MG MGB User Manual

ENGINE
TUNING
DATA
18G,18GA,
AND 18GB
ENGINES
ENGINE
Type
.
Displacement
.
Firing
order
..
Compression
ratio:
H.C.
L.C.
Compression
pressure:
H.C.
L.C.
Idle
speed
Valve
rocker clearance
Static ignition
timing:
H.C.
L.C.
Stroboscopic
ignition
timing:
H.C.
L.C.
Timing
mark location
DISTRIBUTOR
Make/Type
Contact
breaker
gap
..
Contact
spring
tension
Rotation
of
rotor
Dwell
angle
Centrifugal advance
Crankshaft
degrees/speed
(vacuum
pipe
disconnected)
Vacuum
advance
Starts
Finishes
..
..
Total
crankshaft degrees
IGNITION
COIL
Make/Type
Resistance:
Primary
..
SPARKING
PLUGS
Make/
Type
Gap
CARBURETTERS
Make/Type
Jet
..
..
..
..
Needle:
18G
and
180A
engines
..
18GB
engine
Piston
spring
ELECTRICAL
Dynamo
..
Battery
..
.
Volts/Polarity
..
Starter
Control
unit
MGB. Issue
2.
25729
18G,
18GA,
18GB.
109.8
cu.
in.
(1798
c.c.).
1,
3, 4, 2.
8.8
:
1.
8.0
:
1.
.160
lb./sq.
in.
(11.25
kg./cm.2).
1301b./sq.
in.
(9.15
kg./cm.2).
500
r.p.m.
.015
in.
(.38 mm.)
set
cold.
10°
B.T.D.C.
8°
B.T.D.C.
14°
B.T.D.C.
at
600
r.p.m.
12°
B.T.D.C.
at
600
r.p.m.
Pointer
on
timing
case,
notch
on
crankshaft pulley.
Lucas/25D4.
.014
to
.016
in.
(.35
to
.40
mm.).
18
to
24
oz.
(510
to
680
gm).
Anti-clockwise.
60°i3°.
SERIAL
NUMBER
SERIAL
NUMBER
40897
(H.C.) 40916
(L.C.)
6°
at
600
r.p.m.
6°
at
600
r.p.m.
6°
at
700
r.p.m.
8°
at
800
r.p.m.
9°
at
900
r.p.m.
9°
at
1,000
r.p.m.
15°
at
1,600
r.p.m.
20°
at
2,200
r.p.m.
18°
at
3,000
r.p.m.
24°
at
4,400
r.p.m.
5
in.
Hg.
(127
mm.
Hg).
4
in.
Hg
(101.6
mm.
Hg).
13 in.
Hg
(330.2
mm.
Hg).
12 in.
Hg
(304.8
mm.
Hg).
20°i2°.
I6°i2°.
Lucas/HA12.
3.1
to
3.5
ohms
at
20°
C.
(68° F.).
Champion/N9Y.
.024
to
.026
in.
(.625
to
.66
mm.).
S.U./HS4.
.090
in.
(2.2
mm.).
N0. 5
(Std.),
No. 6
(Rich),
N0. 21
(Weak).
FX
(Std.),
N0. 6
(Rich),
No.
21
(Weak).
Red.
Lucas
C40/
1.
Lucas
BT9E
or
BTZ9E.
l2-volt/Positive earth.
Lucas
M418G Inertia-type.
Lucas
RB.340.
Engine
TuningData
1

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English