The idea sounds absurd: diesel-powered Ford Thunderbirds roam the streets of Munich under BMW supervision. But sometime in the 1970s, this unlikely premise apparently became a reality. Even more unlikely, the responsible party is none other than BMW Motorsport – perhaps the last organization you would associate with diesel power. Depending on how you look at it, the series of unlikely pairings all had eccentricities of size or markings of a flop. But either way, it’s an origin story that explains how a BMW diesel engine found its way into an American luxury coupe.
An American in Munich
You may not know the name Burkhard Goeschal. But it is at least one of the reasons why a fleet of Ford Thunderbirds landed over Munich sometime in the 1970s. According to him, Ford commissioned BMW Motorsport to “test and validate diesel engines from Steyr”. Logically, this meant that BMW Motorsport had to install diesel engines in vehicles with a Ford badge. Apparently Motorsport was financially unable to turn down the request – although seemingly far from what the Motorsport department does best. The agreement resulted in a bevy of Ford Thunderbirds showing up in Munich as test cars.
But they probably weren’t the wild and winged Thunderbirds of the 1950s and 1960s that roamed the streets of Munich. Remember that Goeschal only started at BMW in January 1978. This means that the Ford Thunderbird is at least in its seventh generation. Unlike previous models, the seventh-generation Thunderbird was smaller and placed a strong emphasis on fuel efficiency. Of course, these features were pure byproducts of the ongoing oil crisis. However, the test cars were almost certainly early or even pre-production ninth-generation models, and for a very good, seemingly unrelated reason: the Lincoln Mark VII.
The Thunderbird Diesel: Where It Ended
The Lincoln Mark VII debuted in 1983 as the Lincoln Continental Mark VII. The Mark VII was only available with two engines: a 5.0-liter V8 with up to 225 horsepower and a BMW M21 diesel engine. The Mark VII was based on the same Ford Fox platform as the contemporary Mustang, Mercury Cougar and yes – the ninth generation Ford Thunderbird. While the Ford Thunderbird never had a diesel engine, around 2,300 Lincoln Mark VIIs were delivered with diesel engines. With BMW power and a ZF-sourced automatic – instead of the four-speed Ford transmission that backs up the 5.0-liter – it’s almost certain that the Thunderbirds in Munich later became the Lincoln Mark VII.
Furthermore, it also makes sense to call the M21 a “Steyr diesel”. In the 1970s, BMW set out to develop an engine that combined strong performance with improved fuel economy. As you may have guessed, another direct response to the oil crisis. Development officially began in 1975, when a team of BMW engineers used the M20 gasoline engine as a basis. When the engine went into production, the designation M21 was decided. Right from the start, BMW intended the Steyr engine plant to be the exclusive production site for the new diesel. The plant was founded in 1978 as a joint venture with Steyr-Daimler-Puch before BMW took full control in February 1982. Early production in Steyr initially focused on six-cylinder gasoline engines, but diesel production was ramped up soon afterwards.
The BMW-Ford diesel cycle is closing
In 1983, Ford announced plans to purchase up to 190,000 BMW turbodiesel engines over several years. However, the rapid collapse of the American diesel market in the early 1980s limited these ambitions. 40 years later, only the Lincoln Mark VII can be seen. Many thanks to Steve Saxty for citing Dr. Goeschal. Although you won’t find this story in his excellent BMW books, we still recommend getting a set.
