20 May 2009

1957-1972 Lotus Seven

Aside from the Shelby Cobra, there is perhaps no other car more aped by kit and replica manufacturers than the simple Lotus Seven. More than 150 companies have tried their hand at Seven replicas -- some more ably than others -- and it is a testament to the special driving characteristics inherent in these little British roadsters that even today, more than 50 years after production of the first Series 1 car, they are still recognized as one of the best-driving machines on the road.

The automotive world has Colin Chapman to thank for the Lotus marque. Chapman was both an engineer and a tinkerer -- a useful combination for someone interested in building cars. In the early 1950s, he gained a reputation as a man capable of constructing winning race cars, and lessons learned from his day job at British Aluminum translated easily into what would become his pursuit of "adding lightness" to his little racers.

Chapman earned a devoted following through his advanced Mark VI sports racer, and by 1957 had been approached by a regular customer to design and build a road-going car capable of success in hillclimbs and track events as well.

The result was the Lotus Seven, a cycle-fendered open two-seater powered by an 1,172-cc Ford 100E 4-cylinder with a deDion rear suspension and 4.5:1 final drive. The engine was capable of anywhere from 28 to 40 hp, depending on compression ratio and carburetion; a single downdraft Solex carb was standard, though twin SUs could be fitted. A Ford 3-speed manual transmission with Lotus gear change mechanisms put power to the rear wheels, which were bolted to live rear axles borrowed from the Nash Metropolitan.

The Seven evolved over four series, and would include several powerplants, ranging from mundane to spectacular, including the rare Twin-Cam SS of 1969, with just 13 built. But all Sevens shared the same basic philosophy that would characterize every subsequent Lotus, from road cars to World Championship-winning Formula One machines: light weight and simplicity.

Unstressed, unadorned aluminum body panels were stretched over a lightweight steel space frame, and early cars weighed as little as 725 pounds. Many were delivered unpainted, and polished-aluminum Sevens are not uncommon. Front suspension was independent, courtesy of transverse wishbones with an anti-roll bar and MacPherson struts, while the solid rear axle used twin parallel trailing arms and a diagonal link. Common to all Sevens were rudimentary accommodations and a lack of refinement, with no apologies. Creature comforts were non-existent and weather-proofing was more a rumor than a reality, with side curtains and tops optional.

With a wheelbase of just 88 inches, the entire package resulted in a road car teetering on the edge of go-kartishness. Acceleration was brisk at worst and stunning at best, depending upon the powerplant, and rarely has a car been so nimble.

Differences among the Series 1 through Series 4 cars deal mostly with the engines powering them. Dozens of motors would make their way into the cars over the years, from 998-cc, 43-hp units from the Austin-Healey Bugeye Sprite to 1,600-cc Cosworth racing engines tuned for more than 125 hp.

In all, about 3,000 Sevens were built between 1957 and 1972, before Caterham Cars acquired the rights to produce them, which it does to this day.

Colin Chapman changed the face of performance car manufacturing with his humble little Seven. By placing the emphasis on small displacement and simple, lightweight chassis, he pioneered the "less is more" philosophy that would revolutionize the racing business throughout the 1960s, and which would see his own F1 teams win several World Championships.

All by adding lightness.

1 Reader Comment

  • 1
    Sean Hoover United States June 10, 2013 at 15:30
    I have a 65 super 7 S2. I just rebuilt the engine, transmission, rear end, gearbox, etc.... i am looking to get the carbs rebuilt and a new hood made. The story of rebuilding the car with your father reminded me of my son and myself. Why cant i find a value estimate of a 65 s7 s2 on the site?

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