MG MGB User Manual

THE
IGNITION SYSTEM
Contact
breaker gap—Checking—Adjusting
13.
14.
15.
16.
17.
18.
19.
Turn the crankshaft until the heel
of the
contact
point
is
on
the highest
point
of
any
one
of
the
cam
lobes.
Check the
contact
gap;
it
should be 0.014
to
0.016
in.
(0.35
to
0.40 mm).
Adjust the
gap;
to
adjust
insert
a
screwdriver
in
the
slot
in
the
contact
breaker
plate
and
lever
against
the
pip
or
cutout
provided
on
the base
plate.
Tighten the
securing
screw.
Turn
the crankshaft
until
the heel of the
contact
is
on
the highest
point
of
and
alternative
cam
lobe.
Re-check the
contact
gap.
Repeat 17 and 18 for each
remaining
cam
lobe.
Distributor cap—checking
20.
21.
22.
23.
24.
Unclip
and
remove
the distributor
cap.
Remove
the
rotor
arm.
Using
a
clean, nap-free
cloth,
wipe
the
rotor
arm
and
the
inside
of the
distributor
cap.
Examine the
cap
and
arm
for
cracks
and
signs
of
electrical tracking.
Renew
if
necessary.
'
Check the
condition and
operation
of the
carbon
brush. Re■t the distributor
cap.
Distributor dwell angle
25.
26.
27.
Using
suitable
equipment,
check the
distributor dwell
angle.
Readjust the
contact
breaker
gap
to
obtain
the
correct
dwell angle
as
follows:
To
increase
the dwell angle,
reduce
the
contact
gap.
To reduce the
dwell
angle,
increase
the
contact
breaker
gap.
Re-check the
ignition timing, and adjust if
necessary.
Section
B.l6
DISTRIBUTOR—Lucas
type
45D4
A
q
1%.-
Removing
1. Disconnect the battery.
2. Remove the distributor
cap.
3. Rotate
the
crankshaft
until
the
groove
in
the
crankshaft pulley
lines
up
with
the
static ignition
point
on
the
timing indicator
(see
‘ENGINE
TUNING
DATA’)
and
at
the
same
time
the
distributor
rotor
arm
is
in
the ■ring
position
for
No. l sparking plug.
4.
Disconnect the low
tension
lead
from
the
wiring
harness.
5.
Disconnect
the
vacuum
pipe
from
the
distributor
vacuum
advance
unit.
6.
Remove
the
two
screws
securing
the
distributor clamp
plate
to
the cylinder
block.
7. Withdraw the distributor from
the
engine.
MGB.
Issue1.
89961
w■avewwr
3NC1042c
Fig. 13.1
The distributor
components
(Lucas
type
45D4)
Rotor
arm.
9.
Cam
spindleand automatic
Vacuum
unit. advance
weightsassembly.
Low
tension lead. 10.
Steelwasher.
Base
plate. 11. Spacer.
Base
plate (early cars).
12.
Capacrtor.
Retaining
pin—drivedog
13.
Contact
set.
Drive
dog.
14.
Low
tension lead
connector.
Thrust
washer.
B.9

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English