MG MGB - Page 65

THE
ENGINE
5‘
PN’.‘
III/IIIIIIIIIIII
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’Illlll/Il/I/Ill
3NC962
Fig.
A. 32
Removing
a
gudgeon
pin, using
Service
tool
18G
1150
and
adaptor
set
18G
1150 D
‘A’
=
0.040 in.
(1
mm.)
end-■oat
Lock
screw.
Stop
nut.
Remover/replacer
bush ■ange
away
from
gudgeon
pin.
pin.
Gudgeon
pin.
Mark
the
bearing
caps
and
connecting rods for
reassembly,
marking
each
assembly
with
the
number
of
the
cylinder
from
which
it
is
taken.
Remove
the
big-end
nuts
and withdraw
the
bearing
caps.
Withdraw
the
piston and
connecting rod
assemblies
from
the
top
of
the
cylinder
block
and re■t
the
bearing
caps.
Dismantling
6.
7.
8.
10.
11.
12.
13.
Remove
the
piston
rings
over
the
crown
of
the
piston.
Hold
the hexagon
body
of
18G
1150
in
a
vice.
Screw
the large
nut
back
until
it
is
■ush
with
the
end
of
the
centre
screw,
ensure
the
screw
and large
nut
are
well lubricated,
and
push
the
screw
in
until
the
nut
contacts
the
thrust
race.
Fit
adaptor
18G
1150
D
on
to
the
centre
screw
with
the
piston
ring
cut-away
uppermost.
Slide
the
parallel
sleeve,
groove
end
first,
onto
the
centre
screw.
Fit
the
piston, ‘FRONT’
or
Atowards
the
adaptor,
onto
the
centre
screw.
Fit the
remover/replacer
bush
on
the
centre
screw
■ange
end
away
from
the
gudgeon
pln.
IMPORTANT.
The
gudgeon
pin
bore
is
offset
and
it is
essential
that
the
‘FRONT’
or
A
(marked
on
the
piston crown)
of
the
piston
is
■tted
against
the
adaptor
face.
Screw
the
stop
nut
onto
the
centre
screw
and adjust
to
the
correct
end-■oat (‘A’
Fig.
A.32).
Lock the
stop
nut
securely
with the
lock
screw.
Check
that
the
remover/replacer
bush
and
parallel
sleeve
are
correctly
positioned
in
the
bore
on
both
sides of
the
piston.
0
5. Front
of
piston.
6.
Piston
adaptor.
7. Groove
in sleeve
away
from
gudgeon
8.
Hexagon
body.
9.
Large
nut.
10.
Centre
screw.
14.
Screw
the
large
nut
up
to
the
thrust
race.
15.
Hold
the lock
screw,
and
turn
the
large
nut
(use
18G
587)
until
the
gudgeon
pin is
withdrawn
from
the
piston.
Reassembling
GUDGEON
PIN
16. Check
the
piston
and
connecting rod for
alignment.
17. Remove
the
large
nut
of
18G
1150
and
pull the
centre
screw
out
of
the
body
a
few
inches.
Ensure
the
nut
and
screw
are
well lubricated,
and the
piston
support
adaptor
is in
place.
18.
Slide
the
parallel
sleeve
groove
end last
onto
the
centre
screw
and
up
to
the
shoulder.
19.
Lubricate
the
gudgeon
pin and
bores
of
the
connecting
rod
and
piston
with
graphited
oil
(Acheson’s
Colloids
‘Oildag’).
Fit
the
connecting rod
and
piston
‘FRONT’
to
the
tool,
with the
connecting
rod
entered
on
the
sleeve
up
to
the
groove.
20. Fit
the
gudgeon
pin
into the
piston bore
up
to
the
connecting rod.
Fit
the
remover/replacer
bush ■ange
end
towards
the
gudgeon
pin.
21.
Screw
the
stop
nut
onto
the
centre
screw
and adjust
to
the
correct
end-■oat
(‘A’
Fig.
A.33).
Lock the
nut
securely
with the
lock
screw.
22.
Screw
the
large_nut
up
to
the
thrust
race.
23.
Set the
torque
wrench
18G
587
to
12
lb.
ft. (1.64
kg.
m.).
This
represents
the
minimum
load
for
an
acceptable
fit.
Using
the
torque
wrench
and 18G
587
on
the
large
nut,
and holding
the
lock
screw,
pull
the
gudgeon
pin
in until the ■ange
of
the
remover/replacer
bush
is
the
correct
distance
from
the
piston skirt (‘3’
Fig.
A.33).
MGB.
Issue
7.
87518