LOTUS SEVEN REGISTER
the web site for the
Seven made by Lotus between 1957 and 1973
It should be noted that Climax engine, de Dion cars were not a standard factory model but more of a Seven with Mark XI running gear. They are therefore not included in these standard specifications.
September 1957 to June 1960.
CHASSIS NUMBER SEQUENCE:
400 to 499 and 750 to 892. No left hand drive cars were produced.
Approximately 243. First 100 (approx) at 7, Tottenham Lane Hornsey, London, N8. The remainder at Delamare Road, Cheshunt Hertfordshire.
Multi-tubular space-frame chassis by Progress Chassis Company of Edmonton consisting of 1" (25mm.) and 3/4" (19mm.) square and round tubing of 18 guage steel with aluminium prop shaft tunnel [NS4] and floor [L72] acting as stressed members. Floor is continuous front to rear including around engine and differential casing. Engine and gearbox rubber mounted. Transmission tunnel sides support gearbox mounting.
All aluminium clad body [Generally NS3 fixed with "Monel" steel rivets] with cycle type wings to front by Williams and Pritchard of Edmonton. G.R.P. clamshell front wings and tubular bumpers on Lotus Seven "America" model (U.S. market) from around January 1960.Nearly all cars left the factory in an unpainted state for polishing or painting as required by the purchaser. The raw state of the body of the car, as delivered, can be seen in some contemporary photographs where the joints in the rear wings and nosecone are clearly evident.
Independant by transverse wishbones incorporating anti-rollbar utilising Standard 10 vertical links, Lotus design top arms by Quinton Hazell and TR3 steering arms. Springing by combined coilspring damper units reacting through a single attachment point at each end. (Dampers by Armstrong, spring rates 110lbs.)
Proprietary 'live' rear axle located by twin parallel trailing arms and a diagonal member to provide lateral location. Springing by combined coilspring damper units. (Dampers by Armstrong, spring rates 75lbs.)
STANDARD ENGINES AND GEARBOXES:
Available late 1957 to mid 1960 and from October 1959 the model was known as the Lotus Seven "F" - 1172cc. FORD 100E side-valve engine developing variously between 28 and 40bhp at 4,500rpm depending on state of tune. Single downdraught Solex or twin SU H2 carburettors, sometimes with 4-branch exhaust manifold. Compression ratio 7.0:1 to 8.5:1. Matching 3-speed gearbox with Lotus remote gear change and Ford 100E gearknob. Standard ratios 3.664:1, 2.007:1, 1:1, Reverse 4.79:1 Close ratio (Buckler "C" Type gears?) 2.34:1, 1.33:1, 1:1.
Available December 1958 to mid 1960(?) model known as the "Super Seven" and also from October 1959 as the Lotus Seven "C" - 1100cc. COVENTRY CLIMAX FWA single overhead camshaft engine in Stage 1 tune developing 75bhp at 6,250rpm. 4-branch exhaust manifold, twin SU carburettors and competition electrics. Lightweight 4-speed BMC "A" Series gearbox and gearknob. Standard ratios 4.08:1, 2.58:1, 1.66:1, 1:1. Close ratios also available at extra cost.
Available October 1959 to mid 1960 model known as the Lotus Seven "A" (home market) and from January 1960 the Lotus Seven "America" (U.S. market) - 948cc. BMC "A" SERIES overhead valve engine in two forms - For the home market, Austin A35 with one SU H2 carburettor developing 37bhp at 4,800rpm. Compression ratio 8.9:1. For the US market ("America" model), Austin Healey Sprite (Mk. 1 Frog-eye) with twin SU H1 carburettors on special manifold developing 43bhp at 5,200rpm. Matching (smooth-case) 4-speed gearbox and gearknob. Standard ratios 4.08:1, 2.58:1, 1.16:1, 1:1 Reverse 5.17:1. Close ratios also available at extra cost.
By Hardy Spicer.
From Nash Metropolitan. (BMC type similar to Austin Healey "Frog-eye" Sprite but with bigger drum brakes.) Standard ratios - 4.875:1 pre-October 1959, 4.55:1 Super Seven and Seven "C" and 4.22:1 from October 1959. Other ratios available - 5.75:1, 5.125:1, 3.89:1, 3.73:1.
Hydraulic operated two leading shoe drum brakes by Girling. Cast iron drums 8" dia x 1 1/2" to front and rear.
FRONT: Pre July 1959 had 8" diameter Triumph Mayflower cast iron front drums drilled to BMC PCD with backplates welded onto cut down BMC backplates. Later models used complete 8" drum brakes from the Triumph Herald and TR wheels.
REAR: 8" dia x 1 1/2" cast iron drums which were standard equipment on Nash Metropolitan axles.
HANDBRAKE: Mechanical handbrake via horizontal lever.
Very early cars (first 25 of 100E production) had Burman type "worm & nut" steering gear. Later cars (circa March 1958 onwards) had a cut down Morris 1000 rack & pinion setup. Circa October 1959 early LHD Triumph Herald racks were used in upside down position. Column was universal jointed and steering wheel was 16" with two spokes in grey plastic by Wilmot Breedon. The Super Seven had adjustable column and 3-spoke aluminium/leather covered steering wheel.
WHEELS & TYRES:
Usually 15" x 4" diameter lightweight bolt-on steel rims with 520 x 15 (crossply) tyres:
Early cars used wheels manufactured by Rubery Owen (as used on the Turner sports car) with BMC stud centres (PCD) to suit both axles. Later, circa 1960, TR3 wheels were used with special adaptor plate at rear for Standard Triumph stud centres (PCD) all round. Lotus Super Seven/Lotus "C" were specified with 15" (x 4" x 48 spoke as on Climax engine Elite) knock-on wire wheels which were also available at extra cost on all cars. Provision for mounting spare wheel on rear panel. Spare wheel optional extra on home market cars.
GENERAL: Special lightweight (24lb.) 12 volt 31 amp-hour battery located next to the fuel tank in the tail. Coil and distributor, centrifugal advance and retard, belt driven dynamo, automatic voltage control. Fuse box mounted on dash panel (behind dash on later cars.
LIGHTING & HORN: Lucas L516 side lamps, SLR 576 fog lamp, SFT 576 driving lamp, L534 number plate light and Wingard 1055 combined rear and stop lights, Lucas HF1849 high frequency horn [as on the Frog-eye Sprite] and instrument lighting.
SWITCHES: Horn Button/Dip Beam Lucas 31438 model HD78 Turn / Pull / Turn Light Switch Lucas 31126 & Lucas Key Ignition / Start.
MISCELLANEOUS: From January 1960, windscreen wiper motor from Elite model, themostatically controlled electric cooling fan and winking indicators on Lotus Seven "America" model (U.S. market).
Ford and BMC cars have 3" dia. 0 - 100mph A.C. Speedometer (Ford with combined revolution readings in the gears from late 1958) and 2" dia full face A.C. Oil Pressure Guage (mechanical type), Water Temperature Guage (capillary type) and Ammeter. 3" dia Smiths Chronometric 0 - 8,000rpm Tachometer at extra cost. Coventry Climax Super Seven and Lotus Seven "C" have Tachometer, Oil Pressure Guage, Water Temperature Guage, and Ammeter as above, but Speedometer at extra cost.
Aluminium by Williams and Pritchard held in place using two aircraft spec. bungy cords.
Early cars had red "Vyanide", later ones had red PVC covered dashboard, trim panels, facia seat squabs and back rest.
EX-WORKS PRICES (from factory ephemera):
10th October 1957 - Seven (Ford 100E powered) - £526.00
1st October 1958 - Seven (Ford 100E powered) - £551.00
1st October 1958 - Super Seven (Coventry Climax powered) - £892.00
9th December 1959 - Seven 'F' (Ford 100E powered) - £587.00
9th December 1959 - Seven 'A' (BMC "A" Series powered) - £611.00
9th December 1959 - Seven 'C' (Coventry Climax powered) - £843.00
(Offered October 1958 & December 1959): On all models: Hood & Sticks; Cockpit Tonneau Cover; Windscreen Wiper Kit; Spare Wheel c/w Tyre, Tube & Hub Cap; Wire Wheel Conversion, Spare Wire Wheel, Tyre & Tube; Dunlop Racing Tyres (4); SU Electric Fuel Pump; Adjustable Steering Column & Leather Covered Steering Wheel, Close Ratio Gears (fitted or unfitted). On Ford Type only: Twin SU's and 4-Branch Exhaust.
Wheelbase 7'- 4", Front Track 3'- 11", Rear Track 3'- 11" (3'- 10 1/2" October 1959), Overall Length 10'- 3" (11'- 0" October 1959 (Spare Wheel??)), Overall Width 4'- 5", Height to top of scuttle 27 1/2", Ground Clearance 5".
Pre-October 1959: Original 100E Ford model without spare wheel - 725lbs and Export 100E Ford model with spare wheel - 822lbs. October 1959: Ford 100E model - 918lbs and BMC "A" Series model - 896lbs.