
piston.
Before ■tting
new
rings
clean the
grooves
in
the
piston
to
remove any
carbon deposit. Care
must
be taken
not to
remove
any
metal
or
sideplay between the
ring
and
the
groove
will result,
with
consequent
excessive
oil
consumption
and loss
of gas-tightness.
When re■tting
the
rings
note
that the second and third
compression rings
are
tapered and
marked with the letter
‘T’
(top)
for
correct
reassembly.
Examination
Thoroughly clean
the bearing
shells and
the faces
of the
connecting
rods and
the
bearing
caps.
Examine
the
shells
for
wear,
pitting,
or
cracking,
and
renew
them if
necessary.
New shells
are
■nished with the
correct
diametrical
clearances
and do
not
require
bedding
in.
Blow the oil
passages
in
the
connecting
rods with
an
air
blast and
ensure
that they
are
free from obstruction.
Check
the
connecting
rods for
twist
and bow
as
shown
in
Fig.
A.22.
Do
not
■le the
caps
or
rods.
Check the
ring
to
groove
clearance
as
shown
in
Fig. A.2l.
AD1383
Fig. A.22
Checking
the
connecting
rod
alignment
New
rings
must
be
tested
in
the
cylinder bore
to
ensure
that
the ends do
not
butt
together.
The
best
way
to
do this
is
to
insert
the
piston
approximately
1 in.
(2.54 cm.)
into
the
cylinder bore, push
the
ring
down
onto
the
top
of the
piston,
and
hold
it
there
in
order
to
keep
it
square
with the
bore. The
correct
ring
gap
is
.008
to
.013 in.
(.20
to
.33
mm.).
Section
A.
1
5
PISTON
SIZES
AND CYLINDER BORES
In addition
to
the
standard
pistons
there
is
a range
of
oversize
pistons
available
for
service
purposes.
Oversize
pistons
are
marked with the actual
oversize
dimensions enclosed
in
an
ellipse.
A piston
stamped
.020
is
only suitable
for
a
bore
.020 in.
(.508 mm.)
larger than the
Fig.
A.23
Checking
a
piston
ring
gap
standard
bore; similarly,
pistons
with other markings
are
only suitable for the
oversize
bore
indicated.
The
piston
markings
indicate the actual bore
size
to
which
they
must
be ■tted, the
requisite running
clearance being
allowed for
in
the
machining.
After
reboring
an
engine,
or
whenever ■tting
pistons
differing
in size
from those
removed during dismantling,
ensure
that the
size
of
the
piston
■tted
is
stamped clearly
on
the
top
of
the cylinder block alongside the
appropriate
cylinder bore.
4
Section
A. l 6
CAMSHAFT
Disconnect
the
battery.
Remove
the
inlet
and exhaust manifold
assembly (see
Section A.4).
Remove
the push-rods
and
take
out
the
tappets
(see
Section
A.8).
MGB.
Issue
3.
1329

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English