Editing Lotus Seven (section)

==History==
==={{anchor|S1|Series I|Series 1}}Series 1===
{{Infobox automobile
| name = First generation
| production = 1957–1960
| engine = {{convert|1172|cc|L|1|abbr=on}} [[Straight-four engine|I4]]
| image = 1959 Lotus Super Seven Series 1 (15623495517).jpg
| related = [[Lotus Eleven]]
| caption = 1959 Lotus Seven
}}

The Lotus Seven was launched in 1957 to replace the Mark VI as the entry-level Lotus model. The Seven name was left over from a model that Lotus abandoned, which would have been a [[Riley Motor|Riley-engine]] single-seater that Lotus intended to enter into the [[Formula Two]] in 1952 or 1953. However, the car was completed on Chapman's chassis as a sports car by its backers and christened the Clairmonte Special.

Externally similar to Chapman's earlier [[Lotus Mark VI]], but with a different tubular frame similar to the [[Lotus Eleven]], the Seven was powered by a {{convert|36|bhp|kW PS|0|abbr=on}} [[Ford Sidevalve engine|Ford Sidevalve]] 1,172 cc [[straight-four engine]]. In addition to the Ford unit, both [[BMC A-Series engine|BMC series A]] and [[Coventry Climax]] FWA engines were available for fitment. Under the [[Purchase Tax]] system of the time cars supplied as a kit did not attract the tax surcharge that would apply if sold in assembled form. Tax rules specified assembly instructions could not be included. This situation remained until 1973 and a large proportion of Sevens sold in the United Kingdom were delivered in kit form as a result.

The Seven Series 1 was used both on the road and for club racing (750 motor club in the UK).

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==={{anchor|S2|Series II|Series 2}}Series 2===
{{Infobox automobile
| name = Second generation
| production = 1960–1968
| engine = {{convert|1340|cc|L|1|abbr=on}} [[Straight-four engine|I4]]
| image = 1965 Lotus Seven S2.jpg
| caption = 1965 Lotus Seven
}}
The Lotus Seven S2 followed in June 1960 and was supplemented by the Lotus Super Seven S2 from 1961.<ref name=Sedgwick>Michael Sedgwick & Mark Gillies, A-Z of Cars 1945–1970, page 117</ref> These were slightly more road-oriented than the Series 1, and received a somewhat simpler chassis. The Series 1's aluminium nosecone was changed to a fibreglass unit. Cycle fenders were originally standard, with clamshell units standard fitment on the 1500, Super Seven, and America or available as an option.<ref name=7regS2>{{cite web | url = http://www.lotus7register.co.uk/ser2page.htm | archive-url = https://web.archive.org/web/20191219121338/http://www.lotus7register.co.uk/ser2page.htm | archive-date = 2019-12-19 | title = Series Two Page: Original Specifications | work = Lotus Seven Register }}</ref>

While the 1172&nbsp;cc Sidevalve unit remained available until 1962, the series 2 typically used [[Ford Kent engine]]s of 1,340 or 1,499&nbsp;cc from the [[Ford Consul Classic]]. These were also available with [[Cosworth]] modifications; the Cosworth 1,340 cc "Super Seven" delivered {{convert|85|bhp|kW PS|0|abbr=on}} and the later "Super Seven 1500" {{convert|105|bhp|kW PS|0|abbr=on}}.<ref name=Sedgwick /> Some Series 2 Sevens built during 1968 (oftentimes referred to as "Series {{fraction|2|1|2}}") were fitted with the later [[Ford Kent engine|crossflow Kent engine]] of 1,599 cc.<ref name=7regS2/>

The series II had problems with its [[Standard Motor Company|Standard]] Companion [[station wagon|estate car]] rear axle and differential, unable to cope with the high power and cornering forces of the Seven. This was later solved on the Series III by installing a [[Ford Cortina]] rear end. Production of the Series 2 ended in August 1968, after 1310 examples had been built.<ref name=7regS2/>

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==={{anchor|S3|Series III|Series 3}}Series 3===
{{Infobox automobile
| name = Third generation
| production = 1968–1970
| image = 1969 Lotus Seven S3 1.6 Front.jpg
| engine = {{convert|1600|cc|L|1|abbr=on}} [[Straight-four engine|I4]]
| caption = 1969 Lotus Super Seven Twin Cam SS
}}
The Seven S3 was released in 1968.<ref name=Sedgwick /> As for late Series 2s, the S3 typically received the 1,599&nbsp;cc [[Ford Kent engine|crossflow Kent engine]]. First shown at Earl's Court in 1969, the Super Seven Twin Cam SS used the [[Lotus-Ford Twin Cam|Lotus Twin Cam engine]]. Only 13 examples were built. While only manufactured by Lotus for around two years, the Series 3 was the model later revived by Caterham after they ran out of Series 4 kits some time in the first half of the 1970s. In modified form, the design continues to be produced until today (2023).

[[File:Lotus Super Seven 1970 A2.jpg|thumb|left|1970 Lotus Super 7]]
Between 1970 and 1975, following a representation agreement, Lotus Argentina SA obtained the licence to manufacture the Lotus Seven in Argentina. This production reached approximately 51 units. These vehicles were not replicas but built under licence and branded as Lotuses.<ref>{{cite web | url = http://www.lotus7register.co.uk/salot7.htm | archiveurl = https://web.archive.org/web/20200625025506/http://www.lotus7register.co.uk/index.htm | archivedate = 2020-06-25 | title = The South American Lotus Seven | work = Lotus Seven Register | date = 2000-06-18 | first = John W. | last = Watson }}</ref><ref>{{cite web | url = http://www.automovilsport.com/historia/LotusArgentino/nota.html | work = Automovil Sport | title = Seven | trans-title = The story of the Lotus Sevens manufactured in Argentina | first = Richard | last = Vignoles | language = es }}</ref>

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==={{anchor|S4|Series IV|Series 4}}Series 4===
{{Infobox automobile
| name           = Fourth generation
| production     = 1970–August 1973
| image          = Lotus7-S4.jpg
| engine         = {{ubl
  | 1298&nbsp;cc ''[[Ford Kent engine|Ford Kent]]'' [[Overhead valve engine|OHV]] [[Straight-four engine|I4]]
  | 1558&nbsp;cc ''[[Lotus-Ford Twin Cam|Lotus Twin Cam]]'' [[DOHC]] I4
  | 1599&nbsp;cc ''[[Ford Kent engine|Ford Kent]]'' OHV I4
  }}
}}
In 1970, Lotus radically changed the shape of the car to create the slightly more conventional sized Series 4 (S4), with a squarer fibreglass shell replacing most of the aluminium bodywork. It also offered some luxuries as standard, such as an internal heater matrix. The S4 Seven could be supplied with 1298 or 1599 cc [[Ford Kent engine|Kent engines]] or the [[Lotus-Ford Twin Cam|twin cam]].

Until now, most Sevens in the UK had been sold in kit form in order to avoid paying [[purchase tax]]. However, once the UK joined the [[EEC]] on 1 January 1973, the [[VAT]] system was adopted instead so the tax advantage of the kit-built Lotus Seven came to an end. Accordingly, in 1973, Lotus decided to shed fully its "British tax system"-inspired [[kit car]] image. As part of this plan, it sold the rights to the Seven to its only remaining agents [[Caterham Cars]] in England and [[Steelbro|Steel Brothers Limited]] in New Zealand.

Caterham ran out of the Lotus Series 4 kits in the early 1970s. When this occurred and in accordance with their agreement with Lotus, Caterham introduced its own brand version of the Series 3. They have been manufacturing the car ever since as the [[Caterham Seven]]. Steel Brothers Limited in [[Christchurch]], New Zealand, assembled Lotus Seven Series 4s until March 1979 when the last of the 95 kits provided by Lotus was used up.<ref>Steelbro innovations keep it in front of the competition, The Press, Christchurch, 14 September 2007, Fairfax Media</ref><ref>New Zealand Classic Car magazine, Volume 22 Issue 2, page 67, ISSN 1170-9332</ref> Steel Brothers had a much wider range of factory options than the UK models with carpet, centre console glove-box, radio, window-washer and hardtop. Sold largely to competition enthusiasts, the NZ cars also had engine modifications, close-ratio gears, and adjustable suspension as factory options. As such, they were very successful in local racing. With officially licensed production stopping in 1979, the last Lotus badged Seven, a Series 4, was therefore produced in New Zealand.<ref>{{cite magazine | url = http://www.clublotus.org.nz/Edition%2057.pdf | archive-url = https://web.archive.org/web/20181221214740/http://www.clublotus.org.nz/Edition%2057.pdf | archive-date = 2018-12-21 | title = The last Lotus 7 | page = 12 | publisher = Club Lotus NZ Inc. | first = Rex | last = Oddy | number = 57 | magazine = Edition }}</ref>

Steel Brothers Limited attempted to make a wider, modernised version of the Series 4, the Lotus Super 907, using the twin cam [[Lotus 907]] engine. In the spring of 1978 it was announced that this was to be sold in the United States<ref name=NZA>{{citation | ref = NZa | title = Assembly: New Zealand Car Production 1921–98 | last = Webster | first = Mark | publisher = Reed | year = 2002 | page = 146 | location = Birkenhead, Auckland, New Zealand | isbn = 0-7900-0846-7 }}</ref> - but the American importer had no funds and the project came to naught.<ref name=GGL>{{cite web | title = Super 907 | publisher = Golden Gate Lotus Club | work = Chapman Report Online | last = Rosner | first = Jon |date=June–July 2003 | url = http://gglotus.org/blog/2010/09/super-907/ | access-date = 2013-04-15 }}</ref> The single finished Super 907 was moved from New Zealand to the United States in 2010 to undergo a full restoration.<ref>{{Cite web|url=http://gglotus.org/blog/?p=1570|title = Super 907|date = 20 September 2010}}</ref>