Mg Mga twin cam Instruction manual

Series

MGA

Twin

Cam

WORKSHOP

MANUAL

NOTE

Refer to the end

of

the appropriate Section for the latest instructions when

carrying out work on the vehicle.

Additional copies

of

this publication (Part No. AKD926B) can only

be

obtained from an M.G. Distributor.

Issued by

THE

M.G.

CAR

COMPANY

LIMITED

Propri•tor.: Morris Motors Limited

ABINGDON

-ON

-THAMES

Exported by

NUFFIELD

EXPORTS

LIMITED

Propri•tors: Morris Motors Limited

COWLEY,

OXFORD,

ENGLAND

MGA (Twin Cam). Issue

3.

32403

INTRODUCTION

This Manual has been prepared to provide the service operator with the necessary

information for the maintenance and repair

of

the M.G. (Series

MGA

Twin Cam).

The Manual also serves as a ready-reference book for service supervision and covers

items

of

procedure for the guidance

of

both the fully qualified and the less-experienced

mechanic.

UNIT ARRANGEMENT

In the Manual the complete vehicle

is

divided into Sections each

of

which deals with

an assembly or major component and carries a reference letter.

NUMBERING

OF

~kGES

AND ILLUSTRATIONS

The pages and 1llustrations are numbered consecutively within each Section, and the

Section title and letter are shown at the top

of

each page.

SERVICE TOOLS

Use

of

the correct tools contributes to

an

efficient, economic, and profitable repair.

References have therefore been made

to

such tools throughout the Manual.

MGA (Twin Cam).

Issue

3.

32403

CONTENTS

Section

General

Data

Engjne A

Ignition Equipment B

Cooling System c

Fuel System D

Clutch E

Gearbox F

Propeller Shaft G

Rear Axle H

Rear

Road

Springs I

Steering Gear J

Front Suspension K

Hydraulic Dampers L

Braking System M

Electrical Equipment N

Wheels, Tyres, and Jacking 0

Lubrication p

Chassis R

Body

..

s

MGA

(Twin Cam). Issue

3.

32403

3

r--

J

i I

I !

i l

i

I l

! I

I

I I

l

i

~

I

.

~

I

~

i

< i

!

~

i

i 00

i I

I 0

l

~

f

i

~

!

-

e !

~

i

u I

.51

i

~

!

~

i

< i

C-'

::;;

riJ

~

·-

...

~

00

-

.

C-'

:i

~

:I:

~

4 MGA

(Twin

Cam)

. Issue

3.

32403

I

l

I

i

I

THE M.G. (Series MGA

Twin

Cam)

ENGINE

MGA (Twin Cam). Issue

1.

32403

I

j

;

j

!

I

i

I

i

j

I

i

I

:

i

!

~

I

i

I

l

.......

._....~

5

GENERAL

DATA

t:NGINE

Type

Number

of

cylinders

Bore

Stroke

Capacity

Firing order

Compression ratio

Capacity

of

combustion chamber (val

ves

fitted)

Valve

operation

B.M.E.P

...

Torque

Cooling system

Oversize

bore:

First

Maximum

CRANKSHAFI'

Main journal diameter

Crankpin journal diameter

Main

bearlnp

Number and type

Material (bottom half)

Material (top half)

Length

..

End-clearance

..

End-thrust

Running clearance

CONNECTING RODS

Length between centres

..

Big~ad

bearl~~p

Material (bottom half)

Material (top half)

Bearing side-clearance

Bearing diametrical

cl

earance

PISTONS

Type

Material

Clearances:

Bottom

of

skirt

Top of skirt

Type

Materi

al

Clearances:

Bottom

of

skirt

Top of skirt

PI

STON RINGS

Compression:

Top ring

Second and third rings

MGA

(Tw

in Cam).

Issue

4.

3

2403

BCI6GB.

4.

. . 2·969 in.

(75-41

mm.).

. . 3·5 in.

(89

mm.).

. .

96·906

cu. in.

(1588

c.c.).

I,

3,

4,

2.

9·9 : l with pistons AEH681.

8·3 : I with pistons

AEH690.

. .

86·6

c.c.

(5·28

cu. in.).

. . Twin overhead camshafts.

163

lb.Jsq. in.

(I

1-4

6

lcg

./cm.1)

at

4,500 r.p.m.

lOS

lb.

ft

. (14·5

kg.

m.)

at

4,500 r.p.m.

Thermo-siphon, pump- and fan-assisted.

. . -()JOin.

(·25

4

mm

.).

..

-040

in.

(Hll6

mm

.).

. . 2 in. (50-8

ro

m.).

1·8759

to

1·8764

in

.

(47-65

to

47-66

mm.).

. .

3.

Shell type.

. . Steel-backed, lead-indium· or lead-tin-plated.

. . Steel-backed, lead-ind

iu

m-

or

lead-tin-plated.

I Sia. (38 I

mus

.). (error) 1.

25

in.

(31.

75

mm)

·006

in. max. (·

152

mm

.).

.. Taken by tbrust washers

at

centre maio bearing.

-(}()2

to

·0037

in.

(.051

to

·094

rom.).

6·5 in.

(165-1

mm

.).

Steel-backed, lead-indium- or lead-tin-plated.

. . Steel-backed, lead-indium- or lead-tin-plated.

. .

·008

to

·012

in.

(·203

to

·305

mm.).

·002

to

·0037

in.

(·OS

I

to

·09

4 mm.).

. . Flat

top

(9·9

: I compression ratio).

. . Aluminium alloy.

. . ·

0035

to

-(}()66

in.

('

090

to

·

168

mm.).

. .

-(}()58

to

·0083

in

.

(·

14

7

to

·211

mm.).

Domed top (8·3 : I compression ratio).

. . Aluminium alloy.

·0035

to

·

0041

in. (·

090

to ·

101

mm.).

·0070

to

·0076

in. (·

177

to ·192 mm.).

. . Plain.

. . Tapered.

General Data I

GENERAL

DATA-continued

Width

..

Th

ickness

Fitted

gap

Clearance in

groov

e . .

Oil c

ontrol

type

..

(Fr

om Engine

No.

44

6)

Wi

dth

. .

Thickness

Fitted

gap

Clearance in

groove

GUDGEON

Type

Fit

..

Dia

met

er

VALVES

AND

VALVE

GEAR

Valves

Seat angle:

Inlet

..

Exhaust

H

ead

diamete

r:

Inlet

• .

Exhaust

Stem

diamete

r:

Inlet ••

Exhaust

Valve lift

Valve stem

to

guid

e clearance:

Inlet . .

Exhaust

Valve clearance

Chain

pitch

and

number

of pitches ••

Inlet valve:

Opens

Closes

Exhaust

valve:

Opens

Closes

VALVE

GUIDES

Length:

Inl

et

Exhaust

..

Di

amet

er:

Inlet:

Outs

ide

Ins

ide

Exhaust: Outside

Insi

de

Fitted height above

head:

Inl

et

Exhaust •.

General Data 2

. . ·0

54

to

·055

in.

(1

·

37

to I·

39

mm.).

. . ·

124

to

·131

in. (3-15

to

3·

33

mm

.).

.. ·

008

to ·013 in. (·20 to ·33 mm.).

. . ·0015

to

·0035

in

. (·038

to

·089 mm.).

. .

Microland

sc

raper

.

. . Twin-segment scraper.

. . ·1

552

to

·

1562

in.

(3

·

94

to

3

·9

9

mm

.).

. . ·1

24

to

·131 in. (3·

15

to 3

·33

mm.).

. . ·008

to

·013 in. (·20

to

·33

mm.).

. .

·001

5

to

·00

35

in. (·038 to ·089

mm.).

. . Fully floating.

Hand

-

push

fit

at

room

temperature.

·

875

in. (22

·22

mm.).

. .

1·59

in. (40·38 mm.).

1·

44

in. (36·58

rom

.).

•

342

in. (8·68 mm.).

·3

42

in. (8·68

mm

.).

·375

in

. (9·52 mm.).

. . ·00155 to ·00255

in.

(·0394 to ·0635

mm

.).

·00

155

to

·00255

in

. (·0394 to ·0635

mm.

).

·

01

4

to

·01

5 i

n.

(·356 to ·381

mm.)

(cold).

·3

75

in.

(9

·

52

mm.),

132

pitches.

20° B.T.

D.C

.

50°

A.B.D.C.

50°

B.B.D.C.

20°

A.T.D.C.

2-/r

in. (52·39

mm.

).

2-if in.

(61

·

91

mm.).

·5645

to

·

5655

in. (14·33

to

14

·36 mm.).

·3

438

to

·3

443

in.

(8

·73

to

8·74

mm

.).

·

5645

to

·5655 in. (14·33

to

14·

36

mm.).

·

343

8

to

·

3443

in.

(8

·

73

to

8·7

4

mm.).

·750 in. (

19-()5

mm.).

·

844

in. (21·43 mm.).

MGA (Twin Cam). Issue 4.

32403

GENERAL

DATA-continued

VALVE

SPRINGS

Free

length:

Inner

Outer

Fitted

length:

Inner

Outer

Number

of

working

coil

s:

Inner

Outer

Pressure:

Valve

open

Valve closed

TAPPETS

Type

Diameter:

Body

Working

face

Length

(From

Engine

No.

1087)

CAMSHAFIS

Journal

diameters

End-float

. .

Bearings:

number

and

type

Inside

diameter

..

Clearance

..

HALF-SPEED SHAFT

Journal

diameter

s:

Front

Centre

Rear

End-float . .

Bearings:

number

and

type

Inside

diameter

(reamed

in

position

):

Front

Centre

. .

Rear

Clearance . .

ENGINE

LUBRICATION

SYSTEM

Oil

pump

Type

Relief pressure valve

operate

s

Relief valve s

pring:

Fr

ee length

..

Fitt

ed le

ngth

Oil filter

Type

C

ap

a

cit

y

M

GA

(T

win

Cam). [

$SU

e

6.

32

403

2·3

in

. (58·42 rom.

).

2·54 in. (64·51

mm.).

. . 1·62

in

. (41-15 mm.).

1·78 in. (45·

21

mm

.

).

7·8.

6.

. .

Inner

65

lb. (29·5 kg.).

Outer

125 lb. (56·7

kg

.

).

. .

Inner

42

lb

. (19·1

kg

.).

Outer

84

lb.

(38·1

kg

.

).

. .

Inv

erte

d

bu

ck

et.

1·5 in. (38·1 mm.).

1·5 in. (38·1

mm

.).

. . 1

·2

5 in.

(31

·75

mm

.

).

. . 1·5

in

. (38·1 mm.).

1·

250

to

1·2505 in. (31·75 to

31

·76 mro.)

·001

to

·005 in. (·025 to ·127

mm

.

).

..

3.

D2

bi

-

metal

bearings.

. . 1·2515

to

1

·2

525

in.

(31·788

to

31-813 rom.).

. . ·001

to

-()()25

in. (·0254

to

·0635 mm.).

1·78875

to

1·78925

in

. (45·43

to

45·44

mm

.

).

1·

7287

5 to

1·72925

in

.

(4

3·

91

to

43·92

mm

.

).

1-62275

to

1·62325 in. (41·22

to

41·23

mm

.

).

·003

to

·

006

in

.

(·0

76

to

·

152

rom.).

. . 3. ThinwaU steel-backed white

metal

1·

7

90

in

. (45·47

mm

.).

1·730

in.

(4

3·94

mm.)

.

. . 1·624 in. (41·25

mm

.).

. .

-()01

to

·002 in. (·025

to

·051 mm.).

. . Eccentric

rotor.

. . 50 lb.fsq.

in

. (

3·

52 kg.f

cm

.2) .

. . 3 in. (76·2

mm

.).

..

2

1~

in

. (54·77 mm.)

at

16

lb. (7·26

kg

.)

load

.

. . External renewable elcmc:nt,

fuU

-fiow.

.. i pint (·6

U.

S.

pint

, ·28

litr

e)

.

General D

at

a 3

Oil

pr~ssure

Idling

Runn

ing

GENERAL

TORQUE WRENCH

SEITINGS

Cylinder head

nuts

Main

bearing

outs

Big-end

bearing

nut

s

Clutch assembly

to

flywheel

Camshaft

bearing

nut

Steering-wheel

nut

FUEL

SYSTEM

Carburettcr

Make

and

type

Diameter

Needle

..

J

et

Pi

sto

n

spring

..

AIR CLEANER

Make

and

type

FUEL

PUMP

Make

and

type:

Delivery test

Suction lift

Output

lift

COOUNG

SYSTEM

Type

Thermostat

setting

Quantity

of

anti-freeze:

15

° f

ro

st

25° frost

35° frost

IGNITION

SYSTEM

Sparking plugs

Size

Plug

gap

..

Coil

Distributor

contact

points gap

Suppressors

Static t

im

ing

:

9·1

: I compression

ra

tio

8·3 : 1 co

mpres

s

ion

ratio

CLUTCH

Make

and

type

Diam

eter

..

Facing material

General

Data

4

DATA

-

contin

u

ed

10

to

IS

lb.fsq. in. (·7

to

1·05 kg

.f

cm.

1

).

SO

to

60 lb./sq. in. (3·52 to 4·22 kg.fcm.1) .

. . 70

lb

. ft. (9·68

kg

. m.).

. . 70

lb

. ft. (9·68 kg. m.).

50

lb.

ft

. (6·913

kg

. m.).

. . 35

to

40

lb. ft. (4·84

to

5·53 kg.

iO

.).

33

lb. ft. (4·56 kg. m.).

. . 42 lb. ft. (5·15 kg. m.).

. .

S.

U. twin

H6

semi-downdraught.

It

in. (44·45 mm.).

. .

OA6

(standard).

RH

(rich).

OA7

(weak).

. . ·10 in. (2·54 mm.).

Red,

4i

oz. (128

gm.

).

Vokes,-oil-wetted.

S.U.

electric, large capacity.

12

·5 gal.fhr. (54·28 litresfhr.).

33 in. (83·8 em.).

48 in. (121·9 em.).

. . Pressurized

rad

ia

tor.

Thermo-siphon,

pump-

and

fan-assisted.

. . 50

to

55° C. (122

to

131° F.).

It

pints (

1-8

U.S. pints, ·85 litre).

. . 2 pints (2·4 U.S. pints, 1·14 litres).

.. 3i pints (4·2 U.S. pints, 2 1itres).

Champion

N3.

Champion

N58R

(for competition

work

and

other

arduous

conditions).

14

mm.

·025 in. (·64 mm.).

Lu

cas

HAI2.

Lucas, type

DM2

.P4.

·014

to

·016 in. (·35

to

·40

mm.)

.

Lucas No. 78106A fitted

on

each

H.T.

cable.

T.D.C.

8°

B.T

.

D.C.

Borg

& Beck

8ARG.

Single dry plate.

8 in. (20·3

em

.).

Wound

yam,

reinforced.

MGA (Twin Cam). Issue 6. 32403

GENERAL

DATA-continued

Pressure springs

..

Colour

..

Damper springs

Colour

..

Release lever ratios

GEARBOX

Number

of

forward speeds

Synchromesh

Ratio

s:

Top

Third

Second

..

First

Reverse

Overall ratios:

Top

'l'tird

Second

..

First

Reverse

Speedometer gea

rs

ratio

..

STEERING

Type

Steering wheel

turns-lock

to lock

Steering wheel diameter

..

Camber angle

Castor angle

King pin inclination

Toe-in

Track:

Front

Rear

FRONT SUSPENSION

Type

Spring detail:

Coil diameter (mean)

Diameter

of

wire

Free height

Number of free coils

Static laden length

at

load

of

Dampers

..

Damper settin

g!O:

Rebound:

Bl

ow-off

Time setting

Compression:

Bl

ow

-o

ff

Time setting . .

MGA (Twin Cam). Issue

3.

27765

6.

Light grey.

6.

Maroon

and

light green.

11·7:

1.

4.

Second, third,

and

fourth gears.

Standard Close ratio

gearbox gearbox

1

·0

:

1.

I·0 :

I.

1·374 :

1.

. . 2·214 : I.

..

3·64 :

I.

4·67 :

I.

4·3 :

I.

. . 5·908 :

l.

9·520 :

I.

15·652 :

1.

. .

20

·4

68

: I.

5/

12

.

. . Rack and pinion.

2j.

16! in. (419·10 mm.).

1·

267:1.

1·62 :

I.

2·

44

5:

I.

3·

199

:

I.

4·3 :

I.

5

·

44~

:

I.

6·9

66:

I.

10·52 :

I.

1

3·75:

1.

1° positive to

lo

negative

on

full bump.

4

o.

. . 9° to

tot

0

on

full bump.

Wheels parallel.

47ft

in. (1·217 m.).

. . 48! in.

(1

·242 m.).

. . Independent coil.

. . 3·28 in. (82·25 mm.).

. . ·54 in. (13·72 mm.).

. . 9·09 in. ±

nin.

(23·09

cm

.±

l·6 mm.).

..

7·2.

. . 6·6 in. (16·76 em.).

1,

19

3

lb

.

(5

41

kg.).

. . Piston type.

1,

150

lb. in. (13·3 kg. m.) at

18<'

0/sec.

at

18

° C.

72

5

lb

. in. (8·3 kg. m.)

at

20°/Sec.

at

18

° C.

55

0

lb

. in. (6·3 kg. m.)

at

1

80

°/Sec.

at

18°

C.

. . 3

50

lb

. in. (4·0 kg. m.)

at

20°/

Sec.

at

18

° C.

General D

ata

5

GENERAL

DATA-continued

REAR

SUSPE.~SION

Type

Spring detail:

Number

of

leaves

Width

of

leaves

Gauge

..

Working load

Free camber

Dampers

..

Damper settings:

Rebound:

Blow-off

Time setting

Compression:

Blow-off

Time setting

..

PROPELLER

SHAFf

Type

Make and

type

ofjoints

•.

Length between centres

of

joints (

fully

extended)

Overall length (fully extended)

..

Overall length (fully compressed)

Length between centres

of

joints (fully compressed)

..

Diameter

..

REAR

AXLE

Make and type . .

Ratio

Adjustment

ELECI'RICAL

EQUIPMENf

System

Charging

system

. .

Battery:

Type

(Export only)

..

Voltage

..

Capaci

ty

(20-hour rate)

Starter motor

Dynamo

..

Control box

Cut-out:

Cut-in voltage

..

Drop-offvoltage

Reverse current

Regulator:

At

1,500

r.p.m. dynamo speed:

. . Semi-elliptic.

•.

6.

..

lf

in.

(44·45

mm

.).

.. /r

in.

(5·56

mm..)

.

. .

4SO

lb.

(203·7

kg.).

. . 3·

60

in.

(91·44

mm

.

).

. . Piston type.

..

1,300

lb. in. (IS kg. m

.)

at

180°

/

sec.

at ts• C.

.•

175

lb. in.

(2·01

kg. m.) at

20°

/

sec.

at

ts• C.

..

400

lb. in. (4·6

kg.

m.)

at

tso•Jsec.

at ts•

C.

. .

17S

lb. in.

(2·01

kg

. m.) at

20°Jsec.

at

18°

C.

. . Tubular,

flanged.

. . Hardy Spicer. Needle roller.

..

30'!\

in.

{76·99

em

.).

. . 321t in.

(83-o

em.).

..

311

in.

(80·65

em.).

. .

29i

in.

(74·65

em.).

. . 2 in.

(50·8

mm.).

. . B.M.C.

"B'

type,

three-quarter-floating.

•.

10

/

43.

. .

Shims.

12-volt. Positive earth.

.. Compensated voltage control.

.. Lucas SG9E.

..

Lucas

STGZ9E (dry-charged).

. . 6-volt (2 off).

..

58

amp.

hr.

..

Lucas 4-brush

M35Gl.

Lucas

C39PV2

.

. . Lucas

RB106

/2.

. .

12·7

to

13·3.

..

8·Sto

11.

. . 5 amps. (max.).

Open circuit settingat

20"

C.

(68°

F.) . .

15

·4 to 1

6·4

volts.

For ambient temperatures other than

2(f

C. the

following

allowances should

be

made to the above setting:

For

every

100

C.

(lr

F.) above 20" C. subtract

·1

volt.

Forevery

100

C.

(18'"

F.)

below

20"

C.

acid

·1

volt.

OeneraJData6

MGA

(1WiD

Cam). Issue 3.

27765

GENERAL

OAT

A-continued

B~

Type

Disc

diameter

Auid

WHEELS

Type

TYRES

Size

Tyre

pressures:

Normal:

. . Dunlop disc (front

apd

rear).

..

11

in.

(27·9

em.).

. .

Wakefield

Crimsdn (S.A.E. 70.RI).

. • Ventilated disc;

4J

x

15.

•• 5·

90-15.

Front..

. .

18

lb./

sq

. in. (1·27 kg.f

cm

.1

).

Rear . . . . 20

lb

./sq.

in

. (1·4

kg

./cm.

1) .

Fa

st motoring:

Front

. . . . 22 lb.fsq. in.

(1·55

kg

./

cm.1

).

Rear . . . . 24

lb

./

sq

. in. (1·

69

kg./

cm

.1) .

Competition work

and

sustained high-speed motoring:

Front . . . .

24lb.

/sq. in. (1·69 kg./

cm

.2) .

Rear . . . . 2

6lb

./

sq. in. (1·83 kg.f

cm

.1) .

CAPACITIES

Engine

sump (includingfilter)

..

Gearbox ••

Rear axle •.

Cooling

system

..

Steering rack

Fuel

tank

. .

GENERAL DIMENSIONS

Wheelbase

Overall

length

Overall

width

Overall

height

Ground clearance. .

Turning circles:

Right

hand

Left hand

WEIGHTS

Imp.

u.s.

..

13

pt•

15

·6 pt.

..

4f

pt•

5·7

pt.

..

21

pt.

3•25

pt.

..

131

pt. 16·2 pt.

.. i pt. ·6 pt.

..

10

gal.

12

gal.

. • 94 in. (2·388 m.).

. •

156

in.

(3·962

m.).

••

S8

in. (1·473 m.).

••

SO

in.

(1·27

m.).

. . 6 in. (15·24

em

.).

••

32

ft. 1

in.

(9·78

m.).

32

ft

. 6

in

..

(9·91 m.).

Fully equipped with tools, spare wheel, oil, water, and 2

gallons

(2

·5 U.

S.

gal

., 9·1 litres) of

fuel

..

2,185

lb.

(991

kg.).

Engine

(dry) . . 414

lb.

(188

kg.) approx.

Gearbox (dry) •. 69lb.

(31

kg.) approx.

Rear axle (dry) . . . .

137

lb.

(62

kg.) approx.

MGA (Twin Cam). Issue 3. 32403

Lilres

7·38

2·69

1·56

7·7

·28

45

·4

General Data 7

CONTROLS

Hand brake

GENERAL

INFORMATION

The

hand

brake lever

is

located alongside the driver's seat

and

operates on the

rear

disc brakes only by means

of

separately

mounted

calipers.

To

operate, pull

up

the lever

and

press the

knob

in the end with the

thumb

to

lock the lever in position.

To

release

the brakes pull upwards

on

the lever

to

automatically release the lock

and

then

push

downwards.

Always apply the

hand

brake when parking.

Brake pedal

The pedal operates the hydraulic disc brakes on all four wheels

and

will also operate the twin stop warning lamps

when the ignition

is

switched on.

The location

of

the driving controls

I.

Bonnet release.

5.

Clutch pedal. 8.

Hand

brake lever.

2.

Gear

lever.

6.

Accelerator. 9.

Foot

brake.

3. Gearbox oil filler plug.

7.

Seat lock.

10.

Seat lock.

4. Headlamp dip switch.

Gear lever

The

four

forward gears

and

the reverse gear are engaged by moving the lever

to

the positions indicated

in

the

illustration.

To

engage the reverse gear move the lever

to

the left

of

the neutral position until resistance

is

felt, apply side pressure

to the lever

to

overcome the resistance,

and

then pull it backwards

to

engage the gear.

Synchromesh engagement

is

provided

on

second, third,

and

fourth gears.

Seat

adjustment

A lever is provided

at

the front

of

each seat

and

this must be pressed outwards

to

release the catches

and

allow the

seat

to

slide.

General Information 1

GENERAL

INFORMATION

continued

Steering column adjustment

A steering column which

is

adjustable for length

is

available as an optional extra. This enables the steering wheel

to be placed in the most comfortable driving position after slackening a clamp bolt below the wheel hub. Always re-

tighten the nut securely after adjustment.

Headlamp beam

dip

switch

This

is

situated on the left

of

the clutch pedal and

is

foot-operated. The switch

will

dip the headlamp beams on one

depression and raise them on the next.

Bonnet lock release

The bonnet

is

hinged

at

the rear and the lock

is

released

by

pulling on the ring below the instrument panel on the

extreme left-hand side

of

the car.

The bonnet

is

still held by the safety catch, which must

be

released before the bonnet can be raised.

To

re-lock the bonnet in the fully closed position after opening, press downwards on the front

of

the bonnet until

the lock

is

heard to engage.

INSTRUMENT

PANEL

Speedometer

The speedometer also records the trip and total distances. The trip recorder

is

reset to zero by pushing upwardii

the knob below the instrument and turning it anti-clockwjse.

The right-hand side

of

the instrument panel (R.H.D.)

I. Hcadlamp

and

sidelamp switch.

9.

Starter

switch.

"

Fog

lamp switch. 10. Water temperature gauge.

3.

Oil gauge.

II.

Revolution indicator.

4. Panel light switch. 12. Ignition warning light.

5.

Speedometer.

13.

Headlamp beam warning light.

6.

Trip

mileage. 14.

Total

mileage.

7. Flasher warning light. 15. Direction indicator switch.

8.

Horn

button.

Main beam warning light

The warning light at the bottom

of

the speedometer dial glows red when the headlamp main beams are in use

as

a

reminder to dip the beam when approaching other traffic.

Engine revolution indicator

This dial

is

calibrated in hundreds

of

revolutions per minute. Normal use

of

the engine will not require speeds over

6,000 r.p.m.

and

great care must be taken if the needle does approach the amber sector

of

the dial, which commences

at 6,500 r.p.m. Under favourable conditions the needle may be allowed to enter the amber sector, but under

no

circum-

stances must

it

enter the red sector.

General Information 2

GENERAL

INFORMATION

continued

Ignition warning light

The warning light

at

the bottom

of

the revolution indicator dial glows red when the ignition

is

switched on

and

will

go

out

again when the engine is started

and

its speed

is

increased sufficiently for the dynamo to charge the battery.

Should the light glow

at

all engine speeds, the dynamo is

not

charging the battery.

Oil pressure gauge

The pressure

of

the oil should be between 30

and

80 lb./sq. in.

(2·1

and

5·6 kg./cm.2) under normal running con-

ditions. Approximately 10 lb./sq. in. (·7 kg./cm.2) should be shown when the engine

is

idling.

Water temperature gauge

The temperature

of

the cooling water leaving the cylinder head

is

indicated by this gauge

and

should

be

approxi-

mately 160° F.

(7lo

C.) when the engine

is

running normally.

Starter

switch

Pull out the

knob

marked

'S'

to operate the starter motor. The switch must be pushed in immediately the engine

starts.

Lamp switch

To

switch

on

the sidelamps, tail lamps, and number-plate illumination lamp pull out the knob marked

'L'.

Turn

the

knob

clockwise

and

pull

out

again to switch

on

the headlamps.

See 'Headlamp beam dip switch'

and

'Main

beam warning light'.

The left-hand side

of

the instrument panel (R.H.D.)

1.

Map-reading light switch.

5.

Windshield washer control.

2.

Windshield wiper switch. 6. Fuel gauge.

3.

Ignition switch.

7.

Choke control.

4. Map-reading light. 8.

Horn

button.

Fog lamp switch

A fog lamp is

not

fitted as standard equipment,

but

the switch marked

'F'

on

the instrument panel

is

connected to

the battery

and

is

ready for use when a fog lamp

is

connected to it.

Pull

out

the

knob

to switch on the fog lamp.

Panel lamp switch

To

illuminate the instruments turn the control

knob

'P'

clockwise. The first movement

of

the

knob

will

switch on

the lamps

and

further turning

to

the right will dim the lamps.

The

panel lamps will only operate when the sidelamps also are switched on.

General Information 3

GENERAL

INFORMATION

continued

Direction indicator switch

The

lever-type switch

on

the

outer

edge

of

the

panel

controls

the flashing

indicator

unit.

The

unit

will

operate

only

while the ignition is switched on,

and

flashes the sidelamp

and

tail

lamp

on

the side

of

the

car

to

which the switch lever

is

moved

until

it

is automatically switched off.

While the flashing

unit

is switched on the warning light next to the switch will show green.

Fuel gauge

This operates only when

the

ignition is switched on.

Choke

or

mixture control

To

enrich

the

mixture

and

assist starting when the engine is cold pull

out

the

knob

marked

'C'

and

lock it in position

by

turning

it

anti-clockwise.

Turn

the

knob

clockwise

and

push

it inwards

to

the

normal

running

position

as

soon

as the

engine is

warm

enough

to

run

without

the rich mixture.

Never allow the engine to run for

any

length

of

time with

the

knob

pulled out.

Ignition switch

The

fuel

pump

and

gauge are

brought

into

action by this switch, which is also the master switch for

the

windshield

wipers

and

direction indicators.

Windshield wiper switch

The

windshield wipers are self-parking

and

operate only when the ignition is switched on.

Pull

out

the

control

'W'

to

set the wiper blades in motion.

Push

in the

knob

to switch

off

the

motor

and

park

the

blades.

Map-reading lamp

The

map-reading

lamp

is controlled by the adjacent knob, which must be pulled

out

to

switch

on

the light.

The

lamp

will only operate while the sidelamps are switched on.

Windshield washer

When

windshield-washing

equipment

is fitted

it

is

operated

by

the

knob

marked

'Push'

below the fuel gauge.

HEATING AND DEMISTING

EQUIPMENT

The

2·75-kw. heating

and

demisting

unit

is fitted as

an

extra

to

standard

equipment.

Fresh

air

is

ducted

from the

radiator

grille

to

the

heating

element

and

blower

motor

mounted

bdow

the

bonnet.

Water

from the engine cooling system

is

used to heat the element.

Warmed

air

issues from the

toeboard

or

the windshield demisting vents according

to

the position

of

the

controls

mounted

below the instrument panel.

Air

The

left-hand

knob

controls the

air

supply. When the

knob

is

pushed

in the

air

duct

is

open

and

air

at

atmospheric

temperature will enter

the

car

when it

is

in motion

and

will issue from the

toeboard

or

demisting vents.

Air blower

Pull

out

the

knob

marked

'B'

on

the

temperature

control

lever

to

switch

on

the blower

motor,

and

this will increase

the flow

of

air

into

the

car

and

may be used

to

give a

supply

of

air

when the

car

is

stationary

or

travelling

at

low

speed.

The

blower will only

operate

when the ignition is switched on.

If

the blower

motor

is switched

otT

and

the air

control

knob

is pulled

outwards

to

close the

air

duct

fresh

air

cannot

enter

the

car

from the

toeboard

or

windshield vents.

General

Information

4

GENERAL

INFORMATION-continued

De

mist

The right-hand knob on the heater unit control panel operates a shutter in the panel above the gearbox cover.

When the control

is

pushed into the normal position the shutter is open and most

of

the air from the unit will enter the

car

at

the toeboard, while some will issue from the vents below the windshield.

As

the knob

is

pulled out the shutter

closes

and

more air

is

delivered to the car from the demisting vents, giving the maximum supply

of

air to the windshield.

This

is

the demist position

of

the control if the blower is switched on and also the defrost position if the heater

is

operating.

Temperature

The temperature lever operates the water valve on the engine. When the lever is in the left-hand position the hot

water supply is cut off and air entering the car through the unit will not

be

heated.

As

the lever

is

moved to the right

the water supply

is

increased and the maximum temperature

is

obtained.

COLDA'R

INLET

(j) AIR

COLD

AIR

INLET

@AiR

c)

COLD

.WARM

.HOT

SYMBOLS

BLOWER

BOOSTER

PULL

PUL~

.-HOT

WATE"l

INLET

"'

CLOSED

t \ "

I

BLOWER

BOOSTER-PULL

The circulation

of

the air through the heater unit with the controls positioned as recommended below

As

a general guide, here are some

of

the more frequently required positions:

No

additional

ventilation

or

heating.

Pull out the air control, push the temperature control to the left.

(1)

Hot weather. Push in the air and demist controls. Move the temperature control to the left. To increase the

supply

of

air switch on the blower motor.

(2)

Warm weather. Set the controls as for hot weather. To increase the supply

of

air switch on the blower motor.

To prevent mist forming on the windshield pull

out

the demist control partially.

(3)

Cold weather. Place the air control in its normal position and the temperature lever according

to

the heating

required. Switch on the blower to increase the air supply.

(If

demisting

is

required pull out the demist control.)

(4)

Severe cold. Move the temperature control

to

the right for maximum heating and pull out the demist control

fully

to

give a maximum supply

of

hot

air

to

the screen. Switch on the blower motor to increase the air flow.

MGA (Twin Cam). Issue

2.

23026

General Information 5

GENERAL

INFORMATION

continued

WINDSHIELD WASHER

The washing equipment supplied as an optional fitting

is

operated by pumping the knob

on

the instrument

panel. As the knob moves towards the panel a jet

of

cleaning fluid is ejected onto the windshield from nozzles

on the scuttle.

Set the windshield wipers

in

motion before operating

the cleaning jets.

Fluid for the windshield

is

stored in an unbreakable

bottle clipped to the engine bulkhead. When refilling

with fluid lift the bottle from its clip and unscrew the cap.

FOLDING

THE

HOOD

Never fold the hood

if

it is wet

or

damp;

wait until

it

is

dry.

(1)

Release the hood from the pillars

at

the top

of

the windshield by unscrewing the wing bolts.

(2)

Release the rear bottom edge

of

the hood from

the three buttons and the turnbuckle at each

Operating the

;•,oindshield

washer

side. Pull on the centre knob

of

each button to release them from their attachment pins.

(3)

Raise the front

of

the hood slightly

to

release the tension in the canvas, and pull to the rear the bottom

of

the

hood where it

is

attached

to

the tonneau panel to release it from the two anchor brackets on the panel.

(4) Tip the seats forward, unfasten the sidescreen container, and turn it over onto the tonneau panel to expose

the hood stowage compartment.

(5)

Leave the rear window panel suspended over the tonneau panel and collapse the hood into the stowage com-

partment, pulling the canvas clear

of

the hood irons and folding it forward over the front hood rail.

(6)

Fold the rear window forward over the hood, pu1ling out the spare canvas at each side

and

folding it neatly

over the front

of

the window.

(7)

Push the hood into the stowage compartment

and

turn the sidescreen container forward to cover the hood.

(8)

Remove the sidescreens and stow them in the container pockets with the cranked bracket

of

each screen at

opposite ends and facing towards the rear.

(9) Secure the sidescreen container over the folded hood with the

six

buttons (three on each side).

(10) Tighten the sidescreen clamping nut on each door to prevent its possible loss.

OPTIONAL FITTINGS

The following items

of

equipment arc available as optional fittings:

Tonneau cover. Competition windshield assembly.

Radiator blind. Luggage carrier.

Heating and demisting equipment. Wing driving mirror.

Twin horns. Cold air ventilation kit.

Fog lamps. Ashtray.

Cigar lighter. Badge bar.

H.M.V. car radio (provision has been made Sun visors (Coupe only).

for easy installation). Adjustable telescopic steering column.

Windshield washer. Competition de-luxe seats.

Detachable hard-top. Close-ratio gearbox.

Sliding windows.

SERIAL NUMBERS

The major components

of

the vehicle have serial numbers and these will be found in the positions illustrated on the

opposite page. When in communication with the Company

or

your Dealer always quote the engine number and car

number complete with prefixes. The registration number is

of

no assistance and is

not

required. Write your name

and

address clearly.

General Information 6

MGA

(Twin Cam). Issue

2.

23026

GENERAL

INFORMATION

continued

Chassis number. This is stamped

on

the identification

plate and should be quoted with its prefix. The plate

is secured to the top left-hand side

of

the

dash

panel

Gearbox Number. Stamped on

top

of

the gearbox

casing adjacent to the dipstick

Engine Number. Stamped

on

a plate at the rear (if

the engine behind the cylinder block

Bo(~J'

Number. Stamped

on

a plate secured

to

the

right-hand side olthe

dash

panel

Rear Axle Number. Stamped

on

the ji"ont

of

the left-

hand rear axle tube

General Information 7

GENERAL

INFORMATION-continued

POWER

UNIT

SERIAL NUMBER

CODING

The

engine

number

on

later

engines comprises a series

of

letters and numbers, presenting in code the capacity

make,

and

type

of

unit. ancillaries fitted,

and

the type

of

compression together with the serial

number

of

the unit.

1st PREFIX

GROUP-Cubic

capacity, make, and type

1st Prefix

number

8-803

c.c.

9~950

c.c.

12-1200

c.c.

15~1500

c.c.

16--1600 c.c.

22~2200

c.c.

25~2500

c.c.

26-2600

c.c.

Ist Prefix letter

B~B.M.C.

Industrials

G-M.G.

H-Miscellaneous

special

J-Commercial

M~Morris

R-Riley

W-Wolseley

2nd Prefix letter

A-Z

used for the variations

of

engine type

2nd PREFIX

GROUP-Gearbox

and Ancillaries

A~Automatic

gearbox

M-Manumatic

clutch

N~Steering

column gear change gearbox

0-0verdrivc

(Borg-Warner)

P-Police

specification

U~Centre

gear change gearbox

3rd

GROUP-Compression

and serial number

H-High

compression I

J and serial

number

of

unit

L-Low

compression

CODE

EXAMPLE

16G/U/123456

General Information 8

Number

Gear

Change

Gearbox

c.c.

'MGA'

MG MGA Twin Cam Instruction manual

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