MG MGB Instruction manual

MW
Workshop Manual
Publication Part No. AKD 3259 (14th Edition)
@
Leyland Cars—service
Cowley, Oxford OX4 2PG, England

MGB.
Introduction
Maintenance
Lubrication Chart
General Data
Engine Tuning Data
Engine
Engine (Local and territorial requirements) ..
Ignition System
Cooling System
Fuel System
Fuel System (Evaporative Loss) ..
Clutch
Gearbox ..
Overdrive
Gearbox (All Synchromesh)
Overdrive (Type L.H )
Automatic Gearbox ..
Propeller Shaft ,
Rear Axle and Rear Suspension (Three-quarter-■oating Type) ..
Rear Axle and Rear Suspension (Semi-■oating Type)
Steering Gear ..
Steering Gear (Energy Absorbing Column)
Front Suspension
Hydraulic Dampers ..
Braking System
Braking System (Tandem Master Cylinder)
Electrical System
Electrical System (Local and Territorial Requirements) ..
Wiring Diagrams
Wheels and Tyres
Body
Body (Local and Territorial Requirements) ..
Service Tools ..
Recommended Lubricants ..
Issue 3. 86842
CONTENTS
A” ’0 5546*» £93
18 DIAMOND «
b».
Na'lghurw‘,
PORT 06 1
as} 572?“,
Specialist repairs to Land R
M“ and repairs to an mom ‘Range Rover
“as ‘MOT Sumon
.A
.Aa
.Da
.Fa
.Fb
.Fc
.Fd
.Ha
.Ja
l“
.End of Manual

MAINTENANCE SUMMARY
R.H.D. and L.H.D. except North America—continued
ACTION
OPERATION X
E: 8
on n
Re■tengine drain plug
Re■tgearbox drain plug
Re■tgearbox drain plug (every 24,000 miles)
Paint timing marks (early models)
Lower lift
Fit exhaust extractor pipe
Renew engine oil ■lter
Check/ top up gearbox oil
Fill gearbox with oil
Fill gearbox with oil (every 24,000 miles)
Check/adjust torque of cylinder head nuts
Check/adjust torque of rocker shaft nuts
Check/adjust torque of manifold nuts
Check/ adjust valve clearances
Fill engine with oil
XCheck/ top up engine oil
Lubricate water pump (early models only)
Lubricate dynamo bearing (early models only)
Top up carburetter piston dampers
Lubricate accelerator control, linkage and pedal pivot
Renew air cleaner elements
Check security of accessible engine mountings
Check driving belts, adjust or renew
Clean/adjust spark plugs
Renew spark plugs
Clean and test crankcase breather valve
Check/ top up clutch ■uid reservoir
Check/ top up brake ■uid reservoir
Check/ top up windscreen washer reservoir
Check/top up cooling system
Renew fuel line filter
Clean brake servo ■lter
Check cooling and heater systems for leaks
Run engine and check sealing of ■lter, stop engine
Rechec‘k/ top up engine oil
Connect instruments and check data
Check/adjust distributor points, renew if necessary
Check volt drop between coil CB and earth
Lubricate distributor
Run engine
Disconnect vacuum pipe, check dwell angle, adjust points as
necessary Using electronic
Check stroboscopic ignition timing equipment
Check distributor automatic advance
Check advance increase as vacuum pipe is reconnected
Check throttle operation, check/adjust carburetter idle speed
and mixture settings
Check/ top up automatic gearbox ■uid
Stop engine
0Remove wing covers
XXOOQ
xxoooo .
O
><><><><>< X
X
XX X
XX XXX
><><><><><
XX
XX
X X
XXXX
XXXX
XXXX
><
X.><><><.><.><><><><><><><><><
X.><><><.><
X.><><><.><.><
><><><><
><><><>< ><><><><
0.x
0.x 0.x
~Maintenance 2" MGB. Issue2. 86842

MAINTENANCE SUMMARY
R.H.D. and L.H.D. except North America—continued
After
Sales
>
ACTION
U!
OPERATION x
Oxxxx .0 Ox
x.
X
.XXXXXXX..X..><
><><><><><.><><
Lubricate all locks and hinges (not steering lock)
Fill in details and fix appropriate Unipart underbonnet stickers
Close bonnet
Check and if necessary renew windscreen wiper blades
Remove exhaust extractor pipe
Remove spare wheel
Check spare tyre complies with manufacturer’s speci■cation
Check depth of tread
Check visually for external cuts in tyre fabric
Check visually for external exposure of ply or cord
Check visually for external lumps or bulges
Check/adjust tyre pressure
Check fuel filler pipe connections
Refit spare wheel. Drive car off lift. Remove rear compartment floor covering and
access panel
Check/ top up battery electrolyte
Clean and grease battery connections
Re■trear compartment floor covering and access panel
Check/ adjust headlamp alignment
Check/ adjust front wheel alignment
Carry out road or roller test and check function of all instrumentation
Report and additional work required
Ensure cleanliness of controls, door handles, steering wheel, etc
Oxxxxxxx00x00x O><><><><><><><O x.
X
X.
X
X
xxxxxOxx
This Maintenance Summary was produced from Leycare Supplementary Job Sheet AKD 8469 (1st Edition). Job sheets used
by British Leyland Distributors and Dealers operating Leycare Service are updated as modi■cations affecting routine
maintenance are introduced and the content of this maintenance summary may differ from that currently used by Leycare
Service operatives.
MGB. Issue2.
,“Paed‘r
awarez■"‘
EET (052W n"
lgméxg■gzi¥bcxponv”b‘ ’
H
0‘
."-2
M187
—
RAHQe‘",
dRovel O1 $331K”
Lan
‘0 akes‘
airs
r80 rs‘o an m
.
\d rep?“
Service 3‘
86842 Maintenance 3

MAINTENANCE SUMMARY
NORTH AMERICA
The following items should be checked weekly by the driver:
Engine oil level
Brake ■uid level
Battery electrolyte level
Radiator coolant level
Windshield washer reservoir level
All tyre pressures
All lights for operation
Horn operation
Windshield wipers operation
MAINTENANCE INTERVALS
TThese items are emission related
Carry out the services indicated by Xin column
The Lubrication Service at 3,000-mile or 3-month intervals Lubrication
Aat 6,000—mile or 6-month intervals Service AB
Bat 12,000-mile or 12-month intervals
*Speci■ed otherwise
LUBRICATION
Lubricate all points .................................................................................................................... ..X ............... ..X .........
Renew engine oil ......................................................................................................................... ..X ............... ..X .........
Renew engine oil ■lter ..................................................................................................................................... ..X .........
Check level of all ■uid reservoirs, brake, clutch, battery, rear axle, transmission,
cooling system and windshield washer ................................................................................. “X ............... “X ..........
ENGINE
TCheck all drive belts; adjust if necessary .....................................................................................................................
TCheck all hoses, vacuum, air and water for condition and tightness ......................................................................... H
TRenew all air ■lter cleaner elements (air pump and carburetter) ................................................................................ ..
TCheck restrictor in rocker cover purge line for obstruction ......................................................................................
TAdjust valve rocker clearances ...................................................................................................................... “X .........
TCheck gulp valve operation (renew if necessary) .........................................................................................................
FUEL SYSTEM
TRenew fuel line ■lter .......................................................................................................................................................
TCheck condition of fuel ■ller cap seal ............................................................................................................................
TCheck fuel pipes and unions for cha■ng, corrosion and leaks ..................................................................................
TTop up carburetter piston dampers ................................................................................................................ ..X ..........
OSCILLOSCOPE AND COMBUSTION CHECK
TCheck distributor points, resistance and dwell .............................................................................................. ..X ......... ..
TRenew distributor points .................................................................................................................................................. .n
TCheck ignition timing and distributor advance or retard characteristics .................................................. ,.X .........
TCheck engine idle speed... ................................................................................................................................. “X .........
TCheck spark plugs (cruise and unload condition) ........................................................................................ ..X .........
TRenew spark plugs ...........................................................................................................................................................
TCheck distributor cap and wires ...................................................................................................................... ..X .........
Check charging system output ........................................................................................................................ ..X .........
TPower check, engine cylinder comparison ...................................................................................................................
TCheck choke and carburetter fast idle speed setting .................................................................................... ..X .........
TCheck exhaust emission (CO HC) at idle ...................................................................................................... ..X .........
MGB. Issue2. 86842
.Maintenance 4

MAINTENANCE ‘SUMMARY
North America—continued
‘
A B
SAFETY .
Check/adjust front wheel alignment ..............................................................................................................................
Check visually hydraulic pipes, unions for cha■ng, leaks and corrosion ................................................................
Check/adjust handbrake operation ............................................................................................................. .. A...X .........
Inspect the brake pads for wear and discs for condition ......................................................................... .. ....X .................. ..
Inspect brake linings and pads for wear, drums and discs for condition ................................................................
Check/adjust headlights ................................................................. ........................................................... .. .WX .........
Check tyres visually, and report depth of tread, cuts in fabric, exposure of ply or cord structure,
lumps or bulges ......................................................................................................................................... .. ....X .........
Check wiper blades for condition .................................................................................................................................
Check condition, operation and security of seats, seat belts/interlock ....................................................................
Check operation of all door locks and window controls ............................................................................................
ROAD TEST
Ensure that operation of vehicle is satisfactory and report all items requiring attention ................... .. ....X .........
24,000—miles or 24-month intervals
*TRenew all drive belts
*TCheck air pump (correct or renew if necessary)
*TRenew adsorption canister
*TRenew distributor cap and wires
* Clean overdrive ■lter
36,000—miles or 36-month intervals
*Renew all hydraulic brake seals
The maintenance summary on this and the preceding page is the minimum service required to maintain your vehicle
under normal driving conditions. For other than normal driving conditions, and those caused by seasonal changes,
we recommend that you consult your Dealer.
MGB. Issue 1. 86842 MaintenanceS ‘
.A

LUBRICATION CHART
R.H.D. and L.H.D. EXCEPT NORTH AMERICA
U
IND23IB
NOTEz—Ensure
that the vehicle is standing on alevel surfacewhen checking the oil levels.
Weekly
(1) ENGINE. Check oil level, and top up if necessary.
Every 6,000 miles or 6months
(2)
(3)
(4)
(5)
ENGINE. Drain and re■ll with new oil.
ENGINE OIL FILTER. Remove the disposable cartridge, fit
new.
Early cars: Drain filter, wash ■lter bowl in fuel and fit new
element.
CARBURETTERS. Top up carburetter piston dampers.
ACCELERATOR. Lubricate accelerator control linkage, cable
and pedal fulcrum.
DISTRIBUTOR. Lubricate all parts asnecessary.
REAR AXLE. Check oil level, and top up if necessary.
GEARBOX AND OVERDRIVE. Check oil level, and top up
if necessary.
(9)
(10)
(11)
(12)
AUTOMATIC TRANSMISSION. Check fluid level, and top
up if necessary. .
FRONT SUSPENSION (6 nipples)
HAND BRAKE CABLE (1 nipple) .
AND MECHANICAL LINKAGE “mm W“ a
PROPELLER SHAFT (1 nipple) grease
gun-
LOCKS AND HINGES. Lubricate the bonnet releasesafety
catch and all looks and hinges.
Give three or four
Every 24,000 miles or 24 months
(13) GEARBOX WITH OVERDRIVE. Drain, clean overdrive
filters and refill with new oil.
Optional lubrication at 3,000 miles 01’3months
(1) ENGINE. Check oil level and top up if necessary.
Recommendedoils and greasesaregiven at the end of the manual
MGB. Issue1. 86842

LUBRICATION CHART
NORTH AMERICA
IND23|E
NOTE :—Ensure that the vehicle is standing on alevel surface when checking the oil levels.
Weekly
(1) ENGINE. Check oil level, and top up if necessary.
Lubrication service every 3,000 miles or 3 months
(2) ENGINE. Drain and re■ll with new oil.
(3) THROTTLE AND CHOKE. Lubricate throttle and
choke control linkages, cables, and accelerator pedal
fulcrum.
(4) REAR AXLE. Check oil level, and top up if necessary.
(5) GEARBOX AND OVERDRIVE. Check oil level, and
top up if necessary. ‘
(6) PROPELLER SHAFT (l nipple) Give three or four
(7) FRONT SUSPENSION (6 nipples) strokes with a
(8) HAND BRAKE CABLE (l nipple) grease gun.
(9) WHEELS AND HUBS. Lubricate wire wheel and hub
splines.
Recommended oils and greases are given at the end of the manual I"
~.
3‘ '.
MGB. Issue1. 86842
LOCKS, HINGES AND LINKAGES. Lubricate all
door, bonnet and boot locks and hinges; and the hand
brake mechanical linkage.
FRICTION POINTS. Spray lubricant on all friction
points. .r
‘A’ service every 6,000 miles or 6 months; AND ‘3’ service
every 12,000 miles or 12 months
(10) ENGINE OIL FILTER. Remove disposable cartridge,
■tnew. '-'i
(11) CARBURETTERS. Top up carburetter piston dampers.
(12) DISTRIBUTOR. Lubricate all parts as necessary.
Every 24,000 miles or 24 months ‘..
(13) GEARBOX WITHOVERDRJVE. Drain, clean over-
drive ■lter, re■ll with new oil. "- ~.
Maintenance 7

ENGINE
Type .. .. ..
Number of cylinders ..
Bore
Stroke _..
Capacity .. ..
Combustion chamber volume (valves fitted) ..
Firing order
Valve operation ..
Compression ratio: H.C. ..
LC. ..
Compression pressure: H.C.
L.C.
Torque: H.C. ..
L.C. ..
Engine idle speed (approx.)
Oversize bore: First ..
Max. ..
Crankshaft
Main journal diameter
Crankpin journal diameter ..
Crankshaft end-thrust
Crankshaft end-■oat
Main bearings
Number and type
Material .. ..
Length .. .. ..
Diametrical clearance
Undersizes
Connecting rods
Type .. .. ..
Length between centres
Big-end bearings
Type
Material .. ...
Length .. .. ..
Diametrical clearance
Undersizes
End-■oat on crankpin (nominal) ..
Pistons
Type .. .. .. ..
Clearance in cylinder: Top
Bottom ..
Number of rings ..
Width of ring grooves: Top ..
Second ..
Third
Oil control
Gudgeon pin bore
MGB. Issue7. 80619
GENERAL DATA
(18G/18GA)
18G, 18GA.
4.
3.16 in. (80.26 mm).
3.5 in. (89 mm.).
1798 c.c. (109.8 cu. in.).
42.5 to 43.5 c.c. (2.59 to 2.65 cu. in.).
1, 3, 4, 2.
Overhead by push-rod.
8.8 :1.
8.0 :1.
160 lb./sq. in. (11.25 kg./cm.2).
1301b./sq. in. (9.15 kg./cm.2).
1101b. ft. (15.2 kg.m.) at 3,000 r.p.m.
105 lb. ft. (14.5 kg.m.) at 3,000 r.p.m.
500 r.p.m.
.010 in. (.254 mm.).
.040 in. (1.016 mm.).
2.1262 to 2.127 in. (54.01 to 54.02 mm.).
1.8759 to 1.8764 in. (47.648 to 47.661 mm.).
Taken on thrust washers at centre main bearing.
.004 to .005 in. (.10 to .13 mm.).
Three thinwall.
Steel-backed copper-lead.
1%in. (28.5 mm.).
.001 to .0027 in. (.0254 to .068 mm.).
—.010,~.020, —.030 and —.040 in. (—.254, «.508,
—.762 and «1.016 mm.).
Angular-split big-end, split clamp small-end.
6.5 in. (165.1 mm.).
Shell.
Steel-backed copper-lead.
.995 to 1.005 in. (25.2 to 25.52 mm.).
.001 to .0027 in. (.0254 to .068 mm.).
—.010,—.020, —.030 and —.040 in. (—.254,_—.508,
—.762 and —1.016 mm.).
.008 to .012 in. (.20 to .30 mm.).
Aluminium solid skirt.
.0036 to .0045 in. (.091 to .121 mm.).
.0018 to .0024 in. (.045 to .060 mm.).
4(3 compression, 1'oil control).
.064 to .065 in. (1.625 to 1.651 mm.).
.1578 to .1588 in. (4.008 to 4.033 mm.).
.7501 to .7503 in. (19.052 to_“19.057 mm.).
GeneralData 1

GENERAL DATA—continued
(lSG/lSGA—continued)
Piston rings
COMPRESSION
Type: Top .. .. ..
Second and third
Width: Top .. ..
Second and thir
Fitted gap: Top .. .. ..
Second and third ..
Ring to groove clearance: Top .. ..
Second and third
OIL CONTROL
Type ..
Width .. ..
Fitted gap .. .. ..
Ring to groove clearance
Gudgeon pin
Type
Fit in piston
Diameter (outer)
Camshaft
Journal diameters: Front
Centre
Rear ..
. . . . . Front
Bearmg liner 1n81dedlameter
(reamed after fitting): centre
Rear
Diametrical clearance
End-thrust
End-■oat
Cam lift ..
Drive ..
Timing chain ..
Tappets
Type .. ..
Outside diamete
Length ..
Rocker gear
ROCKER SHAFT
Length
Diameter
ROCKER ARM
Bore .. .. .. ..
Rocker arm bush inside diameter
Ratio ..
Valves
Seat angle: Inlet and exhaust
Head diameter: Inlet
Exhaust ..
Stem diameter: Inlet
Exhaust ..
Stem to guide clearance: Inlet ..
Exhaust
Valve lift: Inlet and exhaust
GeneralData 2
.«1
Parallel 1
Tapered J
.0615 to .0625 in. (1.562 to 1.587 mm.).
cast iron—molybdenum filled.
.012 to .017 in. (.304 to .431 mm.).
1.0015 to .0035 in. (.038 to .088 mm.).
Slotted scraper.
.1552 to .1562 in. (3.94 to 3.96 mm.).
.012 to .017 in. (.304 to .431 mm.).
.0016 to .0036 in. (.04 to .09 mm.).
Semi-■oating.
Free-fit at 20°C. (68 °F.).
.7499 to .7501 in. (19.04 to 19.05 mm.).
1.78875 to 1.78925 in. (45.424 to 45.437 mm.).
1.72875 to 1.72925 in. (43.910 to 43.923 mm.).
1.62275 to 1.62325 in. (41.218 to 41.230 mm.).
1.79025 to 1.79075 in. (45.472 to 45.485 mm.).
1.73025 to 1.73075 in. (43.948 to 43.961 mm.).
1.62425 to 1.62475 in. (41.256 to 41.269 mm.).
.001 to .002 in. (.0254 to .0508 mm.).
Taken on locating plate.
.003 to .007 in. (.076 to .178 mm.).
.250 in. (6.35 mm.).
Chain and sprocket from crankshaft.
%in. (9.52 mm.). pitch x52 pitches.
Barrel with ■at base.
1%in. (20.64 mm.).
2.293 to 2.303 in. (58.25 to 58.5 mm.).
143% in. (.356 mm.).
.624 to .625 in. (15.85 to 15.87 mm.).
.7485 to .7495 in. (19.01 to 19.26 mm.).
.6255 to .626 in. (15.8 to 15.9 mm.).
1.4 :1.
451/24).
1.562 to 1.567 in. (38.67 to 38.80 mm.).
1.343 to 1.348 in. (34.11 to 34.23 mm.).
.3422 to .3427 in. (8.68 to 8.69 mm.).
.3417 to .3422 in. (8.660 to 8.661 mm.).
.0015 to .0025 in. (.0381 to .0778 mm.).
.002 to .003 in. (.0508 to .0762 mm.).
.3645 in. (9.25 mm.).
MGB. Issue7. 80619

GENERAL DATA—continued
(18G/18GA~co,ntinued)
Valve guides
Length: Inlet ..
Exhaust . ..
Outside diameter: Inlet and exhaust
Inside diameter: Inlet and exhaust
Fitted height above head: Inlet and exhaust ..
Interference fit in head: Inlet and exhaust
(Later cars)
Length: Inlet .. .. .. ..
Fitting height above head: Inlet ..
Valve springs
Free length: Inner ..
Outer
Fitted length: Inner ..
Outer ..
Load at fitted length: Inner
Outer
Load at top of lift: Inner ..
Outer
Valve crash speed
Valve timing
Timing marks .. ..
Rocker clearance: Running
Timing
Inlet valve: Opens
Closes
Exhaust valve: Opens
Closes
ENGINE LUBRICATION
System .. .. ..
System pressure: Running ..
Idling
Oil pump
Capacity
Oil filter .. ..
By-pass valve opens
Oil pressure relief valve .. ..
Relief valve spring: Free length
Fitted length .. ..
Load at ■tted length
FUEL SYSTEM
Carburetters
Choke diameter
Jet size
Needles
Piston spring
Air cleaners
Fuel pump
Type (Early cars) ..
Minimum ■ow
MGB. lssue6. 69615
livin. (41.275 mm.).
2gin. (55.95 mm.).
.5635 to .5640 in. (14.30 to 14.32 mm.).
.3442 to .3447 in. (8.73 to 8.74 mm.).
%in. (15.875 mm.).
.0005 to .00175 in. (.012 to .044 mm.).
1%‘in. (47.63 mm.).
3%:
in. (19 mm.).
1% in. (50.0 mm.).
2&in. (54.4 mm.).
1% in. (36.5 mm.).
11% in. (39.7 mm.).
28 to 321b. (12.7 to 14.5 kg.).
72 lb. (32.7 kg.).
48 to 52 lb. (21.7 to 23.6 kg.).
117 lb. (53 kg.).
6,200 rpm.
Dimples on camshaft and crankshaft wheels.
.015 in. (.38 mm.) cold.
.055 in. (1.4 mm.).
16°B.T.D.C.
56°A.B.D.C.
51°B.B.D.C.
21‘°A.T.D.C.
Wet sump, pressure fed.
’1
Between 50 and 801b./sq. in. (3.51 and 5.6 kg./cm.2).
Between 10 and 25 lb./sq. in. (.7 and 1.7 kg./crn.2).
Hobourn-Eaton 0r eccentric rotor. 7“.
3% gal./min. at 2,000 rpm.
Tecalemit full-■ow felt element.
13 to 17 lb./sq. in. (.9 to 1.1 kg./cm.2).
70 lb./sq. in. (4.9 kg./cm.2).
3 in. (76.2 mm.).
2%in. (54.7 mm.).
15.5 to 16.5 lb. (7.0 to 7.4 kg.).
Twin S.U. type HS4.
11Ain. (38.1 mm.).
.090 in. (2.2 mm.).
No. 5(Standard), No. 6 (Rich), No. 21 (Weak).
Red.
Copper paper element.
S.U. electric HP.
7gal/hr. (31.8 litres/ha, 8.4 US. gal./hr.).
GeneralData 3'

GENERAL DATA—continued
(l8G/180A—continued)
Suction head .. .. .. .. .. .. .. .. 2ft. 6in. (76.2 cm.).
Delivery head. .. .. .. .. .. .. .. .. 4ft. (122 cm.).
Minimum starting voltage .. .. .. .. .. .. 9.5 volts.
Type (Later cars) .. .. .. .. .. .. .. .. S.U. electric AUF 300.
Minimum ■ow .. .. .. .. .. .. .. .. 15 gal/hr. (68.2 litre/hr. 18 US. gal./hr.).
Suction head .. .. .. .. .. .. .. .. 18 in. (457 mm.).
COOLING SYSTEM
Type .I
Pressurized. Pump—impeller—and fan-assisted.
Thermostat setting
Standard .. .. .. .. .. .. .. .. .. 74°C. (165°F.).
Hot climate .. .. .. .. .. .. .. .. 74°C. (165 °F.).
Cold climate .. .. .. .. .. .. .. .. 82°C. (180°F.).
Pressure cap .. .. .. .. .. .. ... .. .. 7lb. (3.175 kg.).
Fan blades .. .. .. .. .. .. .. .. .. 3at 24°.
Fan belt: Width .. .. .. .. .. .. .. .. %in. (9.5 mm.).
Outside length. .. .. .. .. .. .. 351/2in. (90.2 cm.).
Thickness .. .. .. .. .. .. .. 7% in. (7.9 mm.).
Tension .. .. .. .. .. .. .. .. 1/2
in. (12.8 mm.).movement.
Type of pump .. .. .. .. .. .. .. .. .. Centrifugal.
Pump drive .. .. .. .. .. .. .. .. .. Belt from crankshaft pulley.
IGNITION SYSTEM
Coil .. .. .. .. .. .. .. .. .. .. HA.12 (oil-filled).
Resistance at 20°C. (68°F): Primary winding .. .. .. 3.1 to 3.5 ohms (cold).
Consumption: Ignition switch on .. .. .. .. .. 3.9 amps.
At 2,000 r.p.m. .. .. .. .. .. 1.4 amps.
Distributor . .. .. .. 25D4.
Rotation of rotor .. .. .. .. .. .. .. Anti-clockwise.
Cam form .. .. .. .. .. .. .. .. .. 4-cylinder high-lift.
Cam closed period .. .. .. .. .. .. .. 60°i3°.
Cam opened period .. .. .. .. .. .. .. 30 i3 °.
Automatic advance .. .. .. .. .. .. .. Centrifugal and vacuum.
Serial Number Serial Number
.40897 (H.C.) 40916 (L.C.)
Automatic advance commences .. .. .. .. .. 400 r.p.m. 400 r.p.m.
Maximum advance (crankshaft degrees) .. .. .. .. 20° at 200 r.p.m. 24° at,4,400 r.p.m.
Vacuum advance (crankshaft degrees) .. .. .. .. 20° at 13 in. (33.3 cm.) 16° at 12 in. (30.5 cm.).
Hg. Hg.
Decelerating check (crankshaft degrees, engine r.p.m.) .. 20°at 2,200 r.p.m. 24° at 4,400 r.p.m.
15°'at 1,600 r.p.m. 18° at 3,000 r.p.m.
9° at 900 r.p.m. 9° at 1,000 r.p.m.
6° at 700 r.p.m. 8° at 800 r.p.m.
6° at 600 r.p.m. 6° at 600 r.p.m.
Contact point gap setting .. .. .. .. .. .. .014 to .016 in. (.35 to .40 mm.).
Breaker spring tension .. .. .. .. .. .. .. 18 to 24 oz. (510 to 680 gm.)
Condenser capacity .. .. .. .. .. .. .. .18 to .24 mF.
Timing marks .. .. .. .. .. .. .. .. Pointer on timing chain case and notch on crankshaft
pulley.
Static ignition timing: H.C. .. .. .. .. .. .. 10°-B.T.D.C. (98/100-octane fuel).
L.C. .. .. .. .. .. .. 8°B.T.D.C. (95/97-0ctane fuel).
Stroboscopic ignition timing: H.C. .. .. .. .. .. 14° B.T.D.C. at 600 r.p.m. '
L.C. .. .. .. .. .. 12° B.T.D.C. at 600 r.p.m.
Suppressors .. .. .. .. .. .. .. .. .. Lucas W55 Type L.2. Fitted in plug leads.
Sparking plugs .. .. .. .. .. .. .. .. .. Champion N-9Y.
Size .. .. .. .. .. .. .. .. .. .. 14 mm. %in. (19.0 mm.) reach.
Gap .. .. .. .. .. .. .. .. .. .. .024 to .026 in. (.625 to .660 mm.).
MGB. Issue6. 69615

GENERAL DATA—continued
(18G/18GA—continued)
CLUTCH
Make and type
Diaphragm spring colour
Clutch plate diameter
Facing material
Number of damper springs
Damper spring load
Damper spring colour
Clutch release bearing
Clutch fluid
GEARBOX AND OVERDRIVE
Number of forward gears ..
Gearbox ratios: Reverse ..
First
Second ..
Third
Fourth ..
Overdrive ratio ..
Overall gear ratios: Reverse
First ..
Second
Third
Fourth ..
Top gear speed per 1,000 rpm: Standard
Overdrive ..
Standard
Overdrive
Synchromesh hub springs: Free length ..
Fitted length
Load at fitted length
Shaft and reverse plunger detent springs: Free length
Speedometer gear ratio:
Fitted length .. ..
Load at fitted length
Reverse plunger springs: Free length ..
Fitted length
Load at fitted length
Mainshaft second and third gear end-■oat
Laygear end-■oat
Overdrive
Pump spring: Free length
Rate
Clutch spring: Free length
Rate
PROPELLER SHAFT
Type
Universal joints
Angular movement .. .. .. ..
Overall length: Fully extended: Standard
Overdrive
Fully compressed: Standard
Overdrive
Length of shaft assembly: Standard
Overdrive
Tube diameter ..
MGB. Issue9. 25729
Borg &Beck 8 in. DS.G. diaphragm spring.
Dark blue.
8in. (20.32 cm.).
Wound yarn.
6.
110 to 120 lb. (49.8 to 54.3.kg.).
Black/ light green.
Graphite (MY3D).
Lockheed Disc Brake Fluid (Series II).
4.
4.76 :
3.64 :
2.21 :
1.37 2
1.00 :
.802 :1.
18.588 :1.
14.214 :1.
8.656 :1.
5.369 :1. 4.306 :1.
3.909: 1. 3.135 21.
17.9 m.p.h. (27.3 km.p.h.).
22.3 m.p.h. (35.5 km.p.h.).
9/28.
5/16.
1/2
in. (12.7 mm.).
157;
in. (7.9 mm.).
4to 5lb. (1.8 to 2.2 kg.).
11% in. (30.16.mm.).
3%:
in. (19.0 mm.).
18 to 201b. (8.16 to 9.07 kg.).
1 in. (25.4 mm.).
—}%
in. (20.63 mm).
911/2to 921/2lb. (41.4 to 41.9 kg.).
.004 to.006 in. (.10 to .15 mm.).
.002 to .003 in. (.05 to .08 mm.).
h—ah—Ip—ab—Ib—t
Overdrive
2.000 in. (50.8 mm.).
11 lb. in. (12.7 kg.cm.).
1.510 in. (38.3 mm.).
154 lb. in. (178 kg. am).
Open tubular, telescopic.
Hardy Spicer needle roller.
18° to 20 °.
30% in. (78.1 cm.).
31%vin. (81 cm.).
29 1%in. (74 cm.).
30% in. (76.5 cm.).
251% in. (64.3 cm.).
26 ■gin. (67 cm.).
2in. (50.8 mm.).
GeneralData 5

REAR AXLE
Type '
Ratio .. ..’ .. ..
Differential bearing preload
Pinion bearing preload .. ..
Backlash adjustment: Crown wheel ..
Pinion
STEERING
Type .. ..
..
Steering-wheel diameter
Turns—lock to lock ..
Turning circle ..
Universal joint
Pinion end-■oat
Damper end-■oat
Toe-in. . .. .. .. .. ..
Angle of outer wheel with inner wheel at 20°
FRONT SUSPENSION
Type .. .. ..
Spring: Coil diameter (mean)
Free height ..
Static length at 1,030 lb. (467.2 kg.) load ..
Number of free coils
Camber angle ..
Castor angle
King pin inclination ..
Dampers
Arm centres
Wheel bearing end-■oat
REAR SUSPENSION
Type .. .. ..
Number of spring leaves
Width of spring leaves
Gauge of leaves
Early c'ars
Later cars .. ..
Working load (1:15 lb. [7 kg.])
Early cars ..
Later cars
Dampers
Arm centres
ELECTRICAL EQUIPMENT
System .. . ..
Charging system ..
Batteries—two 6-volt
Capacity: '10-hour rate ’
20-hour rate
'Plates per cell .. ..
Electrolyte to ■ll one ce
GeneralData 6
GENERAL DATA—continued
(18G/180chontinued)
Hypoid, three-quarter—■oating.
3.909: 1(11/43).
.002 in. (.05 mm.) ‘nip’ per bearing.
7to 9lb. in. (.8 to 1.0 kg.m.).
Shims.
Head washer.
Rack and pinion.
16% in. (419.10 mm.).
2.93.
32 ft. (9.75 m.).
Hardy Spicer K0518, GB166.
.002 to .005 in. (.05 to .12 mm.).
.0005 to .003 in. (.012 to .076 mm.) (unladen).
1—16‘120
%in. (1.5 to 2.3 mm.) (unladen).
19°&1°:.
Independent. Coil spring and wishbone.
3.238 in. (82.2 mm.).
9.91 1%».11’1.
(251.4i1.5 mm.).
7r ■vin. (178:8 mm.).
7.5.
Nominal 1°.positive (+%°, —114°)
=1% °{positive, 54°negative
Nominal 7°(+%°, —2°)=5° to 734°
Nominal 8°(+1°, —%°)=7%°to 9c
Armstrong piston type.
8in. (203.2 mm.).
,
.002 to .004 in. (.05 to .10 mm.).
(unladen).
Semi-elliptic leaf spring.
5+ bottom plate. Interleaving >1/2, 2/3, 3/4.
1% in. (44.4 mm.).
37?
in. (5.56 mm.).
3at 372
in. (5.6 mm.), 3at %’m. (4.8 mm.).
400 lb. (181.5 kg).
4501b. (204.1 kg).
Armstrong piston type.
5% in. (133 mm.).
12-volt, positive earth.
Current/voltage control
Lucas SG9E or STGZ9E.
Lucas BT9E or BTZ9E—later cars.
51 amp-hr.
58 amp.-hr.
9. ‘
1pint (570 c.c.: 1.2 US. pints).
MGB. Issue9. 25729 i

GENERAL DATA—continued
(18G/l8GA—continued)
Regulator
Voltage setting at 3,000 r.p.m.: 10°C. (50°F.)
20°C. (68°F.)
30°C. (86°F.)
Current setting at 4,000 r.p.m.
Cut-out relay: Cut-in voltage ..
Drop-off voltage
Reverse current ..
Current regulator ..
Dynamo ..
Maximum output ..
Cut-in speed
Field resistance
Brush spring tension
Drive .. ..
Drive adjustment ..
Starter motor ..
Lock torque ..
Torque at 1,000 r.p.m. ..
Brush spring tension
Starter gear ratio ..
Wiper motor .
Drive to wheelboxes
Armature end-float.
Running current ..
Wiping speed
Horns
Type .. .. .. ..
Maximum current consumption
BRAKES
Type ..
Brake ■uid
Front
Disc diameter
Pad material
Swept area ..
Rear
Drum diameter
Lining material
Swept area ..
Lining dimensions
WHEELS
Type
Size: Disc
Wire
MGB. Issue 11‘. 83910
40°C. (104°F.)
RB.340.
14.9 to 15.5 volts.
14.7 to 15.3 volts.
14.5 to 15.1 volts.
14.3 to 14.9 volts.
22 amps.
12.7 to 13.3 volts.
9.5 to 11.0 volts.
3.0 to 5.0 amps.
22i1 amp.
C40/ 1. 12-volt two-brush.
22 amps.
1,585 r.p.m. at 13.0 volts.
6.0 ohms.
22 to 25 oz. (623 to 708 gm.).
Belt from crankshaft.
Swinging link on dynamo.
M418G four-brush inertia type.
15 1b. ft. (2.1 kg. m.) at 425 amps.
8lb. ft. (1.11 kg. m.) at 250 to 270 amps.
32 to 40 oz. (907 to 1133 gm).
13.3 :1. -
DR.3A single speed.
Rack and cable.
.008 to .012 in. (.20 to .30 mm.).
2.7 to 3.4 amps.
45 to 50 cycles per minute.
9H 12-volt.
31/2amps.
Lockheed hydraulic. Disc front, drum rear.
Lockheed Disc Brake Fluid (Series II).
10% in. (27.3 cm.).
Don 55—FF.
203.2 sq. in. (1311 cm.2).
10 in. (25.4 cm.).
Don 24—FE.
106.8 sq. in. (683.9 cm.2).
9%xl%x %in. (240x44.4x4.76 mm.).
Ventilated disc, 4-stud fixing.
Wire (optional).
41x 14.
4%Jx14.
GeneralData?

GENERAL DATA—continued
.47
TYRES
Standard: Size ..
Rolling radius ..
Optional: Size
(18G/18GA—continued)
5.60— 14 (tubed).
11.65 in. (29.5 cm.) at 30 mph. (48 km.p.h.).
155—14.
TYRE PRESSURES
Standard tyres Optional tyres
Condition 560—14 [55—14
Front Rear Front Rear
Normal car weight 18 lb./sq. in. 18 lb./ sq. in. 21 lb./sq. in. 24 lb./sq. in.
(1.3 kg./cm.2) (1.3 kg./cm£2)
.
(1.5 k'g./cm.2) (1.7 kg./cm.'2)
Sustained speeds in excess 24 1b./sq. in. 24 lb./sq. in. 27 lb./sq. in. 31 lb./sq. in.
of 90 mph. (145 km.p.h.) (1.7 kg./cm.2) (1.7 kg./cm.2) (1.9 kg./cm.2) (2.2 kg./cm.2)
NOTE: Rear tyre pressures may be increased by 2lb./sq. in. (.14 kg./cm.2) with advantage when towing with aladen boot.
CAPACITIES
Fuel tank: Early cars
Later cars
Cooling system
Heater
Engine sump
Oil cooler
Gearbox .. ..
Gearbox and overdrive
Rear axle
Steering rack
DIMENSIONS
Overall length .. .. ..
Overall length (with over-riders) ..
Overall width .. .. .. .
Overall height (hood erected)
Ground clearance (minimum)
Wheelbase .. .. ..
Track: Front (disc wheels)
Rear (disc wheels)
Front (wire wheels)
Rear (wire wheels)
-xzz/ ::
WEIGHTS
Unladen weight ..
Engine (dry, with clutch) ..
Gearbox .. .. .
Rear axle: Disc wheels
Wire wheels
10 gallons (45.4 litres, 12 US. gallons).
12 gallons (54 litres, 14 US. gallons).
9% pints (5.4 litres, 11.4 US. pints).
‘■pint (.28 litre, .6 US. pint).
71/; pints (4.26 litres, 9US. pints).
3%:
pint (.42 litre, .9 US. pint).
4% pints (2.56 litres, 5.6 US. pints).
5% pints (3.36 litres, 6 US. pints).
2% pints (1.28 litres, 2.75 US. pints).
§pint (.19 litre, .39 US. pint).
12 ft. 81/2 in. (3.874 m.).
12 ft. 913;,in. (3.897 m.).
4ft. 111% in. (152.3 cm.).
4ft. 13m. (125.4 cm.).
5in. (12.7 cm.).
7ft. 7 in. (231.1 cm.).
4ft. 1 in. (124.4 crn.).
4ft. 1% in. (125 cm.).
4ft. 1% in. (125 cm.).
4ft. 1% in. (125 cm.).
1,920 lb. (871 kg).
358 lb. (163.3 kg.) approx.
78 lb. (35.5 kg.) approx.
117% lb. (53.26 kg.) approx.
123 lb. (55.79 kg.) approx.
MGB. Issuell. 83910

GENERAL DATA—continued
(l8G/l8GA—continued)
TORQUE WRENCH SETTINGS
Engine
MGB.
Main bearing nuts
Flywheel set screws
Gudgeon pin clamp bolt
Big—endbolts
Cylinder head nuts
Rocker bracket nuts
Oil pump to crankcase ..
Sump to crankcase '
Cylinder side cover screws ..
Second type~deep pressed cover
Timing cover—% in. screws
Timing cover— %in. screws
Rear plate— 157;
in. screws
Rear plate—% in. screws ..
Water pump to crankcase
Water outlet elbow nuts
Rocker cover nuts
Manifold nuts
Oil filter centre-bolt
Clutch to ■ywheel
Carburetter stud nuts '.. .. ..
Distributor clamp bolt (nut trapped)
Distributor clamp nut (bolt trapped)
Fan blade ■xing screws ..
Rear axle
Crown wheel to differential carrier ..
Differential bearing cap ..
Pinion beating nut .
Rear brake adjuster securing nuts
Bearing retaining nut
Rear suspension
Rear Shock absorber bolts
Front suspension
Front shock absorber bolts
Brake disc to hub ..
Brake calliper mounting
Bearing retaining nut
Cross-member to body ..
Steering
Steering arm bolts
Steering wheel nut
Steering tie-rod lock nut
Steering lever ball joint nut
Steering universal joint bolt
Road wheels
Road wheel nuts ..
Issue5. 15676
70 lb. ft. (9.7 kg.m.).
40 1b. ft. (5.5 kg.m.).
25 1b. ft. (3.4 kg.m.).
35 to 401b. ft. (4.8 to 5.5 kg.m.).
45 to 501b. ft. (6.2 to 6.9 kg.m.).
25 lb. ft. (3.4 kg.m.).
141b. ft. (1.9 kg.m.).
61b. ft. (.8 kg. m.).
2lb. ft. (.28 kg. m.).
5lb. ft. (.7 kg. m.).
6lb. ft. (.8 kg. m.).
14 lb. ft. (1.9 kg. m.).
20 lb. ft. (2.8 kg. m.).
30 lb. ft. (4.1 kg. m.).
17 1b. ft. (2.4 kg. m.).
8lb. ft. (1.1 kg. m.).
4lb. ft. (.56 kg. m.).
15 1b. ft. (2.1 kg. m.).
151b. ft. (2.1 kg. m.). _
25 to 30 lb. ft. (3.4 to 4.1 kg. m.).
2lb. ft. (.28 kg. m.).
4.16 lb. ft. (.57 kg. m.).
2.5 lb. ft. (.35 kg. m.).
7.3 to 9.3 lb. ft. (1 to 1.3 kg. m.).
55 to 601b. ft. (7.6 to 8.3 kg. m.).
60 to 65 lb. ft. (8.3 to 8.9 kg. m.).
135 to 140 1b. ft. (18.6 to 19.3 kg. m.).
5to 71b. ft. (.69 to .97 kg. m.).
1801b. ft. (24.8 kg. m.).
55 to 60 lb. ft. (7.6 to 8.3 kg. m.).
\
43 to 45 lb. ft. (5.9 to 6.2 kg. m.).
40 to 45 lb. ft. (5.5 to 6.2 kg. m.).
40 to 45 lb. ft. (5.5 to 6.2 kg. m.).
40 to 70 lb. ft. (5.5 to 9.7 kg. m.).
54 to 56 lb. ft. (7.5 to 7.7 kg. m.).
60 to 65 1b. ft. (8.3 to 8.9 kg. m.).
41 to 43 1b. ft. (5.7 to 5.9 kg. m.).
33.3 to 37.5 lb. ft. (4.6 to 5.2 kg. m.).
34 to 35 1b. ft. (4.7 to 4.8 kg. m.). vV
20 to 22 lb. ft. (2.8 to 3.0 kg. m.).
60 to 65 1b. ft. (8.3 to 9kg. m.).
GeneralData 9

GENERAL DATA
(18GB)
The following information is applicable to the lSGB-engined cars and should be used in conjunction with the preceding
specification for the 18G/ISGA-engined car.
ENGINE
Type
Main bearings
Number and type .. .. ..
Length: Front, centre and rear
Intermediate
Connecting rods
Type ..
Big-end bearings
Length
Pistons
Gudgeon pin bore .. ..
Clearance in cylinder skirt: To
Bottom ..
Gudgeon pin
Type ..
Fit in piston
Diameter (outer) ..
FUEL SYSTEM
Carburetter needles ..
REAR AXLE (GT)
Type
Ratio .. .. .. .. .. ..
Differential bearing preload .. .. .. ..
Pinion bearing preload. New collapsible spacer only
Pinion bearing preload. Oil seal change spacer collapsed ..
Backlash adjustment:
Crown wheel ..
Pinion
FRONT SUSPENSION (GT)
Spring coil diameter (mean)
Free height
Number of free coils .. .. .. .. .. ..
Static length at load of 1,193 lb. (541.5 kg.)i201b. (9.1 kg.)
REAR SUSPENSION (GT)
Spring detail
Working load (i15 lb. 7kg.) ..
WHEELS (GT)
Size ;Disc
MGB. Issue6. 8%‘19
12;. 4..
18GB.
5thin-wall.
1%in. (28.5 mm.).
%in. (22.23 mm.).
Angular-split big-end, bushed small-end.
.775 to .785 in. (19.68 to 19.94 mm.).
.8126 to .8129 (20.610 to 20.167 mm.).
.0012 to .0006 in. (.030 to .015 mm.).
.0033 to .0021 in. (.080 to .050 mm.).
Fully ■oating.
.0001 to .00035 in. (.0025 to .007 mm.).
.8124 to .8127 (20.608 to 20.615 mm.).
FX (Standard); No. 6 (Rich);No. 21 (Weak).
Hypoid, semi-■oating.
3.909 2l(11.43).
.002 in. (.05 mm.) nip per bearing.
14 to 18 lb. in. (.161 to .207 kg. m.).
Adjust to preload, refer Section Ha.4.
Shims.
Head washer.
3.28 in. (83.3 mm.).
9.1:t1—16in.
(231i1.6 mm.).
7.2.
6.6 in. (168 mm.).
51010(32L6kg)
5] x14in.
GeneralData 11

GENERAL DATA—continued
(18GB—continued)
TYRES (GT)
Optional:
Size and type—Early cars
I_ater cars
Standard tyres:
Pressures (set cold):
Front
Rear ..
Sustained speeds in excess of 90 m.p.h. (145 km.p.h.):
Front
Rear ..
Optional tyres:
Pressures (set cold):
Front
Rear ..
Sustained speeds in excess of 90 m.p.h. (145 km.p.h.):
Front .. .. .. .. ..
Rear ..
CAPACITIES ‘
Rear axle (semi-■oating type)
DIMENSIONS
Overall height (GT) ..
WEIGHTS
Unladen weight (GT)
TORQUE WRENCH SETTINGS
Rear Axle
Half-shaft nut (semi-floating axle)
Differential bearing cap bolts ..
Crown wheel bolts .
Pinion nut, new spacer only
Pinion nut, oil sea] change
Axle shaft nut
\GeneralData 12
165—14 SP4].
165—14 SP68.
20 lb./sq. in. (1.4 kg./cm.2).
24 1b./sq. in. (1.7 kg./cm.2).
26 lb./sq. in. (1.8 kg./cm.2).
301b./sq. in. (2.1 kg./cm.2).
21 lb./sq. in. (1.5 kg./cm.2).
24 lb./sq. in. (1.7 kg./cm.2).
28 lb./sq. in. (2.0 kg./cm.2).
31 lb./sq. in. (2.2 kg./cm.2).
1% pints (.85 litre, 2US. pints).
4ft. 1% in. (126.3 cm.).
2,1901b. (993 kg.).
150 lb. ft. (20.75 kg. m.).
50 to 551b. ft. (6.9 to 7.6 kg. m.).
60' to 65 lb. ft. (8.3 to 8.9 kg. m.).
180 to 220 lb. ft. (28.89 to 30.42 kg. m.).
Adjust to preload. See Section Ha.
'150 1b. ft. (20.6 kg. m.) and aligned to next split pin
hole.
MGB. Issue6. 80619

GENERAL DATA
(GHN4/GHD4 CARS, 18GD ENGINE—GHNS/GH‘DS CARS, 18GG ENGINE)
The following information is applicable to the GHN4 and GHD4 series cars ■tted with 18GB engines and Gl-lNS/GHDS
cars fitted with 18GG engines and should be used in conjunction with the preceding speci■cations. ‘
ENGINE
Type
Pistons
Type .. .. .. .. ..
Clearance of skirt in cylinder: Top ..
Bottom
Number of rings .. .. .. ..
Width of ring grooves: Compression
Oil control ..
Piston rings
Type: Compression: Top ..
Second ..
Oil control
Fitted gap: Compression
Oil control ..
Width: Compression
Oil control ..
Thickness: Compression: Top
Second
Gudgeon pin
Type ..
Diameter
Fit in: Piston ..
Small end ..
Connecting rods
Type .. .. .. ..
Length between centres
Locking method big-end
COOLING SYSTEM
Fan belt: Width
Length
Thickness ..
Tension
Thermostat:
Normal
Hot climates
Cold climates
FUEL SYSTEM
Carburetter needles ..
MGB. Issue3. 80619
18GD—18GG.
Aluminium solid skirt, three rings.
.0021 to .0033 in. (.053 to .084 mm.).
.006 to .0012 in. (.015 to .030 mm.).
Three; 2 compression. 1oil control.
.064 to- .065 in. (1.625 to 1.651 mm.).
.1578 to .1588 in. (4.01 to 4.033 mm.).
Plain, sintered alloy.
Tapered, sintered alloy—marked ‘TOP’.
Two chrome-faced rings with expander, Apex.
.012 to .022 in. (.305 to .600 mm.). '
.015 to .045 in. (.38 to 1.14 mm.).
.0615 to .0625 in. (1.56 to 1.59 mm.).
.152 to .158 in. (3.86 to 4.01 mm.).
.124 to .127 in. (3.14 to 3.22 mm.).
.104 to .111 in. (2.64 to 2.81 mm.).
Press ■tin connecting rod.
.8125 to .8127 in. (20.63 to 20.64 mm.).
Hand push fit at 16°C. (60°F.).
12 lb. ft.(1.7 kg. m.) minimum using ISO 1150 and
adaptor type C.
Horizontal split big-end, solid small-end.
6.5 in. (165.1 mm.).
Multi-sided nut.
km. (11.9 mm.).
35% in. (90.2 cm.) at gin. width equivalent.
■in. (10.7 mm.).
1A in. (12.8 mm.) movement at midway of longest
run.
82° c. (180° F.).
74° 0. (165° F.).
88° C. (190° F.).
FX (Standard), No. 6 (Rich), GZ (Weak).
GeneralData 13
1