General Data

Specifications from the official MGB Workshop Manual.

Engine

18G / 18GA Engine — General

Type 18G, 18GA
Number of cylinders 4
Bore 3.16 in. (80.26 mm)
Stroke 3.5 in. (89 mm)
Capacity 1798 c.c. (109.8 cu. in.)
Combustion chamber volume (valves fitted) 42.5 to 43.5 c.c. (2.59 to 2.65 cu. in.)
Firing order 1, 3, 4, 2
Valve operation Overhead by push-rod
Compression ratio — H.C. 8.8 : 1
Compression ratio — L.C. 8.0 : 1
Compression pressure — H.C. 160 lb./sq. in. (11.25 kg./cm.²)
Compression pressure — L.C. 130 lb./sq. in. (9.15 kg./cm.²)
Torque — H.C. 110 lb. ft. (15.2 kg.m.) at 3,000 r.p.m.
Torque — L.C. 105 lb. ft. (14.5 kg.m.) at 3,000 r.p.m.
Engine idle speed (approx.) 500 r.p.m.
Oversize bore — First .010 in. (.254 mm)
Oversize bore — Maximum .040 in. (1.016 mm)

18GB Engine — General

The following applies to 18GB-engined cars; use in conjunction with the 18G/18GA specifications above.

Type 18GB

18GD / 18GG Engine — General (GHN4/GHD4 and GHN5/GHD5)

The following applies to GHN4/GHD4 cars with 18GD engines and GHN5/GHD5 cars with 18GG engines; use in conjunction with the preceding specifications.

Type 18GD (GHN4/GHD4), 18GG (GHN5/GHD5)

18V Engine — General (GHN5/GHD5 from Car No. 258001)

Type — Synchromesh gearbox 18V 581F – 18V 581Y – 18V 779F – 18V 846F
Type — Synchromesh gearbox with overdrive 18V 582F – 18V 582Y – 18V 780F – 18V 847F
Type — Automatic transmission 18V 583F – 18V 583Y

Emission Control Engine Types (GHN4/GHD4 and GHN5/GHD5)

EEC = Exhaust Emission Control; ELC = Evaporative Loss Control. Service and tuning must follow Workshop Manual Supplement AKO 4957.

Type (1967–69) 18GF (EEC)
Type (1969–70) 18GH (EEC, carburetter crankcase ventilation)
Type (1969–70) 18GJ (EEC, ELC, carburetter crankcase ventilation)
Type (1970–71) 18GK (EEC, ELC)
Type (1971–72) 18V 5842 (EEC, ELC — non-overdrive)
Type (1971–72) 18V 5852 (EEC, ELC — overdrive)
Type (1972–74) 18V 6722 (EEC, ELC — non-overdrive)
Type (1972–74) 18V 6732 (EEC, ELC — overdrive)

Crankshaft

18G / 18GA

Main journal diameter 2.1262 to 2.127 in. (54.01 to 54.02 mm)
Crankpin journal diameter 1.8759 to 1.8764 in. (47.648 to 47.661 mm)
Crankshaft end-thrust Taken on thrust washers at centre main bearing
Crankshaft end-float .004 to .005 in. (.10 to .13 mm)

Main Bearings

18G / 18GA

Number and type Three thin-wall
Material Steel-backed copper-lead
Length 1¼ in. (28.5 mm)
Diametrical clearance .001 to .0027 in. (.0254 to .068 mm)
Undersizes −.010, −.020, −.030 and −.040 in. (−.254, −.508, −.762 and −1.016 mm)

18GB

Number and type Five thin-wall
Length — front, centre and rear 1½ in. (28.5 mm)
Length — intermediate ⅞ in. (22.23 mm)

Connecting Rods

18G / 18GA

Type Angular-split big-end, split clamp small-end
Length between centres 6.5 in. (165.1 mm)

18GB

Type Angular-split big-end, bushed small-end

18GD / 18GG

Type Horizontal-split big-end, solid small-end
Length between centres 6.5 in. (165.1 mm)
Locking method — big-end Multi-sided nut

Big-End Bearings

18G / 18GA

Type Shell
Material Steel-backed copper-lead
Length .995 to 1.005 in. (25.2 to 25.52 mm)
Diametrical clearance .001 to .0027 in. (.0254 to .068 mm)
Undersizes −.010, −.020, −.030 and −.040 in. (−.254, −.508, −.762 and −1.016 mm)
End-float on crankpin (nominal) .008 to .012 in. (.20 to .30 mm)

18GB

Length .775 to .785 in. (19.68 to 19.94 mm)

Pistons

18G / 18GA

Type Aluminium solid skirt
Clearance in cylinder — top .0036 to .0045 in. (.091 to .121 mm)
Clearance in cylinder — bottom .0018 to .0024 in. (.045 to .060 mm)
Number of rings 4 (3 compression, 1 oil control)
Width of ring grooves — top, second, third .064 to .065 in. (1.625 to 1.651 mm)
Width of ring grooves — oil control .1578 to .1588 in. (4.008 to 4.033 mm)
Gudgeon pin bore .7501 to .7503 in. (19.052 to 19.057 mm)

18GB

Gudgeon pin bore .8126 to .8129 in. (20.610 to 20.167 mm)
Clearance in cylinder skirt — top .0006 to .0012 in. (.015 to .030 mm)
Clearance in cylinder skirt — bottom .0021 to .0033 in. (.050 to .080 mm)

18GD / 18GG

Type Aluminium solid skirt, three rings
Clearance of skirt in cylinder — top .0021 to .0033 in. (.053 to .084 mm)
Clearance of skirt in cylinder — bottom .0006 to .0012 in. (.015 to .030 mm)
Number of rings Three: 2 compression, 1 oil control
Width of ring grooves — compression .064 to .065 in. (1.625 to 1.651 mm)
Width of ring grooves — oil control .1578 to .1588 in. (4.010 to 4.033 mm)

Piston Rings

18G / 18GA — Compression Rings

Type — top Parallel, cast non-molybdenum filled
Type — second and third Tapered, cast non-molybdenum filled
Width — top, second and third .0615 to .0625 in. (1.562 to 1.587 mm)
Fitted gap — top, second and third .012 to .017 in. (.304 to .431 mm)
Ring to groove clearance — top, second and third .0015 to .0035 in. (.038 to .088 mm)

18G / 18GA — Oil Control Ring

Type Slotted scraper
Width .1552 to .1562 in. (3.94 to 3.96 mm)
Fitted gap .012 to .017 in. (.304 to .431 mm)
Ring to groove clearance .0016 to .0036 in. (.04 to .09 mm)

18GD / 18GG — Compression Rings

Type — top Plain, sintered alloy
Type — second Tapered, sintered alloy — marked ‘TOP’
Fitted gap .012 to .022 in. (.305 to .600 mm)
Width .0615 to .0625 in. (1.56 to 1.59 mm)
Thickness — top .124 to .127 in. (3.14 to 3.22 mm)
Thickness — second .104 to .111 in. (2.64 to 2.81 mm)

18GD / 18GG — Oil Control Ring

Type Two chrome-faced rings with Apex expander
Fitted gap .015 to .045 in. (.38 to 1.14 mm)
Width .152 to .158 in. (3.86 to 4.01 mm)

Gudgeon Pin

18G / 18GA

Type Semi-floating
Fit in piston Free fit at 20°C. (68°F.)
Diameter (outer) .7499 to .7501 in. (19.04 to 19.05 mm)

18GB

Type Fully floating
Fit in piston .0001 to .00035 in. (.0025 to .007 mm)
Diameter (outer) .8124 to .8127 in. (20.608 to 20.615 mm)

18GD / 18GG

Type Press fit in connecting rod
Diameter .8125 to .8127 in. (20.63 to 20.64 mm)
Fit in piston Hand push fit at 16°C. (60°F.)
Fit in small-end 12 lb. ft. (1.7 kg.m.) minimum using tool 18G 1150 with adaptor type C

Camshaft

18G / 18GA

Journal diameter — front 1.78875 to 1.78925 in. (45.424 to 45.437 mm)
Journal diameter — centre 1.72875 to 1.72925 in. (43.910 to 43.923 mm)
Journal diameter — rear 1.62275 to 1.62325 in. (41.218 to 41.230 mm)
Bearing inside diameter (reamed after fitting) — front 1.79025 to 1.79075 in. (45.472 to 45.485 mm)
Bearing inside diameter (reamed after fitting) — centre 1.73025 to 1.73075 in. (43.948 to 43.961 mm)
Bearing inside diameter (reamed after fitting) — rear 1.62425 to 1.62475 in. (41.256 to 41.269 mm)
Diametrical clearance .001 to .002 in. (.0254 to .0508 mm)
End-thrust Taken on locating plate
End-float .003 to .007 in. (.076 to .178 mm)
Cam lift .250 in. (6.35 mm)
Drive Chain and sprocket from crankshaft
Timing chain ⅜ in. (9.52 mm) pitch × 52 pitches

Tappets

18G / 18GA

Type Barrel with flat base
Outside diameter ⅓in. (20.64 mm)
Length 2.293 to 2.303 in. (58.25 to 58.5 mm)

Rocker Gear

18G / 18GA — Rocker Shaft

Length 14⅛ in. (356 mm)
Diameter .624 to .625 in. (15.85 to 15.87 mm)

18G / 18GA — Rocker Arm

Bore .7485 to .7495 in. (19.01 to 19.26 mm)
Rocker arm bush inside diameter .6255 to .626 in. (15.8 to 15.9 mm)
Ratio 1.4 : 1

Valves

18G / 18GA

Seat angle — inlet and exhaust 45½°
Head diameter — inlet 1.562 to 1.567 in. (38.67 to 38.80 mm)
Head diameter — exhaust 1.343 to 1.348 in. (34.11 to 34.23 mm)
Stem diameter — inlet .3422 to .3427 in. (8.68 to 8.69 mm)
Stem diameter — exhaust .3417 to .3422 in. (8.660 to 8.661 mm)
Stem to guide clearance — inlet .0015 to .0025 in. (.0381 to .0778 mm)
Stem to guide clearance — exhaust .002 to .003 in. (.0508 to .0762 mm)
Valve lift — inlet and exhaust .3645 in. (9.25 mm)

18V Engine — Early Cars (Inlet Valve)

Seat angle 45½°
Head diameter 1.625 to 1.630 in. (41.27 to 41.40 mm)
Stem diameter 0.3429 to 0.3434 in. (8.70 to 8.72 mm)
Stem to guide clearance 0.0008 to 0.0018 in. (0.020 to 0.046 mm)

18V Engine — Later Cars

Head diameter — inlet 1.562 to 1.567 in. (39.67 to 39.80 mm)
Head diameter — exhaust 1.343 to 1.348 in. (34.11 to 34.23 mm)
Stem diameter — inlet 0.3429 to 0.3434 in. (8.70 to 8.72 mm)
Stem diameter — exhaust 0.3423 to 0.3428 in. (8.69 to 8.70 mm)
Stem to guide clearance — inlet 0.0007 to 0.0019 in. (0.020 to 0.045 mm)
Stem to guide clearance — exhaust 0.0013 to 0.0025 in. (0.03 to 0.06 mm)

Valve Guides

18G / 18GA

Length — inlet 1⅝ in. (41.275 mm)
Length — exhaust 2¼ in. (55.95 mm)
Outside diameter — inlet and exhaust .5635 to .5640 in. (14.30 to 14.32 mm)
Inside diameter — inlet and exhaust .3442 to .3447 in. (8.73 to 8.74 mm)
Fitted height above head — inlet and exhaust ⅝ in. (15.875 mm)
Interference fit in head — inlet and exhaust .0005 to .00175 in. (.012 to .044 mm)
Length — inlet (later cars) 1¾ in. (47.63 mm)
Fitting height above head — inlet (later cars) ¾ in. (19 mm)

Valve Springs

18G / 18GA (Inner and Outer Springs)

Free length — inner 1⅞ in. (50.0 mm)
Free length — outer 2⅛ in. (54.4 mm)
Fitted length — inner 1&frac716; in. (36.5 mm)
Fitted length — outer 1&frac916; in. (39.7 mm)
Load at fitted length — inner 28 to 32 lb. (12.7 to 14.5 kg.)
Load at fitted length — outer 72 lb. (32.7 kg.)
Load at top of lift — inner 48 to 52 lb. (21.7 to 23.6 kg.)
Load at top of lift — outer 117 lb. (53 kg.)
Valve crash speed 6,200 r.p.m.

18V Engine (Single Spring)

Free length 1.92 in. (48.77 mm)
Fitted length 1.44 in. (36.58 mm)
Load at fitted length 82 lb. (37.2 kg.)
Load at top of lift 142 lb. (64.4 kg.)

Valve Timing

18G / 18GA

Timing marks Dimples on camshaft and crankshaft wheels
Rocker clearance — running .015 in. (.38 mm) cold
Rocker clearance — timing .055 in. (1.4 mm)
Inlet valve opens 16° B.T.D.C.
Inlet valve closes 56° A.B.D.C.
Exhaust valve opens 51° B.B.D.C.
Exhaust valve closes 21° A.T.D.C.

Engine Lubrication

18G / 18GA

System Wet sump, pressure fed
System pressure — running 50 to 80 lb./sq. in. (3.51 to 5.6 kg./cm.²)
System pressure — idling 10 to 25 lb./sq. in. (.7 to 1.7 kg./cm.²)
Oil pump type Hobourn-Eaton or eccentric rotor
Oil pump capacity 3¼ gal./min. at 2,000 r.p.m.
Oil filter Tecalemit full-flow felt element
By-pass valve opens 13 to 17 lb./sq. in. (.9 to 1.1 kg./cm.²)
Oil pressure relief valve 70 lb./sq. in. (4.9 kg./cm.²)
Relief valve spring — free length 3 in. (76.2 mm)
Relief valve spring — fitted length 2&frac316; in. (54.7 mm)
Relief valve spring — load at fitted length 15.5 to 16.5 lb. (7.0 to 7.4 kg.)

Fuel System

18G / 18GA

Carburetters Twin S.U. type HS4
Choke diameter 1½ in. (38.1 mm)
Jet size .090 in. (2.2 mm)
Needles No. 5 (Standard), No. 6 (Rich), No. 21 (Weak)
Piston spring Red
Air cleaners Copper paper element
Fuel pump type (early cars) S.U. electric HP
Minimum flow (early pump) 7 gal./hr. (31.8 litres/hr., 8.4 U.S. gal./hr.)
Suction head (early pump) 2 ft. 6 in. (76.2 cm)
Delivery head (early pump) 4 ft. (122 cm)
Minimum starting voltage (early pump) 9.5 volts
Fuel pump type (later cars) S.U. electric AUF 300
Minimum flow (later pump) 15 gal./hr. (68.2 litres/hr., 18 U.S. gal./hr.)
Suction head (later pump) 18 in. (457 mm)

18GB

Carburetter needles FX (Standard), No. 6 (Rich), No. 21 (Weak)

18GD / 18GG

Carburetter needles FX (Standard), No. 6 (Rich), GZ (Weak)

Emission Control Engine Types — Carburetter Needles

18GF FX
18GH – 18GJ AAE
18GK AAL
18V 5842 and 18V 5852 AAU
18V 6722 and 18V 6732 ABO

Fuel Tank Capacity (18GJ and 18GK engines)

Fuel tank capacity 12 U.S. gallons (45.4 litres)

Cooling System

18G / 18GA

Type Pressurized, pump-impeller and fan-assisted
Thermostat setting — standard 74°C. (165°F.)
Thermostat setting — hot climate 74°C. (165°F.)
Thermostat setting — cold climate 82°C. (180°F.)
Pressure cap 7 lb. (3.175 kg.)
Fan blades 3 at 24°
Fan belt — width ½ in. (9.5 mm)
Fan belt — outside length 35½ in. (90.2 cm)
Fan belt — thickness ¼ in. (7.9 mm) (approx.)
Fan belt — tension ½ in. (12.8 mm) movement
Pump type Centrifugal
Pump drive Belt from crankshaft pulley

18GD / 18GG

Fan belt — width 15/32 in. (11.9 mm)
Fan belt — length 35½ in. (90.2 cm) at ⅜ in. width equivalent
Fan belt — thickness 27/64 in. (10.7 mm)
Fan belt — tension ½ in. (12.8 mm) movement at midway of longest run
Thermostat — normal 82°C. (180°F.)
Thermostat — hot climates 74°C. (165°F.)
Thermostat — cold climates 88°C. (190°F.)

Ignition System

18G / 18GA

Coil HA.12 (oil-filled)
Coil primary resistance at 20°C. (68°F.) 3.1 to 3.5 ohms (cold)
Coil consumption — ignition switch on 3.9 amps
Coil consumption 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° ± 3°
Cam opened period 30° ± 3°
Automatic advance Centrifugal and vacuum
Automatic advance commences (H.C. – Serial No. 40897; L.C. – Serial No. 40916) 400 r.p.m. (both)
Maximum advance — H.C. (crankshaft degrees) 20° at 2,000 r.p.m.
Maximum advance — L.C. (crankshaft degrees) 24° at 4,400 r.p.m.
Vacuum advance — H.C. 20° at 13 in. (33.3 cm) Hg
Vacuum advance — L.C. 16° at 12 in. (30.5 cm) Hg
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)
Static ignition timing — L.C. 8° B.T.D.C. (95/97-octane fuel)
Stroboscopic ignition timing — H.C. 14° B.T.D.C. at 600 r.p.m.
Stroboscopic ignition timing — 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
Plug size 14 mm, ¾ in. (19.0 mm) reach
Plug gap .024 to .026 in. (.625 to .660 mm)

Emission Control Engine Types — Distributor Serial Numbers

Make/type Lucas 25D4
18GF Serial No. 40897
18GH – 18GJ Serial No. 41155
18GK Serial No. 41339
18V 5842 and 18V 5852 Serial No. 41370
18V 6722 and 18V 6732 Serial No. 41491

Clutch

18G / 18GA

Make and type Borg & Beck 8 in. D.S.G. diaphragm spring
Diaphragm spring colour Dark blue
Clutch plate diameter 8 in. (20.32 cm)
Facing material Wound yarn
Number of damper springs 6
Damper spring load 110 to 120 lb. (49.8 to 54.3 kg.)
Damper spring colour Black/light green
Clutch release bearing Graphite (MY3D)
Clutch fluid Lockheed Disc Brake Fluid (Series II)

18GD / 18GG

Clutch fluid Lockheed Disc Brake Fluid (Series 329)

Gearbox and Overdrive

18G / 18GA

Number of forward gears 4
Gearbox ratio — reverse 4.76 : 1
Gearbox ratio — first 3.64 : 1
Gearbox ratio — second 2.21 : 1
Gearbox ratio — third 1.37 : 1
Gearbox ratio — fourth 1.00 : 1
Overdrive ratio .802 : 1
Overall ratio — reverse 18.588 : 1
Overall ratio — first 14.214 : 1
Overall ratio — second 8.656 : 1
Overall ratio — third 5.369 : 1 (overdrive: 4.306 : 1)
Overall ratio — fourth 3.909 : 1 (overdrive: 3.135 : 1)
Top gear speed per 1,000 r.p.m. — standard 17.9 m.p.h. (27.3 km.p.h.)
Top gear speed per 1,000 r.p.m. — overdrive 22.3 m.p.h. (35.5 km.p.h.)
Speedometer gear ratio — standard 9/28
Speedometer gear ratio — overdrive 5/16
Synchromesh hub springs — free length ½ in. (12.7 mm)
Synchromesh hub springs — fitted length 5/16 in. (7.9 mm)
Synchromesh hub springs — load at fitted length 4 to 5 lb. (1.8 to 2.2 kg.)
Shaft and reverse plunger detent springs — free length 1¼ in. (30.16 mm)
Shaft and reverse plunger detent springs — fitted length ¾ in. (19.0 mm)
Shaft and reverse plunger detent springs — load at fitted length 18 to 20 lb. (8.16 to 9.07 kg.)
Reverse plunger springs — free length 1 in. (25.4 mm)
Reverse plunger springs — fitted length 13/16 in. (20.63 mm)
Reverse plunger springs — load at fitted length 91½ to 92½ lb. (41.4 to 41.9 kg.)
Mainshaft second and third gear end-float .004 to .006 in. (.10 to .15 mm)
Laygear end-float .002 to .003 in. (.05 to .08 mm)
Overdrive pump spring — free length 2.000 in. (50.8 mm)
Overdrive pump spring — rate 11 lb. in. (12.7 kg.cm.)
Overdrive clutch spring — free length 1.510 in. (38.3 mm)
Overdrive clutch spring — rate 154 lb. in. (178 kg.cm.)

18GD / 18GG (Synchromesh Gearbox)

Number of forward gears 4
Synchromesh All forward gears
Gearbox ratio — reverse 3.095 : 1
Gearbox ratio — first 3.44 : 1
Gearbox ratio — second 2.167 : 1
Gearbox ratio — third 1.382 : 1
Gearbox ratio — fourth 1.000 : 1
Overdrive type Laycock L.H.
Overdrive ratio .82 : 1
Overall ratio — reverse 12.098 : 1
Overall ratio — first 13.45 : 1
Overall ratio — second 8.47 : 1
Overall ratio — third 5.4 : 1 (overdrive: 4.43 : 1)
Overall ratio — fourth 3.909 : 1 (overdrive: 3.2 : 1)
Top gear speed per 1,000 r.p.m. — standard 18 m.p.h. (29 km.p.h.)
Top gear speed per 1,000 r.p.m. — overdrive 22 m.p.h. (35 km.p.h.)
Speedometer gear ratio — standard 10 : 26
Speedometer gear ratio — overdrive 8 : 21
Synchromesh hub springs — free length .72 in. (18.3 mm)
Synchromesh hub springs — fitted length .385 in. (9.8 mm)
Synchromesh hub springs — load at fitted length 5.5 to 6 lb. (2.5 to 2.7 kg.)
First and third speed gear end-float .005 to .008 in. (.13 to .20 mm)
Second gear end-float .005 to .008 in. (.13 to .20 mm)
Laygear end-float .002 to .003 in. (.05 to .08 mm)

18GD / 18GG (Automatic Gearbox)

Torque converter ratio 2.2 : 1 to 1 : 1
Gearbox ratio — reverse 2.09 : 1
Gearbox ratio — first 2.39 : 1
Gearbox ratio — second 1.45 : 1
Gearbox ratio — top 1.00 : 1
Overall ratio (converter at 1:1) — reverse 8.17 : 1
Overall ratio (converter at 1:1) — first 9.34 : 1
Overall ratio (converter at 1:1) — second 5.668 : 1
Overall ratio (converter at 1:1) — top 3.909 : 1
Speedometer gear ratio 10 : 26

Propeller Shaft

18G / 18GA

Type Open tubular, telescopic
Universal joints Hardy Spicer needle roller
Angular movement 18° to 20°
Overall length fully extended — standard 30¾ in. (78.1 cm)
Overall length fully extended — overdrive 31¼ in. (81 cm)
Overall length fully compressed — standard 29¼ in. (74 cm)
Overall length fully compressed — overdrive 30¼ in. (76.5 cm)
Length of shaft assembly — standard 25½ in. (64.3 cm)
Length of shaft assembly — overdrive 26&frac316; in. (67 cm)
Tube diameter 2 in. (50.8 mm)

Rear Axle

18G / 18GA (Three-Quarter-Floating)

Type Hypoid, three-quarter-floating
Ratio 3.909 : 1 (11/43)
Differential bearing preload .002 in. (.05 mm) nip per bearing
Pinion bearing preload 7 to 9 lb. in. (.8 to 1.0 kg.m.)
Backlash adjustment — crown wheel Shims
Backlash adjustment — pinion Head washer

18GB — GT (Semi-Floating)

Type Hypoid, semi-floating
Ratio 3.909 : 1 (11/43)
Differential bearing preload .002 in. (.05 mm) nip per bearing
Pinion bearing preload — new collapsible spacer only 14 to 18 lb. in. (.161 to .207 kg.m.)
Pinion bearing preload — oil seal change, spacer collapsed Adjust to preload — refer Section Ha.4
Backlash adjustment — crown wheel Shims
Backlash adjustment — pinion Head washer

18GD / 18GG (Semi-Floating)

Type Hypoid, semi-floating
Ratio 3.909 : 1 (11/43)
Differential bearing preload .002 in. (.05 mm) nip per bearing
Pinion bearing preload Refer to Section Ha.4
Backlash adjustment — crown wheel Shims
Backlash adjustment — pinion Head washer

Steering

18G / 18GA

Type Rack and pinion
Steering-wheel diameter 16½ in. (419.10 mm)
Turns lock to lock 2.93
Turning circle 32 ft. (9.75 m)
Universal joint Hardy Spicer KO518, GB 166
Pinion end-float .002 to .005 in. (.05 to .12 mm)
Damper end-float (unladen) .0005 to .003 in. (.012 to .076 mm)
Toe-in (unladen) 1/16 to 3/32 in. (1.5 to 2.3 mm)
Angle of outer wheel with inner wheel at 20° 19° ± 1°

Front Suspension

18G / 18GA (Tourer)

Type Independent, coil spring and wishbone
Spring coil diameter (mean) 3.238 in. (82.2 mm)
Spring free height 9.9 ± 1/16 in. (251.4 ± 1.5 mm)
Static length at 1,030 lb. (467.2 kg.) load 7 ± 1/32 in. (178 ± .8 mm)
Number of free coils 7.5
Camber angle Nominal 1° positive (+¼°, −1¼°) = ¾° to 1¼° positive (unladen)
Castor angle Nominal 7° (+¼°, −2°) = 5° to 7¼° (unladen)
King pin inclination Nominal 8° (+1°, −¾°) = 7¼° to 9°
Dampers Armstrong piston type
Damper arm centres 8 in. (203.2 mm)
Wheel bearing end-float .002 to .004 in. (.05 to .10 mm)

18GB (GT)

Spring coil diameter (mean) 3.28 in. (83.3 mm)
Spring free height 9.1 ± 1/16 in. (231 ± 1.6 mm)
Number of free coils 7.2
Static length at load of 1,193 lb. (541.5 kg.) ± 20 lb. (9.1 kg.) 6.6 in. (168 mm)

18V Engine — Tourer from Car No. 293446

Free height 10.20 ± 0.06 in. (259.08 ± 1.5 mm)
Static length at load of 1,030 ± 20 lb. (467 ± 9 kg.) 7.24 in. (187.70 mm)
No. of free coils 7.5

18V Engine — Tourer, Later Cars

Free height (nominal) 10.20 in. (259.08 mm)
Static length at load of 1,030 ± 20 lb. (467 ± 9 kg.) 7.44 in. (188.98 mm)
No. of free coils 9

18V Engine — GT from Car No. 296196

Free height 9.32 ± ¼ in. (236.73 ± 1.6 mm)
Static length at load of 1,193 ± 20 lb. (541 ± 9 kg.) 6.84 in. (173.74 mm)
No. of free coils 7.2

Rear Suspension

18G / 18GA (Tourer)

Type Semi-elliptic leaf spring
Number of spring leaves 5 + bottom plate; interleaving 1/2, 2/3, 3/4
Width of spring leaves 1¾ in. (44.4 mm)
Gauge of leaves — early cars 7/32 in. (5.56 mm)
Gauge of leaves — later cars 3 at 7/32 in. (5.6 mm), 3 at 3/16 in. (4.8 mm)
Working load (±15 lb. [7 kg.]) — early cars 400 lb. (181.5 kg.)
Working load (±15 lb. [7 kg.]) — later cars 450 lb. (204.1 kg.)
Dampers Armstrong piston type
Damper arm centres 5¼ in. (133 mm)

18GB (GT)

Working load (±15 lb. [7 kg.]) 510 lb. (231.6 kg.)

18V Engine

Number of spring leaves 6, interleaving between 1/2, 2/3
Width of spring leaves 1.76 in. (44.7 mm)
Gauge of leaves — 1st, 2nd, 3rd 0.2187 ± 0.006 in. (5.55 ± 0.152 mm)
Gauge of leaves — 4th, 5th, 6th 0.1875 ± 0.006 in. (4.75 ± 0.152 mm)
Working load 510 to 540 lbf. (231 to 245 kgf.)

Electrical Equipment

18G / 18GA — System

System voltage and earth 12-volt, positive earth
Charging system Current/voltage control

18G / 18GA — Batteries (Two 6-Volt)

Type (early cars) Lucas SG9E or STGZ9E
Type (later cars) Lucas BT9E or BTZ9E
Capacity — 10-hour rate 51 amp.-hr.
Capacity — 20-hour rate 58 amp.-hr.
Plates per cell 9
Electrolyte to fill one cell 1 pint (570 c.c., 1.2 U.S. pints)

18G / 18GA — Regulator (RB.340)

Voltage setting at 3,000 r.p.m. at 10°C. (50°F.) 14.9 to 15.5 volts
Voltage setting at 3,000 r.p.m. at 20°C. (68°F.) 14.7 to 15.3 volts
Voltage setting at 3,000 r.p.m. at 30°C. (86°F.) 14.5 to 15.1 volts
Voltage setting at 3,000 r.p.m. at 40°C. (104°F.) 14.3 to 14.9 volts
Current setting at 4,000 r.p.m. 22 amps
Cut-out relay — cut-in voltage 12.7 to 13.3 volts
Cut-out relay — drop-off voltage 9.5 to 11.0 volts
Reverse current 3.0 to 5.0 amps
Current regulator 22 ± 1 amp

18G / 18GA — Dynamo (C40/1)

Type C40/1, 12-volt two-brush
Maximum output 22 amps
Cut-in speed 1,585 r.p.m. at 13.0 volts
Field resistance 6.0 ohms
Brush spring tension 22 to 25 oz. (623 to 708 gm.)
Drive Belt from crankshaft
Drive adjustment Swinging link on dynamo

18G / 18GA — Starter Motor (M418G Inertia Type)

Type M418G four-brush inertia type
Lock torque 15 lb. ft. (2.1 kg.m.) at 425 amps
Torque at 1,000 r.p.m. 8 lb. ft. (1.11 kg.m.) at 250 to 270 amps
Brush spring tension 32 to 40 oz. (907 to 1,133 gm.)
Starter gear ratio 13.3 : 1

18G / 18GA — Wiper Motor (DR.3A)

Type DR.3A single speed
Drive to wheelboxes Rack and cable
Armature end-float .008 to .012 in. (.20 to .30 mm)
Running current 2.7 to 3.4 amps
Wiping speed 45 to 50 cycles per minute

18G / 18GA — Horns

Type 9H 12-volt
Maximum current consumption 3½ amps

18GD / 18GG — System

System voltage and earth 12-volt, negative earth

18GD / 18GG — Batteries (Two 6-Volt)

Type (early cars) Lucas BT9E or BTZ9E
Type (later cars) Lucas CA9E
Capacity — 10-hour rate (early) 51 amp.-hour
Capacity — 10-hour rate (later) 53 amp.-hour
Capacity — 20-hour rate (early) 58 amp.-hour
Capacity — 20-hour rate (later) 60 amp.-hour
Plates per cell 9
Electrolyte to fill one cell 1 pint (570 c.c., 1.2 U.S. pints)

18GD / 18GG — Control Box (4TR Electronic)

Type 4TR Electronic
Voltage setting 14.3 to 14.7 volts at 5,000 r.p.m.

18GD Engine — Alternator (Lucas 16AC)

Type Lucas 16AC
Output at 14 volts and 6,000 r.p.m. 34 amps
Maximum permissible rotor speed 12,500 r.p.m.
Pulley ratio — alternator/crankshaft 1.795 : 1
Stator phases 3
Rotor poles 12
Rotor winding resistance 4.33 ohms ± 5% at 20°C. (68°F.)
Brush length (new) ½ in. (12.6 mm)
Brush spring tension 7 to 10 oz. (198 to 283 gm.) with brush face flush with brush box

18GG Engine — Alternator (Lucas 16ACR)

Type Lucas 16ACR
Output and specifications Data as 16AC (above)

18GD / 18GG — Starter Motor (Lucas M418G Pre-Engaged)

Type Lucas M418G Pre-engaged
Light running current 70 amp. at 5,800 to 6,500 r.p.m.
Lock torque 17 lb. ft. (2.35 kg.m.) at 465 amps
Torque at 1,000 r.p.m. 7 lb. ft. (.97 kg.m.) at 260 amps
Solenoid closing coil resistance .13 to .15 ohm
Solenoid hold-on coil resistance .63 to .73 ohm
Brush spring tension 36 oz. (1.02 kg.)

18GD / 18GG — Starter Motor Relay (Lucas 6RA)

Type Lucas Model 6RA – 33243
Winding resistance 76 ohms
Air gap (contacts open) .030 ± .005 in. (.76 ± .13 mm)
Air gap (contacts closed) .010 ± .003 in. (.25 ± .08 mm)
Cut-in voltage 4.0 to 7.5 volts
Drop-off voltage 5 volts (maximum)

18GD / 18GG — Wiper Motor (Lucas 14W Two-Speed)

Type Lucas 14W (two-speed)
Armature end-float .004 to .008 in. (.10 to .21 mm)
Light running current — normal speed 1.5 amp
Light running current — high speed 2.0 amp
Light running speed — normal 46 to 52 r.p.m.
Light running speed — high 60 to 70 r.p.m.

18V Engine — Starter Motor (Lucas 2M 100)

Type Lucas 2M 100 Pre-engaged
Brush spring tension 36 oz. (1.02 kg.)
Minimum brush length ⅜ in. (9.5 mm)
Minimum commutator thickness 0.140 in. (3.5 mm)
Lock torque 14.4 lb. ft. (2.02 kg.m.) with 463 amps
Torque at 1,000 r.p.m. 7.3 lb. ft. (1.02 kg.m.) with 300 amps
Light running current 40 amp. at 6,000 r.p.m. (approx.)
Maximum armature end-float 0.010 in. (0.25 mm)
Solenoid closing (series) winding resistance 0.25 to 0.27 ohm
Solenoid hold-on (shunt) winding resistance 0.76 to 0.80 ohm

Brakes

18G / 18GA

Type Lockheed hydraulic — disc front, drum rear
Brake fluid Lockheed Disc Brake Fluid (Series II)
Front disc diameter 10¾ in. (27.3 cm)
Front pad material Don 55-FF
Front swept area 203.2 sq. in. (1,311 cm.²)
Rear drum diameter 10 in. (25.4 cm)
Rear lining material Don 24-FE
Rear swept area 106.8 sq. in. (683.9 cm.²)
Rear lining dimensions 9&frac1116; × 1¾ × 3/16 in. (240 × 44.4 × 4.76 mm)

18GD / 18GG

Brake fluid Lockheed Disc Brake Fluid (Series 329)

Wheels

18G / 18GA (Tourer)

Type Ventilated disc, 4-stud fixing; wire (optional)
Size — disc 4J × 14
Size — wire 4½J × 14

18GB (GT)

Size — disc 5J × 14 in.

18GD / 18GG

Pressed disc — Tourer 4½ × 14
Pressed disc — GT 5½ × 14
Pressed spoked 5½ F/H × 14
Wire (optional) 4½J × 14 (60-spoke)

Tyres

18G / 18GA (Tourer)

Standard size 5.60-14 (tubed)
Rolling radius (standard, at 30 m.p.h.) 11.65 in. (29.5 cm)
Optional size 155-14

18GB (GT)

Optional size — early cars 165-14 SP41
Optional size — later cars 165-14 SP68

Tyre Pressures

18G / 18GA (Tourer)

Standard 5.60-14 — normal weight, front 18 lb./sq. in. (1.3 kg./cm.²)
Standard 5.60-14 — normal weight, rear 18 lb./sq. in. (1.3 kg./cm.²)
Standard 5.60-14 — sustained speeds over 90 m.p.h., front 24 lb./sq. in. (1.7 kg./cm.²)
Standard 5.60-14 — sustained speeds over 90 m.p.h., rear 24 lb./sq. in. (1.7 kg./cm.²)
Optional 155-14 — normal weight, front 21 lb./sq. in. (1.5 kg./cm.²)
Optional 155-14 — normal weight, rear 24 lb./sq. in. (1.7 kg./cm.²)
Optional 155-14 — sustained speeds over 90 m.p.h., front 27 lb./sq. in. (1.9 kg./cm.²)
Optional 155-14 — sustained speeds over 90 m.p.h., rear 31 lb./sq. in. (2.2 kg./cm.²)

Rear tyre pressures may be increased by 2 lb./sq. in. (.14 kg./cm.²) when towing with a laden boot.

18GB (GT) — Standard Tyres (set cold)

Normal weight, front 20 lb./sq. in. (1.4 kg./cm.²)
Normal weight, rear 24 lb./sq. in. (1.7 kg./cm.²)
Sustained speeds over 90 m.p.h., front 26 lb./sq. in. (1.8 kg./cm.²)
Sustained speeds over 90 m.p.h., rear 30 lb./sq. in. (2.1 kg./cm.²)

18GB (GT) — Optional Tyres (set cold)

Normal weight, front 21 lb./sq. in. (1.5 kg./cm.²)
Normal weight, rear 24 lb./sq. in. (1.7 kg./cm.²)
Sustained speeds over 90 m.p.h., front 28 lb./sq. in. (2.0 kg./cm.²)
Sustained speeds over 90 m.p.h., rear 31 lb./sq. in. (2.2 kg./cm.²)

18GD / 18GG (Tourer) — 5.60-14S Cross-Ply

Normal car weight, front 19 lb./sq. in. (1.34 kg./cm.²)
Normal car weight, rear 22 lb./sq. in. (1.55 kg./cm.²)
Maximum weight, front 19 lb./sq. in. (1.34 kg./cm.²)
Maximum weight, rear 24 lb./sq. in. (1.69 kg./cm.²)

18GD / 18GG (Tourer) — 155SR-14 Radial-Ply

Normal car weight, front 21 lb./sq. in. (1.48 kg./cm.²)
Normal car weight, rear 24 lb./sq. in. (1.69 kg./cm.²)
Maximum weight, front 21 lb./sq. in. (1.48 kg./cm.²)
Maximum weight, rear 26 lb./sq. in. (1.83 kg./cm.²)

18GD / 18GG (GT)

Normal car weight, front 20 lb./sq. in. (1.4 kg./cm.²)
Normal car weight, rear 24 lb./sq. in. (1.69 kg./cm.²)
Maximum weight, front 20 lb./sq. in. (1.4 kg./cm.²)
Maximum weight, rear 26 lb./sq. in. (1.83 kg./cm.²)
Tyre size (GT) 165SR-14 (pressures as Tourer above)

For sustained speeds at or near maximum, increase the above tyre pressures by 6 lb./sq. in. (.42 kg./cm.²).


Capacities

18G / 18GA

Fuel tank — early cars 10 gallons (45.4 litres, 12 U.S. gallons)
Fuel tank — later cars 12 gallons (54 litres, 14 U.S. gallons)
Cooling system 9½ pints (5.4 litres, 11.4 U.S. pints)
Heater ½ pint (.28 litre, .6 U.S. pint)
Engine sump 7½ pints (4.26 litres, 9 U.S. pints)
Oil cooler ¾ pint (.42 litre, .9 U.S. pint)
Gearbox 4½ pints (2.56 litres, 5.6 U.S. pints)
Gearbox and overdrive 6 pints (3.36 litres, 6 U.S. pints)
Rear axle 2¼ pints (1.28 litres, 2.75 U.S. pints)
Steering rack ½ pint (.19 litre, .39 U.S. pint)

18GB — Additional

Rear axle (semi-floating type) 1¼ pints (.85 litre, 2 U.S. pints)

18GD / 18GG

Gearbox 5¼ pints (3 litres, 6 U.S. pints)
Gearbox and overdrive 6 pints (3.4 litres, 7 U.S. pints)
Automatic gearbox 10½ pints (6 litres, 12.7 U.S. pints)
Rear axle 1½ pints (.85 litres, 2 U.S. pints)

18V Engine — GHN5/GHD5 from Car No. 410002

Fuel tank 12 gallons (54.5 litres, 14.4 U.S. gallons)
Cooling system 11½ pints (6.6 litres, 13.8 U.S. pints)
Cooling system with heater 12 pints (6.8 litres, 14.4 U.S. pints)

Dimensions

18G / 18GA

Overall length 12 ft. 8½ in. (3.874 m)
Overall length (with over-riders) 12 ft. 9¼ in. (3.897 m)
Overall width 4 ft. 11&frac516; in. (152.3 cm)
Overall height (hood erected) 4 ft. 1⅜ in. (125.4 cm)
Ground clearance (minimum) 5 in. (12.7 cm)
Wheelbase 7 ft. 7 in. (231.1 cm)
Track — front (disc wheels) 4 ft. 1 in. (124.4 cm)
Track — rear (disc wheels) 4 ft. 1¼ in. (125 cm)
Track — front (wire wheels) 4 ft. 1¼ in. (125 cm)
Track — rear (wire wheels) 4 ft. 1¼ in. (125 cm)

18GB (GT)

Overall height (GT) 4 ft. 1¾ in. (126.3 cm)

18V Engine — GHN5/GHD5 from Car No. 410002

Track — front 4 ft. 1½ in. (124.7 cm)
Track — rear 4 ft. 1¾ in. (126.4 cm)

Weights

18G / 18GA

Unladen weight 1,920 lb. (871 kg.)
Engine (dry, with clutch) 358 lb. (163.3 kg.) approx.
Gearbox 78 lb. (35.5 kg.) approx.
Rear axle — disc wheels 117½ lb. (53.26 kg.) approx.
Rear axle — wire wheels 123 lb. (55.79 kg.) approx.

18GB (GT)

Unladen weight (GT) 2,190 lb. (993 kg.)

18GD / 18GG

Kerbside weight — Tourer 2,303 lb. (1,044 kg.)
Kerbside weight — GT 2,401 lb. (1,088 kg.)
Normal weight (kerbside + driver, passenger, 50 lb. luggage) — Tourer 2,653 lb. (1,203 kg.)
Normal weight — GT 2,751 lb. (1,248 kg.)
Maximum weight (normal + towbar hitch load) — Tourer 2,753 lb. (1,249 kg.)
Maximum weight — GT 2,851 lb. (1,293 kg.)
Maximum permissible towing weight — Tourer and GT 1,680 lb. (762 kg.)
Maximum towbar hitch load — Tourer and GT 100 lb. (45 kg.)

18V Engine (GHN5/GHD5)

Kerbside weight — Tourer 2,394 lb. (1,088 kg.)
Kerbside weight — GT 2,446 lb. (1,110 kg.)
Normal weight (kerbside + driver and passenger) — Tourer 2,694 lb. (1,223 kg.)
Normal weight — GT 2,746 lb. (1,245 kg.)
Gross weight — Tourer 2,814 lb. (1,277 kg.)
Gross weight — GT 2,866 lb. (1,301 kg.)
Maximum permissible towing weight — Tourer and GT 1,680 lb. (762 kg.)
Maximum towbar hitch load — Tourer and GT 100 lb. (45 kg.)
Maximum roof rack load (GT) 50 lb. (23 kg.)

Torque Wrench Settings

18G / 18GA — Engine

Main bearing nuts 70 lb. ft. (9.7 kg.m.)
Flywheel set screws 40 lb. ft. (5.5 kg.m.)
Gudgeon pin clamp bolt 25 lb. ft. (3.4 kg.m.)
Big-end bolts 35 to 40 lb. ft. (4.8 to 5.5 kg.m.)
Cylinder head nuts 45 to 50 lb. ft. (6.2 to 6.9 kg.m.)
Rocker bracket nuts 25 lb. ft. (3.4 kg.m.)
Oil pump to crankcase 14 lb. ft. (1.9 kg.m.)
Sump to crankcase 6 lb. ft. (.8 kg.m.)
Cylinder side cover screws 2 lb. ft. (.28 kg.m.)
Cylinder side cover screws (second type, deep pressed cover) 5 lb. ft. (.7 kg.m.)
Timing cover — ¼ in. screws 6 lb. ft. (.8 kg.m.)
Timing cover — 5/16 in. screws 14 lb. ft. (1.9 kg.m.)
Rear plate — 5/16 in. screws 20 lb. ft. (2.8 kg.m.)
Rear plate — ⅜ in. screws 30 lb. ft. (4.1 kg.m.)
Water pump to crankcase 17 lb. ft. (2.4 kg.m.)
Water outlet elbow nuts 8 lb. ft. (1.1 kg.m.)
Rocker cover nuts 4 lb. ft. (.56 kg.m.)
Manifold nuts 15 lb. ft. (2.1 kg.m.)
Oil filter centre-bolt 15 lb. ft. (2.1 kg.m.)
Clutch to flywheel 25 to 30 lb. ft. (3.4 to 4.1 kg.m.)
Carburetter stud nuts 2 lb. ft. (.28 kg.m.)
Distributor clamp bolt (nut trapped) 4.16 lb. ft. (.57 kg.m.)
Distributor clamp nut (bolt trapped) 2.5 lb. ft. (.35 kg.m.)
Fan blade fixing screws 7.3 to 9.3 lb. ft. (1.0 to 1.3 kg.m.)

18G / 18GA — Rear Axle

Crown wheel to differential carrier 55 to 60 lb. ft. (7.6 to 8.3 kg.m.)
Differential bearing cap 60 to 65 lb. ft. (8.3 to 8.9 kg.m.)
Pinion bearing nut 135 to 140 lb. ft. (18.6 to 19.3 kg.m.)
Rear brake adjuster securing nuts 5 to 7 lb. ft. (.69 to .97 kg.m.)
Bearing retaining nut 180 lb. ft. (24.8 kg.m.)

18G / 18GA — Rear Suspension

Rear shock absorber bolts 55 to 60 lb. ft. (7.6 to 8.3 kg.m.)

18G / 18GA — Front Suspension

Front shock absorber bolts 43 to 45 lb. ft. (5.9 to 6.2 kg.m.)
Brake disc to hub 40 to 45 lb. ft. (5.5 to 6.2 kg.m.)
Brake calliper mounting 40 to 45 lb. ft. (5.5 to 6.2 kg.m.)
Bearing retaining nut 40 to 70 lb. ft. (5.5 to 9.7 kg.m.)
Cross-member to body 54 to 56 lb. ft. (7.5 to 7.7 kg.m.)

18G / 18GA — Steering

Steering arm bolts 60 to 65 lb. ft. (8.3 to 8.9 kg.m.)
Steering wheel nut 41 to 43 lb. ft. (5.7 to 5.9 kg.m.)
Steering tie-rod lock nut 33.3 to 37.5 lb. ft. (4.6 to 5.2 kg.m.)
Steering lever ball joint nut 34 to 35 lb. ft. (4.7 to 4.8 kg.m.)
Steering universal joint bolt 20 to 22 lb. ft. (2.8 to 3.0 kg.m.)

18G / 18GA — Road Wheels

Road wheel nuts 60 to 65 lb. ft. (8.3 to 9.0 kg.m.)

18GB — Rear Axle

Half-shaft nut (semi-floating axle) 150 lb. ft. (20.75 kg.m.)
Differential bearing cap bolts 50 to 55 lb. ft. (6.9 to 7.6 kg.m.)
Crown wheel bolts 60 to 65 lb. ft. (8.3 to 8.9 kg.m.)
Pinion nut — new spacer only 180 to 220 lb. ft. (28.89 to 30.42 kg.m.)
Pinion nut — oil seal change Adjust to preload — see Section Ha
Axle shaft nut 150 lb. ft. (20.6 kg.m.) aligned to next split pin hole

18GD / 18GG — Automatic Gearbox

Converter to drive plate bolts 25 to 30 lb. ft. (3.46 to 4.15 kg.m.)
Transmission case to converter housing bolts 8 to 13 lb. ft. (1.1 to 1.8 kg.m.)
Extension housing to transmission case bolts 8 to 13 lb. ft. (1.1 to 1.8 kg.m.)
Oil pan to gearbox bolts 8 to 13 lb. ft. (1.1 to 1.8 kg.m.)
Front servo bolts 8 to 13 lb. ft. (1.1 to 1.8 kg.m.)
Rear servo bolts 13 to 27 lb. ft. (1.8 to 3.73 kg.m.)
Pump adaptor to housing screw 2 to 3 lb. ft. (.28 to .41 kg.m.)
Pump adaptor to housing bolts 17 to 32 lb. ft. (2.35 to 4.43 kg.m.)
Pump adaptor to transmission case bolts 8 to 18.5 lb. ft. (1.1 to 2.55 kg.m.)
Manual shaft locknut 7 to 9 lb. ft. (.97 to 1.24 kg.m.)
Pressure adaptor plug 4 to 5 lb. ft. (.55 to .69 kg.m.)
Drain plug 8 to 10 lb. ft. (1.1 to 1.38 kg.m.)
Upper valve body to lower valve body screws 20 to 30 lb. in. (.23 to .345 kg.m.)
Lower valve body to upper valve body screws 20 to 30 lb. in. (.23 to .345 kg.m.)
Oil tube and end plate to valve body screws 20 to 30 lb. in. (.23 to .345 kg.m.)
Valve bodies to transmission case bolts 4.5 to 9 lb. ft. (.61 to 1.24 kg.m.)
Cam bracket screws 20 to 40 lb. in. (.23 to .46 kg.m.)
Governor to counter-weight screws 4 to 5 lb. ft. (.55 to .69 kg.m.)
Governor cover-plate screws 20 to 48 lb. in. (.23 to .552 kg.m.)
Front servo adjusting screw locknut 15 to 20 lb. ft. (2.07 to 2.77 kg.m.)
Rear servo adjusting screw locknut 25 to 30 lb. ft. (3.46 to 4.15 kg.m.)
Starter inhibitor switch locknut 4 to 6 lb. ft. (.55 to .83 kg.m.)
Downshift cable adaptor bolts 8 to 9 lb. ft. (1.1 to 1.24 kg.m.)
Filler tube connector sleeve to transmission case 20 to 30 lb. ft. (2.76 to 4.15 kg.m.)
Filler tube to connector sleeve nut 17 to 18 lb. ft. (2.35 to 2.49 kg.m.)
Stone-guard screws 17 to 19 lb. in. (.196 to .219 kg.m.)
Driving flange nut 55 to 60 lb. ft. (7.6 to 8.3 kg.m.)
Centre support bolts 10 to 18 lb. ft. (1.38 to 2.49 kg.m.)

18GD / 18GG — General

Stiffnut to cross-member mounting bolt 44 to 46 lb. ft. (6.08 to 6.36 kg.m.)
Gearbox remote control cover to tunnel 7.5 to 9.5 lb. ft. (1.04 to 1.31 kg.m.)
Hydraulic brake pipe connection — 3/8 in. UNF 5 to 7 lb. ft. (.69 to .96 kg.m.)
Hydraulic brake pipe connection — ¼ in. UNF 7 to 10 lb. ft. (.96 to 1.38 kg.m.)
Steering-wheel nut — ¼ in. UNF 27 to 29 lb. ft. (3.73 to 4.01 kg.m.)
Steering-wheel nut — 5/8 in. UNF 41 to 43 lb. ft. (5.66 to 5.94 kg.m.)

18GD / 18GG — Electrical

Alternator shaft nut 25 to 30 lb. ft. (3.46 to 4.15 kg.m.)

GHN5/GHD5 — Emission Control Cars — General

Interior mirror special screw 5 lb. in. (.058 kg.m.)
Steering-column top fixing bolts 12 to 17 lb. ft. (1.66 to 2.35 kg.m.)
Steering-column universal joint bolts 20 to 22 lb. ft. (2.8 to 3.04 kg.m.)
Steering-wheel nut 36 to 38 lb. ft. (4.98 to 5.26 kg.m.)
Steering-wheel nut — ¼ in. UNF 27 to 29 lb. ft. (3.73 to 4.00 kg.m.)
Master cylinder port adaptors 33 lb. ft. (4.56 kg.m.)
Master cylinder reservoir fixing bolts 5 lb. ft. (.69 kg.m.)
Brake pressure failure switch (nylon) 15 lb. in. (.173 kg.m.)
Brake pressure failure switch assembly end plug 200 lb. in. (2.3 kg.m.)
Hydraulic brake pipe connection — 3/8 in. UNF 5 to 7 lb. ft. (.69 to .96 kg.m.)
Hydraulic brake pipe connection — 5/16 in. UNF 7 to 10 lb. ft. (.96 to 1.38 kg.m.)

18V Engine — Engine

Big-end nuts (12-sided) 33 lbf. ft. (4.5 kgf.m.)
Crankshaft pulley nut 70 lbf. ft. (9.6 kgf.m.)
Camshaft nut 65 lbf. ft. (8.9 kgf.m.)
Carburetter stud nuts 15 lbf. ft. (2.1 kgf.m.)
Spark plugs 18 lbf. ft. (2.5 kgf.m.)
Oil pipe banjo 37 lbf. ft. maximum (5.1 kgf.m.)
Oil release valve dome nut 43 lbf. ft. (5.9 kgf.m.)
Front plate — 3/8 in. screws 20 lbf. ft. (2.8 kgf.m.)
Rear plate — ¼ in. screws 30 lbf. ft. (4.1 kgf.m.)
Rear engine mounting bolt 38 lbf. ft. (5.22 kgf.m.)

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Specifications from the official MGB Workshop Manual.

Engine

18G / 18GA Engine — General

Type 18G, 18GA
Number of cylinders 4
Bore 3.16 in. (80.26 mm)
Stroke 3.5 in. (89 mm)
Capacity 1798 c.c. (109.8 cu. in.)
Combustion chamber volume (valves fitted) 42.5 to 43.5 c.c. (2.59 to 2.65 cu. in.)
Firing order 1, 3, 4, 2
Valve operation Overhead by push-rod
Compression ratio — H.C. 8.8 : 1
Compression ratio — L.C. 8.0 : 1
Compression pressure — H.C. 160 lb./sq. in. (11.25 kg./cm.²)
Compression pressure — L.C. 130 lb./sq. in. (9.15 kg./cm.²)
Torque — H.C. 110 lb. ft. (15.2 kg.m.) at 3,000 r.p.m.
Torque — L.C. 105 lb. ft. (14.5 kg.m.) at 3,000 r.p.m.
Engine idle speed (approx.) 500 r.p.m.
Oversize bore — first .010 in. (.254 mm)
Oversize bore — maximum .040 in. (1.016 mm)

18GB Engine — General

The following applies to 18GB-engined cars; use in conjunction with the 18G/18GA specifications above.

Type 18GB

18GD / 18GG Engine — General (GHN4/GHD4 and GHN5/GHD5)

The following applies to GHN4/GHD4 cars with 18GD engines and GHN5/GHD5 cars with 18GG engines; use in conjunction with the preceding specifications.

Type 18GD (GHN4/GHD4), 18GG (GHN5/GHD5)

18V Engine — General (GHN5/GHD5 from Car No. 258001)

Type — synchromesh gearbox 18V 581F – 18V 581Y – 18V 779F – 18V 846F
Type — synchromesh gearbox with overdrive 18V 582F – 18V 582Y – 18V 780F – 18V 847F
Type — automatic transmission 18V 583F – 18V 583Y

Emission Control Engine Types (GHN4/GHD4 and GHN5/GHD5)

EEC = Exhaust Emission Control; ELC = Evaporative Loss Control. Service and tuning must follow Workshop Manual Supplement AKO 4957.

Type (1967–69) 18GF (EEC)
Type (1969–70) 18GH (EEC, carburetter crankcase ventilation)
Type (1969–70) 18GJ (EEC, ELC, carburetter crankcase ventilation)
Type (1970–71) 18GK (EEC, ELC)
Type (1971–72) 18V 5842 (EEC, ELC — non-overdrive)
Type (1971–72) 18V 5852 (EEC, ELC — overdrive)
Type (1972–74) 18V 6722 (EEC, ELC — non-overdrive)
Type (1972–74) 18V 6732 (EEC, ELC — overdrive)

Crankshaft

18G / 18GA

Main journal diameter 2.1262 to 2.127 in. (54.01 to 54.02 mm)
Crankpin journal diameter 1.8759 to 1.8764 in. (47.648 to 47.661 mm)
Crankshaft end-thrust Taken on thrust washers at centre main bearing
Crankshaft end-float .004 to .005 in. (.10 to .13 mm)

Main Bearings

18G / 18GA

Number and type Three thin-wall
Material Steel-backed copper-lead
Length 1¼ in. (28.5 mm)
Diametrical clearance .001 to .0027 in. (.0254 to .068 mm)
Undersizes −.010, −.020, −.030 and −.040 in. (−.254, −.508, −.762 and −1.016 mm)

18GB

Number and type Five thin-wall
Length — front, centre and rear 1½ in. (28.5 mm)
Length — intermediate 7/8 in. (22.23 mm)

Connecting Rods

18G / 18GA

Type Angular-split big-end, split clamp small-end
Length between centres 6.5 in. (165.1 mm)

18GB

Type Angular-split big-end, bushed small-end

18GD / 18GG

Type Horizontal-split big-end, solid small-end
Length between centres 6.5 in. (165.1 mm)
Locking method — big-end Multi-sided nut

Big-End Bearings

18G / 18GA

Type Shell
Material Steel-backed copper-lead
Length .995 to 1.005 in. (25.2 to 25.52 mm)
Diametrical clearance .001 to .0027 in. (.0254 to .068 mm)
Undersizes −.010, −.020, −.030 and −.040 in. (−.254, −.508, −.762 and −1.016 mm)
End-float on crankpin (nominal) .008 to .012 in. (.20 to .30 mm)

18GB

Length .775 to .785 in. (19.68 to 19.94 mm)

Pistons

18G / 18GA

Type Aluminium solid skirt
Clearance in cylinder — top .0036 to .0045 in. (.091 to .121 mm)
Clearance in cylinder — bottom .0018 to .0024 in. (.045 to .060 mm)
Number of rings 4 (3 compression, 1 oil control)
Width of ring grooves — top, second, third .064 to .065 in. (1.625 to 1.651 mm)
Width of ring grooves — oil control .1578 to .1588 in. (4.008 to 4.033 mm)
Gudgeon pin bore .7501 to .7503 in. (19.052 to 19.057 mm)

18GB

Gudgeon pin bore .8126 to .8129 in. (20.610 to 20.167 mm)
Clearance in cylinder skirt — top .0006 to .0012 in. (.015 to .030 mm)
Clearance in cylinder skirt — bottom .0021 to .0033 in. (.050 to .080 mm)

18GD / 18GG

Type Aluminium solid skirt, three rings
Clearance of skirt in cylinder — top .0021 to .0033 in. (.053 to .084 mm)
Clearance of skirt in cylinder — bottom .0006 to .0012 in. (.015 to .030 mm)
Number of rings Three: 2 compression, 1 oil control
Width of ring grooves — compression .064 to .065 in. (1.625 to 1.651 mm)
Width of ring grooves — oil control .1578 to .1588 in. (4.010 to 4.033 mm)

Piston Rings

18G / 18GA — Compression Rings

Type — top Parallel, cast non-molybdenum filled
Type — second and third Tapered, cast non-molybdenum filled
Width — top, second and third .0615 to .0625 in. (1.562 to 1.587 mm)
Fitted gap — top, second and third .012 to .017 in. (.304 to .431 mm)
Ring to groove clearance — top, second and third .0015 to .0035 in. (.038 to .088 mm)

18G / 18GA — Oil Control Ring

Type Slotted scraper
Width .1552 to .1562 in. (3.94 to 3.96 mm)
Fitted gap .012 to .017 in. (.304 to .431 mm)
Ring to groove clearance .0016 to .0036 in. (.04 to .09 mm)

18GD / 18GG — Compression Rings

Type — top Plain, sintered alloy
Type — second Tapered, sintered alloy — marked ‘TOP’
Fitted gap .012 to .022 in. (.305 to .600 mm)
Width .0615 to .0625 in. (1.56 to 1.59 mm)
Thickness — top .124 to .127 in. (3.14 to 3.22 mm)
Thickness — second .104 to .111 in. (2.64 to 2.81 mm)

18GD / 18GG — Oil Control Ring

Type Two chrome-faced rings with Apex expander
Fitted gap .015 to .045 in. (.38 to 1.14 mm)
Width .152 to .158 in. (3.86 to 4.01 mm)

Gudgeon Pin

18G / 18GA

Type Semi-floating
Fit in piston Free fit at 20°C. (68°F.)
Diameter (outer) .7499 to .7501 in. (19.04 to 19.05 mm)

18GB

Type Fully floating
Fit in piston .0001 to .00035 in. (.0025 to .007 mm)
Diameter (outer) .8124 to .8127 in. (20.608 to 20.615 mm)

18GD / 18GG

Type Press fit in connecting rod
Diameter .8125 to .8127 in. (20.63 to 20.64 mm)
Fit in piston Hand push fit at 16°C. (60°F.)
Fit in small-end 12 lb. ft. (1.7 kg.m.) minimum using tool 18G 1150 with adaptor type C

Camshaft

18G / 18GA

Journal diameter — front 1.78875 to 1.78925 in. (45.424 to 45.437 mm)
Journal diameter — centre 1.72875 to 1.72925 in. (43.910 to 43.923 mm)
Journal diameter — rear 1.62275 to 1.62325 in. (41.218 to 41.230 mm)
Bearing inside diameter (reamed after fitting) — front 1.79025 to 1.79075 in. (45.472 to 45.485 mm)
Bearing inside diameter (reamed after fitting) — centre 1.73025 to 1.73075 in. (43.948 to 43.961 mm)
Bearing inside diameter (reamed after fitting) — rear 1.62425 to 1.62475 in. (41.256 to 41.269 mm)
Diametrical clearance .001 to .002 in. (.0254 to .0508 mm)
End-thrust Taken on locating plate
End-float .003 to .007 in. (.076 to .178 mm)
Cam lift .250 in. (6.35 mm)
Drive Chain and sprocket from crankshaft
Timing chain 3/8 in. (9.52 mm) pitch × 52 pitches

Tappets

18G / 18GA

Type Barrel with flat base
Outside diameter 13/16 in. (20.64 mm)
Length 2.293 to 2.303 in. (58.25 to 58.5 mm)

Rocker Gear

18G / 18GA — Rocker Shaft

Length 14&frac18; in. (356 mm)
Diameter .624 to .625 in. (15.85 to 15.87 mm)

18G / 18GA — Rocker Arm

Bore .7485 to .7495 in. (19.01 to 19.26 mm)
Rocker arm bush inside diameter .6255 to .626 in. (15.8 to 15.9 mm)
Ratio 1.4 : 1

Valves

18G / 18GA

Seat angle — inlet and exhaust 45½°
Head diameter — inlet 1.562 to 1.567 in. (38.67 to 38.80 mm)
Head diameter — exhaust 1.343 to 1.348 in. (34.11 to 34.23 mm)
Stem diameter — inlet .3422 to .3427 in. (8.68 to 8.69 mm)
Stem diameter — exhaust .3417 to .3422 in. (8.660 to 8.661 mm)
Stem to guide clearance — inlet .0015 to .0025 in. (.0381 to .0778 mm)
Stem to guide clearance — exhaust .002 to .003 in. (.0508 to .0762 mm)
Valve lift — inlet and exhaust .3645 in. (9.25 mm)

18V Engine — Early Cars (Inlet Valve)

Seat angle 45½°
Head diameter 1.625 to 1.630 in. (41.27 to 41.40 mm)
Stem diameter 0.3429 to 0.3434 in. (8.70 to 8.72 mm)
Stem to guide clearance 0.0008 to 0.0018 in. (0.020 to 0.046 mm)

18V Engine — Later Cars (Inlet and Exhaust)

Head diameter — inlet 1.562 to 1.567 in. (39.67 to 39.80 mm)
Head diameter — exhaust 1.343 to 1.348 in. (34.11 to 34.23 mm)
Stem diameter — inlet 0.3429 to 0.3434 in. (8.70 to 8.72 mm)
Stem diameter — exhaust 0.3423 to 0.3428 in. (8.69 to 8.70 mm)
Stem to guide clearance — inlet 0.0007 to 0.0019 in. (0.020 to 0.045 mm)
Stem to guide clearance — exhaust 0.0013 to 0.0025 in. (0.03 to 0.06 mm)

Valve Guides

18G / 18GA

Length — inlet 1&frac58; in. (41.275 mm)
Length — exhaust 2¼ in. (55.95 mm)
Outside diameter — inlet and exhaust .5635 to .5640 in. (14.30 to 14.32 mm)
Inside diameter — inlet and exhaust .3442 to .3447 in. (8.73 to 8.74 mm)
Fitted height above head — inlet and exhaust 5/8 in. (15.875 mm)
Interference fit in head — inlet and exhaust .0005 to .00175 in. (.012 to .044 mm)
Length — inlet (later cars) 1¾ in. (47.63 mm)
Fitting height above head — inlet (later cars) ¾ in. (19 mm)

Valve Springs

18G / 18GA (Inner and Outer Springs)

Free length — inner 1&frac78; in. (50.0 mm)
Free length — outer 2&frac18; in. (54.4 mm)
Fitted length — inner 1&frac716; in. (36.5 mm)
Fitted length — outer 1&frac916; in. (39.7 mm)
Load at fitted length — inner 28 to 32 lb. (12.7 to 14.5 kg.)
Load at fitted length — outer 72 lb. (32.7 kg.)
Load at top of lift — inner 48 to 52 lb. (21.7 to 23.6 kg.)
Load at top of lift — outer 117 lb. (53 kg.)
Valve crash speed 6,200 r.p.m.

18V Engine (Single Spring)

Free length 1.92 in. (48.77 mm)
Fitted length 1.44 in. (36.58 mm)
Load at fitted length 82 lb. (37.2 kg.)
Load at top of lift 142 lb. (64.4 kg.)

Valve Timing

18G / 18GA

Timing marks Dimples on camshaft and crankshaft wheels
Rocker clearance — running .015 in. (.38 mm) cold
Rocker clearance — timing .055 in. (1.4 mm)
Inlet valve opens 16° B.T.D.C.
Inlet valve closes 56° A.B.D.C.
Exhaust valve opens 51° B.B.D.C.
Exhaust valve closes 21° A.T.D.C.

Engine Lubrication

18G / 18GA

System Wet sump, pressure fed
System pressure — running 50 to 80 lb./sq. in. (3.51 to 5.6 kg./cm.²)
System pressure — idling 10 to 25 lb./sq. in. (.7 to 1.7 kg./cm.²)
Oil pump type Hobourn-Eaton or eccentric rotor
Oil pump capacity 3¼ gal./min. at 2,000 r.p.m.
Oil filter Tecalemit full-flow felt element
By-pass valve opens 13 to 17 lb./sq. in. (.9 to 1.1 kg./cm.²)
Oil pressure relief valve 70 lb./sq. in. (4.9 kg./cm.²)
Relief valve spring — free length 3 in. (76.2 mm)
Relief valve spring — fitted length 2&frac316; in. (54.7 mm)
Relief valve spring — load at fitted length 15.5 to 16.5 lb. (7.0 to 7.4 kg.)

Fuel System

18G / 18GA

Carburetters Twin S.U. type HS4
Choke diameter 1½ in. (38.1 mm)
Jet size .090 in. (2.2 mm)
Needles No. 5 (Standard), No. 6 (Rich), No. 21 (Weak)
Piston spring Red
Air cleaners Copper paper element
Fuel pump type — early cars S.U. electric HP
Minimum flow (early pump) 7 gal./hr. (31.8 litres/hr., 8.4 U.S. gal./hr.)
Suction head (early pump) 2 ft. 6 in. (76.2 cm)
Delivery head (early pump) 4 ft. (122 cm)
Minimum starting voltage (early pump) 9.5 volts
Fuel pump type — later cars S.U. electric AUF 300
Minimum flow (later pump) 15 gal./hr. (68.2 litres/hr., 18 U.S. gal./hr.)
Suction head (later pump) 18 in. (457 mm)

18GB

Carburetter needles FX (Standard), No. 6 (Rich), No. 21 (Weak)

18GD / 18GG

Carburetter needles FX (Standard), No. 6 (Rich), GZ (Weak)

Emission Control Engine Types — Carburetter Needles

18GF FX
18GH – 18GJ AAE
18GK AAL
18V 5842 and 18V 5852 AAU
18V 6722 and 18V 6732 ABO

Emission Control — Fuel Tank Capacity

Fuel tank capacity (18GJ and 18GK engines) 12 U.S. gallons (45.4 litres)

Cooling System

18G / 18GA

Type Pressurized, pump-impeller and fan-assisted
Thermostat setting — standard 74°C. (165°F.)
Thermostat setting — hot climate 74°C. (165°F.)
Thermostat setting — cold climate 82°C. (180°F.)
Pressure cap 7 lb. (3.175 kg.)
Fan blades 3 at 24°
Fan belt — width ½ in. (9.5 mm)
Fan belt — outside length 35½ in. (90.2 cm)
Fan belt — thickness ¼ in. (7.9 mm) approx.
Fan belt — tension ½ in. (12.8 mm) movement
Pump type Centrifugal
Pump drive Belt from crankshaft pulley

18GD / 18GG

Fan belt — width 15/32 in. (11.9 mm)
Fan belt — length 35½ in. (90.2 cm) at 3/8 in. width equivalent
Fan belt — thickness 27/64 in. (10.7 mm)
Fan belt — tension ½ in. (12.8 mm) movement at midway of longest run
Thermostat — normal 82°C. (180°F.)
Thermostat — hot climates 74°C. (165°F.)
Thermostat — cold climates 88°C. (190°F.)

Ignition System

18G / 18GA

Coil HA.12 (oil-filled)
Coil primary resistance at 20°C. (68°F.) 3.1 to 3.5 ohms (cold)
Coil consumption — ignition switch on 3.9 amps
Coil consumption 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° ± 3°
Cam opened period 30° ± 3°
Automatic advance Centrifugal and vacuum
Automatic advance commences — H.C. (Serial No. 40897) and L.C. (Serial No. 40916) 400 r.p.m. (both)
Maximum advance — H.C. (crankshaft degrees) 20° at 2,000 r.p.m.
Maximum advance — L.C. (crankshaft degrees) 24° at 4,400 r.p.m.
Vacuum advance — H.C. 20° at 13 in. (33.3 cm) Hg
Vacuum advance — L.C. 16° at 12 in. (30.5 cm) Hg
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)
Static ignition timing — L.C. 8° B.T.D.C. (95/97-octane fuel)
Stroboscopic ignition timing — H.C. 14° B.T.D.C. at 600 r.p.m.
Stroboscopic ignition timing — 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
Plug size 14 mm, 3/4 in. (19.0 mm) reach
Plug gap .024 to .026 in. (.625 to .660 mm)

Emission Control Engine Types — Distributor Serial Numbers

Make/type Lucas 25D4
18GF Serial No. 40897
18GH – 18GJ Serial No. 41155
18GK Serial No. 41339
18V 5842 and 18V 5852 Serial No. 41370
18V 6722 and 18V 6732 Serial No. 41491

Clutch

18G / 18GA

Make and type Borg & Beck 8 in. D.S.G. diaphragm spring
Diaphragm spring colour Dark blue
Clutch plate diameter 8 in. (20.32 cm)
Facing material Wound yarn
Number of damper springs 6
Damper spring load 110 to 120 lb. (49.8 to 54.3 kg.)
Damper spring colour Black/light green
Clutch release bearing Graphite (MY3D)
Clutch fluid Lockheed Disc Brake Fluid (Series II)

18GD / 18GG

Clutch fluid Lockheed Disc Brake Fluid (Series 329)

Gearbox and Overdrive

18G / 18GA

Number of forward gears 4
Gearbox ratio — reverse 4.76 : 1
Gearbox ratio — first 3.64 : 1
Gearbox ratio — second 2.21 : 1
Gearbox ratio — third 1.37 : 1
Gearbox ratio — fourth 1.00 : 1
Overdrive ratio .802 : 1
Overall ratio — reverse 18.588 : 1
Overall ratio — first 14.214 : 1
Overall ratio — second 8.656 : 1
Overall ratio — third 5.369 : 1 (overdrive: 4.306 : 1)
Overall ratio — fourth 3.909 : 1 (overdrive: 3.135 : 1)
Top gear speed per 1,000 r.p.m. — standard 17.9 m.p.h. (27.3 km.p.h.)
Top gear speed per 1,000 r.p.m. — overdrive 22.3 m.p.h. (35.5 km.p.h.)
Speedometer gear ratio — standard 9/28
Speedometer gear ratio — overdrive 5/16
Synchromesh hub springs — free length ½ in. (12.7 mm)
Synchromesh hub springs — fitted length 5/16 in. (7.9 mm)
Synchromesh hub springs — load at fitted length 4 to 5 lb. (1.8 to 2.2 kg.)
Shaft and reverse plunger detent springs — free length 1¼ in. (30.16 mm)
Shaft and reverse plunger detent springs — fitted length ¾ in. (19.0 mm)
Shaft and reverse plunger detent springs — load at fitted length 18 to 20 lb. (8.16 to 9.07 kg.)
Reverse plunger springs — free length 1 in. (25.4 mm)
Reverse plunger springs — fitted length 13/16 in. (20.63 mm)
Reverse plunger springs — load at fitted length 91½ to 92½ lb. (41.4 to 41.9 kg.)
Mainshaft second and third gear end-float .004 to .006 in. (.10 to .15 mm)
Laygear end-float .002 to .003 in. (.05 to .08 mm)
Overdrive pump spring — free length 2.000 in. (50.8 mm)
Overdrive pump spring — rate 11 lb. in. (12.7 kg.cm.)
Overdrive clutch spring — free length 1.510 in. (38.3 mm)
Overdrive clutch spring — rate 154 lb. in. (178 kg.cm.)

18GD / 18GG (Synchromesh Gearbox)

Number of forward gears 4
Synchromesh All forward gears
Gearbox ratio — reverse 3.095 : 1
Gearbox ratio — first 3.44 : 1
Gearbox ratio — second 2.167 : 1
Gearbox ratio — third 1.382 : 1
Gearbox ratio — fourth 1.000 : 1
Overdrive type Laycock L.H.
Overdrive ratio .82 : 1
Overall ratio — reverse 12.098 : 1
Overall ratio — first 13.45 : 1
Overall ratio — second 8.47 : 1
Overall ratio — third 5.4 : 1 (overdrive: 4.43 : 1)
Overall ratio — fourth 3.909 : 1 (overdrive: 3.2 : 1)
Top gear speed per 1,000 r.p.m. — standard 18 m.p.h. (29 km.p.h.)
Top gear speed per 1,000 r.p.m. — overdrive 22 m.p.h. (35 km.p.h.)
Speedometer gear ratio — standard 10 : 26
Speedometer gear ratio — overdrive 8 : 21
Synchromesh hub springs — free length .72 in. (18.3 mm)
Synchromesh hub springs — fitted length .385 in. (9.8 mm)
Synchromesh hub springs — load at fitted length 5.5 to 6 lb. (2.5 to 2.7 kg.)
First and third speed gear end-float .005 to .008 in. (.13 to .20 mm)
Second gear end-float .005 to .008 in. (.13 to .20 mm)
Laygear end-float .002 to .003 in. (.05 to .08 mm)

18GD / 18GG (Automatic Gearbox)

Torque converter ratio 2.2 : 1 to 1 : 1
Gearbox ratio — reverse 2.09 : 1
Gearbox ratio — first 2.39 : 1
Gearbox ratio — second 1.45 : 1
Gearbox ratio — top 1.00 : 1
Overall ratio (converter at 1:1) — reverse 8.17 : 1
Overall ratio (converter at 1:1) — first 9.34 : 1
Overall ratio (converter at 1:1) — second 5.668 : 1
Overall ratio (converter at 1:1) — top 3.909 : 1
Speedometer gear ratio 10 : 26

Propeller Shaft

18G / 18GA

Type Open tubular, telescopic
Universal joints Hardy Spicer needle roller
Angular movement 18° to 20°
Overall length fully extended — standard 30¾ in. (78.1 cm)
Overall length fully extended — overdrive 31¼ in. (81 cm)
Overall length fully compressed — standard 29¼ in. (74 cm)
Overall length fully compressed — overdrive 30¼ in. (76.5 cm)
Length of shaft assembly — standard 25½ in. (64.3 cm)
Length of shaft assembly — overdrive 26&frac316; in. (67 cm)
Tube diameter 2 in. (50.8 mm)

Rear Axle

18G / 18GA (Three-Quarter-Floating)

Type Hypoid, three-quarter-floating
Ratio 3.909 : 1 (11/43)
Differential bearing preload .002 in. (.05 mm) nip per bearing
Pinion bearing preload 7 to 9 lb. in. (.8 to 1.0 kg.m.)
Backlash adjustment — crown wheel Shims
Backlash adjustment — pinion Head washer

18GB — GT (Semi-Floating)

Type Hypoid, semi-floating
Ratio 3.909 : 1 (11/43)
Differential bearing preload .002 in. (.05 mm) nip per bearing
Pinion bearing preload — new collapsible spacer only 14 to 18 lb. in. (.161 to .207 kg.m.)
Pinion bearing preload — oil seal change, spacer collapsed Adjust to preload — refer Section Ha.4
Backlash adjustment — crown wheel Shims
Backlash adjustment — pinion Head washer

18GD / 18GG (Semi-Floating)

Type Hypoid, semi-floating
Ratio 3.909 : 1 (11/43)
Differential bearing preload .002 in. (.05 mm) nip per bearing
Pinion bearing preload Refer to Section Ha.4
Backlash adjustment — crown wheel Shims
Backlash adjustment — pinion Head washer

Steering

18G / 18GA

Type Rack and pinion
Steering-wheel diameter 16½ in. (419.10 mm)
Turns lock to lock 2.93
Turning circle 32 ft. (9.75 m)
Universal joint Hardy Spicer KO518, GB 166
Pinion end-float .002 to .005 in. (.05 to .12 mm)
Damper end-float (unladen) .0005 to .003 in. (.012 to .076 mm)
Toe-in (unladen) 1/16 to 3/32 in. (1.5 to 2.3 mm)
Angle of outer wheel with inner wheel at 20° 19° ± 1°

Front Suspension

18G / 18GA (Tourer)

Type Independent, coil spring and wishbone
Spring coil diameter (mean) 3.238 in. (82.2 mm)
Spring free height 9.9 ± 1/16 in. (251.4 ± 1.5 mm)
Static length at 1,030 lb. (467.2 kg.) load 7 ± 1/32 in. (178 ± .8 mm)
Number of free coils 7.5
Camber angle Nominal 1° positive (+¼°, −1¼°) = ¾° to 1¼° positive (unladen)
Castor angle Nominal 7° (+¼°, −2°) = 5° to 7¼° (unladen)
King pin inclination Nominal 8° (+1°, −¾°) = 7¼° to 9°
Dampers Armstrong piston type
Damper arm centres 8 in. (203.2 mm)
Wheel bearing end-float .002 to .004 in. (.05 to .10 mm)

18GB (GT)

Spring coil diameter (mean) 3.28 in. (83.3 mm)
Spring free height 9.1 ± 1/16 in. (231 ± 1.6 mm)
Number of free coils 7.2
Static length at load of 1,193 lb. (541.5 kg.) ± 20 lb. (9.1 kg.) 6.6 in. (168 mm)

18V Engine — Tourer from Car No. 293446

Free height 10.20 ± 0.06 in. (259.08 ± 1.5 mm)
Static length at load of 1,030 ± 20 lb. (467 ± 9 kg.) 7.24 in. (187.70 mm)
No. of free coils 7.5

18V Engine — Tourer, Later Cars

Free height (nominal) 10.20 in. (259.08 mm)
Static length at load of 1,030 ± 20 lb. (467 ± 9 kg.) 7.44 in. (188.98 mm)
No. of free coils 9

18V Engine — GT from Car No. 296196

Free height 9.32 ± ¼ in. (236.73 ± 1.6 mm)
Static length at load of 1,193 ± 20 lb. (541 ± 9 kg.) 6.84 in. (173.74 mm)
No. of free coils 7.2

Rear Suspension

18G / 18GA (Tourer)

Type Semi-elliptic leaf spring
Number of spring leaves 5 + bottom plate; interleaving 1/2, 2/3, 3/4
Width of spring leaves 1¾ in. (44.4 mm)
Gauge of leaves — early cars 7/32 in. (5.56 mm)
Gauge of leaves — later cars 3 at 7/32 in. (5.6 mm), 3 at 3/16 in. (4.8 mm)
Working load (±15 lb. [7 kg.]) — early cars 400 lb. (181.5 kg.)
Working load (±15 lb. [7 kg.]) — later cars 450 lb. (204.1 kg.)
Dampers Armstrong piston type
Damper arm centres 5¼ in. (133 mm)

18GB (GT)

Working load (±15 lb. [7 kg.]) 510 lb. (231.6 kg.)

18V Engine

Number of spring leaves 6, interleaving between 1/2, 2/3
Width of spring leaves 1.76 in. (44.7 mm)
Gauge of leaves — 1st, 2nd, 3rd 0.2187 ± 0.006 in. (5.55 ± 0.152 mm)
Gauge of leaves — 4th, 5th, 6th 0.1875 ± 0.006 in. (4.75 ± 0.152 mm)
Working load 510 to 540 lbf. (231 to 245 kgf.)

Electrical Equipment

18G / 18GA — System

System voltage and earth 12-volt, positive earth
Charging system Current/voltage control

18G / 18GA — Batteries (Two 6-Volt)

Type — early cars Lucas SG9E or STGZ9E
Type — later cars Lucas BT9E or BTZ9E
Capacity — 10-hour rate 51 amp.-hr.
Capacity — 20-hour rate 58 amp.-hr.
Plates per cell 9
Electrolyte to fill one cell 1 pint (570 c.c., 1.2 U.S. pints)

18G / 18GA — Regulator (RB.340)

Voltage setting at 3,000 r.p.m. at 10°C. (50°F.) 14.9 to 15.5 volts
Voltage setting at 3,000 r.p.m. at 20°C. (68°F.) 14.7 to 15.3 volts
Voltage setting at 3,000 r.p.m. at 30°C. (86°F.) 14.5 to 15.1 volts
Voltage setting at 3,000 r.p.m. at 40°C. (104°F.) 14.3 to 14.9 volts
Current setting at 4,000 r.p.m. 22 amps
Cut-out relay — cut-in voltage 12.7 to 13.3 volts
Cut-out relay — drop-off voltage 9.5 to 11.0 volts
Reverse current 3.0 to 5.0 amps
Current regulator 22 ± 1 amp

18G / 18GA — Dynamo (C40/1)

Type C40/1, 12-volt two-brush
Maximum output 22 amps
Cut-in speed 1,585 r.p.m. at 13.0 volts
Field resistance 6.0 ohms
Brush spring tension 22 to 25 oz. (623 to 708 gm.)
Drive Belt from crankshaft
Drive adjustment Swinging link on dynamo

18G / 18GA — Starter Motor (M418G Inertia Type)

Type M418G four-brush inertia type
Lock torque 15 lb. ft. (2.1 kg.m.) at 425 amps
Torque at 1,000 r.p.m. 8 lb. ft. (1.11 kg.m.) at 250 to 270 amps
Brush spring tension 32 to 40 oz. (907 to 1,133 gm.)
Starter gear ratio 13.3 : 1

18G / 18GA — Wiper Motor (DR.3A)

Type DR.3A single speed
Drive to wheelboxes Rack and cable
Armature end-float .008 to .012 in. (.20 to .30 mm)
Running current 2.7 to 3.4 amps
Wiping speed 45 to 50 cycles per minute

18G / 18GA — Horns

Type 9H 12-volt
Maximum current consumption 3½ amps

18GD / 18GG — System

System voltage and earth 12-volt, negative earth

18GD / 18GG — Batteries (Two 6-Volt)

Type — early cars Lucas BT9E or BTZ9E
Type — later cars Lucas CA9E
Capacity — 10-hour rate (early) 51 amp.-hour
Capacity — 10-hour rate (later) 53 amp.-hour
Capacity — 20-hour rate (early) 58 amp.-hour
Capacity — 20-hour rate (later) 60 amp.-hour
Plates per cell 9
Electrolyte to fill one cell 1 pint (570 c.c., 1.2 U.S. pints)

18GD / 18GG — Control Box (4TR Electronic)

Type 4TR Electronic
Voltage setting 14.3 to 14.7 volts at 5,000 r.p.m.

18GD Engine — Alternator (Lucas 16AC)

Type Lucas 16AC
Output at 14 volts and 6,000 r.p.m. 34 amps
Maximum permissible rotor speed 12,500 r.p.m.
Pulley ratio — alternator/crankshaft 1.795 : 1
Stator phases 3
Rotor poles 12
Rotor winding resistance 4.33 ohms ± 5% at 20°C. (68°F.)
Brush length (new) ½ in. (12.6 mm)
Brush spring tension 7 to 10 oz. (198 to 283 gm.) with brush face flush with brush box

18GG Engine — Alternator (Lucas 16ACR)

Type Lucas 16ACR
Output and specifications Data as 16AC (above)

18GD / 18GG — Starter Motor (Lucas M418G Pre-Engaged)

Type Lucas M418G Pre-engaged
Light running current 70 amp. at 5,800 to 6,500 r.p.m.
Lock torque 17 lb. ft. (2.35 kg.m.) at 465 amps
Torque at 1,000 r.p.m. 7 lb. ft. (.97 kg.m.) at 260 amps
Solenoid closing coil resistance .13 to .15 ohm
Solenoid hold-on coil resistance .63 to .73 ohm
Brush spring tension 36 oz. (1.02 kg.)

18GD / 18GG — Starter Motor Relay (Lucas 6RA)

Type Lucas Model 6RA – 33243
Winding resistance 76 ohms
Air gap — contacts open .030 ± .005 in. (.76 ± .13 mm)
Air gap — contacts closed .010 ± .003 in. (.25 ± .08 mm)
Cut-in voltage 4.0 to 7.5 volts
Drop-off voltage 5 volts (maximum)

18GD / 18GG — Wiper Motor (Lucas 14W Two-Speed)

Type Lucas 14W (two-speed)
Armature end-float .004 to .008 in. (.10 to .21 mm)
Light running current — normal speed 1.5 amp
Light running current — high speed 2.0 amp
Light running speed — normal 46 to 52 r.p.m.
Light running speed — high 60 to 70 r.p.m.

18V Engine — Starter Motor (Lucas 2M 100)

Type Lucas 2M 100 Pre-engaged
Brush spring tension 36 oz. (1.02 kg.)
Minimum brush length 3/8 in. (9.5 mm)
Minimum commutator thickness 0.140 in. (3.5 mm)
Lock torque 14.4 lb. ft. (2.02 kg.m.) with 463 amps
Torque at 1,000 r.p.m. 7.3 lb. ft. (1.02 kg.m.) with 300 amps
Light running current 40 amp. at 6,000 r.p.m. (approx.)
Maximum armature end-float 0.010 in. (0.25 mm)
Solenoid closing (series) winding resistance 0.25 to 0.27 ohm
Solenoid hold-on (shunt) winding resistance 0.76 to 0.80 ohm

Brakes

18G / 18GA

Type Lockheed hydraulic — disc front, drum rear
Brake fluid Lockheed Disc Brake Fluid (Series II)
Front disc diameter 10¾ in. (27.3 cm)
Front pad material Don 55-FF
Front swept area 203.2 sq. in. (1,311 cm.²)
Rear drum diameter 10 in. (25.4 cm)
Rear lining material Don 24-FE
Rear swept area 106.8 sq. in. (683.9 cm.²)
Rear lining dimensions 9&frac1116; × 1¾ × 3/16 in. (240 × 44.4 × 4.76 mm)

18GD / 18GG

Brake fluid Lockheed Disc Brake Fluid (Series 329)

Wheels

18G / 18GA (Tourer)

Type Ventilated disc, 4-stud fixing; wire (optional)
Size — disc 4J × 14
Size — wire 4½J × 14

18GB (GT)

Size — disc 5J × 14 in.

18GD / 18GG

Pressed disc — Tourer 4½ × 14
Pressed disc — GT 5½ × 14
Pressed spoked 5½ F/H × 14
Wire (optional) 4½J × 14 (60-spoke)

Tyres

18G / 18GA (Tourer)

Standard size 5.60-14 (tubed)
Rolling radius (standard, at 30 m.p.h.) 11.65 in. (29.5 cm)
Optional size 155-14

18GB (GT)

Optional size — early cars 165-14 SP41
Optional size — later cars 165-14 SP68

Tyre Pressures

18G / 18GA (Tourer)

Standard 5.60-14 — normal weight, front 18 lb./sq. in. (1.3 kg./cm.²)
Standard 5.60-14 — normal weight, rear 18 lb./sq. in. (1.3 kg./cm.²)
Standard 5.60-14 — sustained speeds over 90 m.p.h., front 24 lb./sq. in. (1.7 kg./cm.²)
Standard 5.60-14 — sustained speeds over 90 m.p.h., rear 24 lb./sq. in. (1.7 kg./cm.²)
Optional 155-14 — normal weight, front 21 lb./sq. in. (1.5 kg./cm.²)
Optional 155-14 — normal weight, rear 24 lb./sq. in. (1.7 kg./cm.²)
Optional 155-14 — sustained speeds over 90 m.p.h., front 27 lb./sq. in. (1.9 kg./cm.²)
Optional 155-14 — sustained speeds over 90 m.p.h., rear 31 lb./sq. in. (2.2 kg./cm.²)

Rear tyre pressures may be increased by 2 lb./sq. in. (.14 kg./cm.²) when towing with a laden boot.

18GB (GT) — Standard Tyres (set cold)

Normal weight, front 20 lb./sq. in. (1.4 kg./cm.²)
Normal weight, rear 24 lb./sq. in. (1.7 kg./cm.²)
Sustained speeds over 90 m.p.h., front 26 lb./sq. in. (1.8 kg./cm.²)
Sustained speeds over 90 m.p.h., rear 30 lb./sq. in. (2.1 kg./cm.²)

18GB (GT) — Optional Tyres (set cold)

Normal weight, front 21 lb./sq. in. (1.5 kg./cm.²)
Normal weight, rear 24 lb./sq. in. (1.7 kg./cm.²)
Sustained speeds over 90 m.p.h., front 28 lb./sq. in. (2.0 kg./cm.²)
Sustained speeds over 90 m.p.h., rear 31 lb./sq. in. (2.2 kg./cm.²)

18GD / 18GG (Tourer) — 5.60-14S Cross-Ply

Normal car weight, front 19 lb./sq. in. (1.34 kg./cm.²)
Normal car weight, rear 22 lb./sq. in. (1.55 kg./cm.²)
Maximum weight, front 19 lb./sq. in. (1.34 kg./cm.²)
Maximum weight, rear 24 lb./sq. in. (1.69 kg./cm.²)

18GD / 18GG (Tourer) — 155SR-14 Radial-Ply

Normal car weight, front 21 lb./sq. in. (1.48 kg./cm.²)
Normal car weight, rear 24 lb./sq. in. (1.69 kg./cm.²)
Maximum weight, front 21 lb./sq. in. (1.48 kg./cm.²)
Maximum weight, rear 26 lb./sq. in. (1.83 kg./cm.²)

18GD / 18GG (GT)

Normal car weight, front 20 lb./sq. in. (1.4 kg./cm.²)
Normal car weight, rear 24 lb./sq. in. (1.69 kg./cm.²)
Maximum weight, front 20 lb./sq. in. (1.4 kg./cm.²)
Maximum weight, rear 26 lb./sq. in. (1.83 kg./cm.²)
Tyre size (GT) 165SR-14 (pressures as Tourer above)

For sustained speeds at or near maximum, increase the above tyre pressures by 6 lb./sq. in. (.42 kg./cm.²).


Capacities

18G / 18GA

Fuel tank — early cars 10 gallons (45.4 litres, 12 U.S. gallons)
Fuel tank — later cars 12 gallons (54 litres, 14 U.S. gallons)
Cooling system 9½ pints (5.4 litres, 11.4 U.S. pints)
Heater ½ pint (.28 litre, .6 U.S. pint)
Engine sump 7½ pints (4.26 litres, 9 U.S. pints)
Oil cooler ¾ pint (.42 litre, .9 U.S. pint)
Gearbox 4½ pints (2.56 litres, 5.6 U.S. pints)
Gearbox and overdrive 6 pints (3.36 litres, 6 U.S. pints)
Rear axle 2¼ pints (1.28 litres, 2.75 U.S. pints)
Steering rack ½ pint (.19 litre, .39 U.S. pint)

18GB — Additional

Rear axle (semi-floating type) 1¼ pints (.85 litre, 2 U.S. pints)

18GD / 18GG

Gearbox 5¼ pints (3 litres, 6 U.S. pints)
Gearbox and overdrive 6 pints (3.4 litres, 7 U.S. pints)
Automatic gearbox 10½ pints (6 litres, 12.7 U.S. pints)
Rear axle 1½ pints (.85 litres, 2 U.S. pints)

18V Engine — GHN5/GHD5 from Car No. 410002

Fuel tank 12 gallons (54.5 litres, 14.4 U.S. gallons)
Cooling system 11½ pints (6.6 litres, 13.8 U.S. pints)
Cooling system with heater 12 pints (6.8 litres, 14.4 U.S. pints)

Dimensions

18G / 18GA

Overall length 12 ft. 8½ in. (3.874 m)
Overall length (with over-riders) 12 ft. 9¼ in. (3.897 m)
Overall width 4 ft. 11&frac516; in. (152.3 cm)
Overall height — hood erected 4 ft. 1&frac38; in. (125.4 cm)
Ground clearance (minimum) 5 in. (12.7 cm)
Wheelbase 7 ft. 7 in. (231.1 cm)
Track — front (disc wheels) 4 ft. 1 in. (124.4 cm)
Track — rear (disc wheels) 4 ft. 1¼ in. (125 cm)
Track — front (wire wheels) 4 ft. 1¼ in. (125 cm)
Track — rear (wire wheels) 4 ft. 1¼ in. (125 cm)

18GB (GT)

Overall height (GT) 4 ft. 1¾ in. (126.3 cm)

18V Engine — GHN5/GHD5 from Car No. 410002

Track — front 4 ft. 1½ in. (124.7 cm)
Track — rear 4 ft. 1¾ in. (126.4 cm)

Weights

18G / 18GA

Unladen weight 1,920 lb. (871 kg.)
Engine (dry, with clutch) 358 lb. (163.3 kg.) approx.
Gearbox 78 lb. (35.5 kg.) approx.
Rear axle — disc wheels 117½ lb. (53.26 kg.) approx.
Rear axle — wire wheels 123 lb. (55.79 kg.) approx.

18GB (GT)

Unladen weight (GT) 2,190 lb. (993 kg.)

18GD / 18GG

Kerbside weight — Tourer 2,303 lb. (1,044 kg.)
Kerbside weight — GT 2,401 lb. (1,088 kg.)
Normal weight (kerbside + driver, passenger, 50 lb. luggage) — Tourer 2,653 lb. (1,203 kg.)
Normal weight — GT 2,751 lb. (1,248 kg.)
Maximum weight (normal + towbar hitch load) — Tourer 2,753 lb. (1,249 kg.)
Maximum weight — GT 2,851 lb. (1,293 kg.)
Maximum permissible towing weight — Tourer and GT 1,680 lb. (762 kg.)
Maximum towbar hitch load — Tourer and GT 100 lb. (45 kg.)

18V Engine (GHN5/GHD5)

Kerbside weight — Tourer 2,394 lb. (1,088 kg.)
Kerbside weight — GT 2,446 lb. (1,110 kg.)
Normal weight (kerbside + driver and passenger) — Tourer 2,694 lb. (1,223 kg.)
Normal weight — GT 2,746 lb. (1,245 kg.)
Gross weight — Tourer 2,814 lb. (1,277 kg.)
Gross weight — GT 2,866 lb. (1,301 kg.)
Maximum permissible towing weight — Tourer and GT 1,680 lb. (762 kg.)
Maximum towbar hitch load — Tourer and GT 100 lb. (45 kg.)
Maximum roof rack load (GT only) 50 lb. (23 kg.)

Torque Wrench Settings

18G / 18GA — Engine

Main bearing nuts 70 lb. ft. (9.7 kg.m.)
Flywheel set screws 40 lb. ft. (5.5 kg.m.)
Gudgeon pin clamp bolt 25 lb. ft. (3.4 kg.m.)
Big-end bolts 35 to 40 lb. ft. (4.8 to 5.5 kg.m.)
Cylinder head nuts 45 to 50 lb. ft. (6.2 to 6.9 kg.m.)
Rocker bracket nuts 25 lb. ft. (3.4 kg.m.)
Oil pump to crankcase 14 lb. ft. (1.9 kg.m.)
Sump to crankcase 6 lb. ft. (.8 kg.m.)
Cylinder side cover screws 2 lb. ft. (.28 kg.m.)
Cylinder side cover screws (second type, deep pressed cover) 5 lb. ft. (.7 kg.m.)
Timing cover — 1/4 in. screws 6 lb. ft. (.8 kg.m.)
Timing cover — 5/16 in. screws 14 lb. ft. (1.9 kg.m.)
Rear plate — 5/16 in. screws 20 lb. ft. (2.8 kg.m.)
Rear plate — 3/8 in. screws 30 lb. ft. (4.1 kg.m.)
Water pump to crankcase 17 lb. ft. (2.4 kg.m.)
Water outlet elbow nuts 8 lb. ft. (1.1 kg.m.)
Rocker cover nuts 4 lb. ft. (.56 kg.m.)
Manifold nuts 15 lb. ft. (2.1 kg.m.)
Oil filter centre-bolt 15 lb. ft. (2.1 kg.m.)
Clutch to flywheel 25 to 30 lb. ft. (3.4 to 4.1 kg.m.)
Carburetter stud nuts 2 lb. ft. (.28 kg.m.)
Distributor clamp bolt (nut trapped) 4.16 lb. ft. (.57 kg.m.)
Distributor clamp nut (bolt trapped) 2.5 lb. ft. (.35 kg.m.)
Fan blade fixing screws 7.3 to 9.3 lb. ft. (1.0 to 1.3 kg.m.)

18G / 18GA — Rear Axle

Crown wheel to differential carrier 55 to 60 lb. ft. (7.6 to 8.3 kg.m.)
Differential bearing cap 60 to 65 lb. ft. (8.3 to 8.9 kg.m.)
Pinion bearing nut 135 to 140 lb. ft. (18.6 to 19.3 kg.m.)
Rear brake adjuster securing nuts 5 to 7 lb. ft. (.69 to .97 kg.m.)
Bearing retaining nut 180 lb. ft. (24.8 kg.m.)

18G / 18GA — Rear Suspension

Rear shock absorber bolts 55 to 60 lb. ft. (7.6 to 8.3 kg.m.)

18G / 18GA — Front Suspension

Front shock absorber bolts 43 to 45 lb. ft. (5.9 to 6.2 kg.m.)
Brake disc to hub 40 to 45 lb. ft. (5.5 to 6.2 kg.m.)
Brake calliper mounting 40 to 45 lb. ft. (5.5 to 6.2 kg.m.)
Bearing retaining nut 40 to 70 lb. ft. (5.5 to 9.7 kg.m.)
Cross-member to body 54 to 56 lb. ft. (7.5 to 7.7 kg.m.)

18G / 18GA — Steering

Steering arm bolts 60 to 65 lb. ft. (8.3 to 8.9 kg.m.)
Steering wheel nut 41 to 43 lb. ft. (5.7 to 5.9 kg.m.)
Steering tie-rod lock nut 33.3 to 37.5 lb. ft. (4.6 to 5.2 kg.m.)
Steering lever ball joint nut 34 to 35 lb. ft. (4.7 to 4.8 kg.m.)
Steering universal joint bolt 20 to 22 lb. ft. (2.8 to 3.0 kg.m.)

18G / 18GA — Road Wheels

Road wheel nuts 60 to 65 lb. ft. (8.3 to 9.0 kg.m.)

18GB — Rear Axle

Half-shaft nut (semi-floating axle) 150 lb. ft. (20.75 kg.m.)
Differential bearing cap bolts 50 to 55 lb. ft. (6.9 to 7.6 kg.m.)
Crown wheel bolts 60 to 65 lb. ft. (8.3 to 8.9 kg.m.)
Pinion nut — new spacer only 180 to 220 lb. ft. (28.89 to 30.42 kg.m.)
Pinion nut — oil seal change Adjust to preload — see Section Ha
Axle shaft nut 150 lb. ft. (20.6 kg.m.) aligned to next split pin hole

18GD / 18GG — Automatic Gearbox

Converter to drive plate bolts 25 to 30 lb. ft. (3.46 to 4.15 kg.m.)
Transmission case to converter housing bolts 8 to 13 lb. ft. (1.1 to 1.8 kg.m.)
Extension housing to transmission case bolts 8 to 13 lb. ft. (1.1 to 1.8 kg.m.)
Oil pan to gearbox bolts 8 to 13 lb. ft. (1.1 to 1.8 kg.m.)
Front servo bolts 8 to 13 lb. ft. (1.1 to 1.8 kg.m.)
Rear servo bolts 13 to 27 lb. ft. (1.8 to 3.73 kg.m.)
Pump adaptor to housing screw 2 to 3 lb. ft. (.28 to .41 kg.m.)
Pump adaptor to housing bolts 17 to 32 lb. ft. (2.35 to 4.43 kg.m.)
Pump adaptor to transmission case bolts 8 to 18.5 lb. ft. (1.1 to 2.55 kg.m.)
Manual shaft locknut 7 to 9 lb. ft. (.97 to 1.24 kg.m.)
Pressure adaptor plug 4 to 5 lb. ft. (.55 to .69 kg.m.)
Drain plug 8 to 10 lb. ft. (1.1 to 1.38 kg.m.)
Upper valve body to lower valve body screws 20 to 30 lb. in. (.23 to .345 kg.m.)
Lower valve body to upper valve body screws 20 to 30 lb. in. (.23 to .345 kg.m.)
Oil tube and end plate to valve body screws 20 to 30 lb. in. (.23 to .345 kg.m.)
Valve bodies to transmission case bolts 4.5 to 9 lb. ft. (.61 to 1.24 kg.m.)
Cam bracket screws 20 to 40 lb. in. (.23 to .46 kg.m.)
Governor to counter-weight screws 4 to 5 lb. ft. (.55 to .69 kg.m.)
Governor cover-plate screws 20 to 48 lb. in. (.23 to .552 kg.m.)
Front servo adjusting screw locknut 15 to 20 lb. ft. (2.07 to 2.77 kg.m.)
Rear servo adjusting screw locknut 25 to 30 lb. ft. (3.46 to 4.15 kg.m.)
Starter inhibitor switch locknut 4 to 6 lb. ft. (.55 to .83 kg.m.)
Downshift cable adaptor bolts 8 to 9 lb. ft. (1.1 to 1.24 kg.m.)
Filler tube connector sleeve to transmission case 20 to 30 lb. ft. (2.76 to 4.15 kg.m.)
Filler tube to connector sleeve nut 17 to 18 lb. ft. (2.35 to 2.49 kg.m.)
Stone-guard screws 17 to 19 lb. in. (.196 to .219 kg.m.)
Driving flange nut 55 to 60 lb. ft. (7.6 to 8.3 kg.m.)
Centre support bolts 10 to 18 lb. ft. (1.38 to 2.49 kg.m.)

18GD / 18GG — General

Stiffnut to cross-member mounting bolt 44 to 46 lb. ft. (6.08 to 6.36 kg.m.)
Gearbox remote control cover to tunnel 7.5 to 9.5 lb. ft. (1.04 to 1.31 kg.m.)
Hydraulic brake pipe connection — 3/8 in. UNF 5 to 7 lb. ft. (.69 to .96 kg.m.)
Hydraulic brake pipe connection — 1/4 in. UNF 7 to 10 lb. ft. (.96 to 1.38 kg.m.)
Steering-wheel nut — 1/4 in. UNF 27 to 29 lb. ft. (3.73 to 4.01 kg.m.)
Steering-wheel nut — 5/8 in. UNF 41 to 43 lb. ft. (5.66 to 5.94 kg.m.)

18GD / 18GG — Electrical

Alternator shaft nut 25 to 30 lb. ft. (3.46 to 4.15 kg.m.)

GHN5/GHD5 — Emission Control Cars — General

Interior mirror special screw 5 lb. in. (.058 kg.m.)
Steering-column top fixing bolts 12 to 17 lb. ft. (1.66 to 2.35 kg.m.)
Steering-column universal joint bolts 20 to 22 lb. ft. (2.8 to 3.04 kg.m.)
Steering-wheel nut 36 to 38 lb. ft. (4.98 to 5.26 kg.m.)
Steering-wheel nut — 1/4 in. UNF 27 to 29 lb. ft. (3.73 to 4.00 kg.m.)
Master cylinder port adaptors 33 lb. ft. (4.56 kg.m.)
Master cylinder reservoir fixing bolts 5 lb. ft. (.69 kg.m.)
Brake pressure failure switch (nylon) 15 lb. in. (.173 kg.m.)
Brake pressure failure switch assembly end plug 200 lb. in. (2.3 kg.m.)
Hydraulic brake pipe connection — 3/8 in. UNF 5 to 7 lb. ft. (.69 to .96 kg.m.)
Hydraulic brake pipe connection — 5/16 in. UNF 7 to 10 lb. ft. (.96 to 1.38 kg.m.)

18V Engine — Engine

Big-end nuts (12-sided) 33 lbf. ft. (4.5 kgf.m.)
Crankshaft pulley nut 70 lbf. ft. (9.6 kgf.m.)
Camshaft nut 65 lbf. ft. (8.9 kgf.m.)
Carburetter stud nuts 15 lbf. ft. (2.1 kgf.m.)
Spark plugs 18 lbf. ft. (2.5 kgf.m.)
Oil pipe banjo 37 lbf. ft. maximum (5.1 kgf.m.)
Oil release valve dome nut 43 lbf. ft. (5.9 kgf.m.)
Front plate — 3/8 in. screws 20 lbf. ft. (2.8 kgf.m.)
Rear plate — 1/4 in. screws 30 lbf. ft. (4.1 kgf.m.)
Rear engine mounting bolt 38 lbf. ft. (5.22 kgf.m.)
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