When BMW resurrects the 6-Series name next year, they’ll be bringing back a model which left an indelible positive feeling for the brand on both sides of the Atlantic in the 70s and 80s.

The early versions of the big coupes were produced by Karmann for BMW in 1976, and 13 years later the series was killed off after more than 86,000 units had been produced.

The 6-Series was built on a lengthened 5-Series chassis, and was powered by variants of the M30 BMW straight-6 engine. The primary market for the car was the US, where the first 630CS with a 3-litre engine had a power output of 176bhp and sold with few changes until 1979 when a 3.2-litre 633CSi was produced, with Bosch L-Jetronic fuel injection.

That same year, the 628CSi, with a smaller engine, was produced for Europe, in a somewhat cheaper specification for the market. But because of US emissions and safety regulations (bigger bumpers made the cars heavier, for instance), the European cars had higher power outputs and better performance than their American cousins.

Early cars had 4-speed manual gearboxes, and later a 5-speed overdrive unit was available.

In mid-82, the Bosch Motronic engine management system was installed, improving performance, reliability and particularly efficiency.

1985 635 CSi owned by John G Burns (see below)

A restyling in 1983 also brought a better front suspension, and two years later the car got a larger capacity 3.4-litre engine along with ABS. Foglamps incorporated into the airdam were introduced in 1984 or so, and in 1986, the 6 got automatic transmission with ‘shift control’, along with electric power seats and - very important - a rear sunshade!

Up to this, the fact that it was a beautiful BMW big coupe had been enough for most buyers, but in 1987 the company decided there should be something special for the real petrolheads. The M6, with a 24-valve head on a 3.5-litre set of pots, outputted a hefty-for-the time 256bhp. A special sport suspension, and a close-ratio 5-speed manual gearbox, were included along with a limited-slip diff and larger wheels.

A rear self-levelling suspension was made available in the same year as an option.

M6 Highline

At the same time a plush ‘Highline’ version (above) was produced (called L6 in the US market) with the 182bhp 3.4 engine. The car had full leather trimming, even on the dashboard.

In 1988, the 635 was given the M30 engine variant from the 735, which added another 26bhp. The 7-Series donated its power steering the following year, and the standard transmission became a 4-speed auto with electric overdrive, while a 5-speed manual was available at no extra cost.

The last 6-Series was built in February 1989. It included a CD changer, something very forward for the time.

A number of turbocharged Alpina versions (below) of the 6-Series were also produced, but that’s another story.

The revived-name 6-series is expected next year, powered by 3.5- and 4.5-litre engines.

NOTE: my sources for this short history of the 6-Series included John G Burns’s excellent BMW home page as well as a number of US-sourced memoirs. Some discrepencies are due to differing specifications recorded for versions of the 6-Series produced for the quite different US and European markets, as well as the US system of designating new models by the following calendar year. BB