LOTUS SEVEN REGISTER
the web site for the
~ The Lotus Seven
The Series -
The First 'All Ford' Seven.
If there is one
component of the Series Two Lotus Seven that has always been a real cause of
concern, it has to be the rear axle. The Series One was fitted with the BMC
axle from the Nash Metropolitan, the Anglo-American car of the mid-1950's,
which was similar to that used later in the Austin Healey Sprite. In the cost
cutting exercise that was to produce the Seven Series Two, John Standen and
Nobby Clark of Lotus, were offered a particularly attractive deal by the
Triumph Motor Company for supply of their obsolete axles from the Standard 10.
Whilst not as strong as the BMC items and without the range of ratios, they
were considered adequate for the then current Ford and BMC engines fitted in
on a Series One had been achieved using a pair of trailing arms connected at
each end of the casing with an additional diagonal member to allay lateral
movement. On the Series Two this was changed with the upper location as before
but the lower combining lateral support being achieved by an ‘A’ frame
pivoting rearwards and connecting to the underside of the differential housing
via bracketry fitted using the axle drain plug. This, as well as requiring no
welding to the casing, was also considered an improvement to the car's road
holding under heavy acceleration and braking on uneven surfaces.
Letter announcing that Caterham Car Sales are to have
this revised method of location added a further dimension to the weakness of
the axle by allowing the casing itself to carry 'twisting' stresses between
the upper (side) and lower (centre) location points. The upshot of this is
that, as well as half shafts breaking, the casing itself became rather less
than oil tight particularly when excessive power or sticky tyre rubber were
In 1960 the
Series Two was originally specified with either a 28-40bhp 1172cc. Ford
side-valve or a 37-43bhp 948cc. BMC o.h.v. engine with 13" x 3˝J steel wheels
shod with skinny 520 x 13 crossply tyres. By the end of Series Two production
a fairly normal top of the range factory supplied Seven had nearly three times
the power and wider 4˝J wheels with radial rubber fitted and the customised
cars maybe 120bhp and 5˝J or even more.
were to either change for a stronger axle with the added expense of having to
change the PCD of the front hubs as well, or by the addition of a
'Stegosaurus' strengthening plate along part or all of its length, or by
changing the location method to both upper and lower trailing arms to
eradicate the stress along the length of the axle.
Official factory photograph taken at Hethel.
FIRST ‘ALL FORD’
The first Series
Three Lotus Seven left the factory in September 1968. The main change from the
old Series Two was, as already mentioned, Ford’s 2255E crossflow engine in
1600cc or 1300cc form. In addition the relatively new ‘live’ rear axle from
Ford Escort Mexico was fitted which meant larger rear drum brakes. With many
Ford parts being a favourite in competitive events, this unit had advantages
of increased strength, a large variety of final drive ratios and even the
possibility of a limited slip differential. With the new axle, the PCD had to
be regularised so that all wheels were interchangeable. This was achieved with
new front hubs. With the Ford PCD came the availability of their wider 13” x
5J Ford wheels along with Dunlop 165 x 13 SP Sport HR rubber requiring the
need for wider rear wings. The wheels used were the stronger variety that
Lotus fitted on their Cortina and the 51 Formula Ford models. So whilst the
old Series Two had Ford engine and gearbox and Standard Triumph rear axle and
wheels, the new Series Three used Ford parts for all these items.
indicators had been fitted to the first Seven “America” model early in 1960
and on all Series Two Sevens for export since. For these cars the front
indicator lights were Lucas L1130 dual element side light / indicators with
white lenses which did not comply with UK regulations. For the home market
indicator lights for the Series Three were now fitted with amber lenses as
Up until now the
Lotus Seven had always been a very basic car with the emphasis on light weight
with no frills or pretence of luxury other than those needed by the driver,
but not by the passenger! Fuel refilling had previously been achieved via the
filler cap located inside the boot area which meant undoing the boot cover.
For the Series Three the filler cap was located outside the boot area on the
back panel of the car as it is with the Caterham today.
Caterham's Price List.
For the first
time on a Lotus Seven a rear exit exhaust system was fitted as standard
equipment on the Series Three. Sales literature stated that this was to meet
noise regulation requirements. The standard Ford cast iron manifold was used
on right hand drive cars, but in order to clear the steering column, a
fabricated four branch tubular steel version was needed on left hand drive
red of the dashboard, trim panels, seat squabs and backs were changed for
black in line with other Lotus products of the day. This included ‘knitted’
pattern leathercloth for the seating, black carpeting throughout, a 14”
diameter black pvc covered brushed aluminium steering wheel and black pvc
bonded steel trim panels and dashboard.
In line with
other manufacturers and Lotus products, the electrical ground was changed from
positive to negative. This would make the sourcing of electrical components
Caterham's Lotus Seven Brochure.
previous Sevens, with tachometers fitted, had speedometers in front of the
passenger, the new car had both these Smiths instruments in front of the
driver. In addition, because of the new external filler cap and the subsequent
bend in the filler pipe, dipping the tank to measure fuel levels was no longer
possible and an AC fuel gauge had to be included. With this extra instrument
and in order to keep all instruments within view of the driver, a Smiths
combined water temperature and oil pressure instrument was fitted. The Ammeter
was AC in similar style to the fuel gauge.
NO CHANGE TO THE
With all these
changes to the Seven (engine, rear axle, wheels, wings, indicators, interior,
etc.) the chassis remained the exactly the same in all respects except one. Up
until now there was a provision for a lower rear mounting for the cycle wings
which were an option on Series Two cars for most of their production period.
There was no option for cycle wings with the Series Three and these brackets
Chassis Company and The Universal Radiator Company (Unirads) had made nearly
all of the chassis frames for the Series Two. Towards the end of Series Two
production another maker, Arch Motors, ‘came on line’ and Unirads were
gradually dropped. Arch had been started in the late 1950’s by John Robinson
and Don Gadd, two motorcycle sidecar racers who had made there own race
frames. Whilst they did not make Seven frames until 1967, they were
responsible for, amongst others, Type 22 Formula Junior and Type 23 Sports
Racing cars for Lotus as early as 1962 as well as for many other companies.
They were early exponents of siff-bronze welding and after much persuasion
managed to convince Colin Chapman that this non-fusion method was the way to
go. Arch’s involvement with the Seven continues today, nearly forty years on.
The Luxury Cars
- The ‘S’ and The ‘SS’.
Lotus Seven by
Jeremy Coulter (1986/1995)
Preparation/Restoration/Maintenance by Tony Weale (1991)
Seven made by Lotus between 1957 and 1973