Bristol 406 Zagato

The Bristol 406 Zagato is a British-Italian sports car based on the Bristol 406 Saloon, with a body designed and built by Zagato. It was commissioned by Bristol dealer Tony Crook and only a small number were built. It is lighter, smaller, and faster than the factory-bodied base car. Some older Bristol chassis later received similar Zagato bodies. Today, the 406 Zagato is considered one of the most desirable classic Bristols.

History Bristol Cars, the automotive division of the Bristol Aeroplane Company, was established after the end of World War II and began producing luxury cars based on BMW technology in 1946. The chassis and engines were derived from pre-war BMW Types 326, 327, and 328. These design plans were reportedly brought to Britain as reparations during the war, although others doubt this narrative.Balfour 2010, p. 48. Prior to the outbreak of WWII, HJ "Aldy" Aldington of the AFN company, builder of Frazer Nash cars, had secured both the sales rights for the six-cylinder range of BMWs for the UK, and the right for AFN to manufacture cars and components based on these designs in the UK. As the end of hostilities neared, AFN began to plan resuming civilian production of cars, while the Bristol Aeroplane Company examined the building of automobiles as a way to keep the company busy after their wartime contracts ended, and established Bristol Cars to that end. Shortly after the war, Aldy Aldington and his brother Don traveled to Germany, returning with a Mille Miglia 328 and blueprints for many of BMW's pre-war designs. In July 1945, Bristol Cars acquired AFN, and the BMW licenses were transferred to the new owner. The new company also benefited from the addition of former BMW engineer Fritz Fiedler. Bristol Cars began producing an English version of BMW's M328 straight-six, both to use in their own cars and to supply to Frazer Nash for their post-war models.

The debut 400 model, featuring bodywork based on a BMW coupé,Bristol's designer Dudley Hobbs based the design of the 400's body on a body that Peter Schimanowski had designed for the BMW 327 in 1938 and that the Darmstadt-based Autenrieth body plant had built. Cf. Classic Cars Special: English classic cars, p. 6 ff. was followed by the Touring-bodied 401, 402, and 403 models, which are treated as a single-model family in most literature. In 1953, the third generation of Bristol cars emerged, with the two-door 404, followed by the four-door 405 a year later. These models still retained BMW designs in their engineering. However, production levels in the mid-1950s were only about half of what they had been in the early years. During the autumn of 1958, Bristol introduced the fourth-generation model, the four-seat 406 Saloon. This model represented a departure from the brand's initial focus on sportiness. It was larger, heavier, and more luxurious than earlier Bristol's.N. N.: Bristol 406 with four-wheel disc brakes Sports Cars Illustrated, October 1958.Dieter Günther: Bristol Cream. Der Motor macht’s: Die Bristol-Modelle 406 und 407, In: Oldtimer Markt Sonderheft 14 („Gran Turismo: Die Großen Reisecoupés“), 1994, pp. 34. However, these changes resulted in a loss of the typical agility associated with Bristol cars, and despite having a larger engine, the 406 Saloon was slower than its predecessors.L. J. K. Setright: And now a quick look at Setright's Bristols. Car, January 1974. As a result, it was sometimes perceived as underpowered.

Bristol had plans to create a shorter and faster two-seater version of the 406 Saloon at their factory, with a prototype built in 1958, but full-scale production was abandoned due to cost considerations and uncertain prospects for the company.Balfour 2010, p. 250. The following spring, Tony Crook, a Bristol Cars board of directors member and the brand's largest dealer, revived the idea of a special sport model based on the 406. This led to the development of the 406 Zagato as an independent project by Anthony Crook Motors, rather than an official Bristol Cars model. The 406 Zagato was intended to return Bristol to its origins: according to Crook it was designed for drivers who were prepared to sacrifice comfort and space for the sake of sporting performance. In Crook's estimation, the key aspect was a light and compact body. He commissioned Italian Carrozzeria Zagato, known for its expertise in lightweight constructionDoug Blain: Automatic GT. Forecast for the Future? Bristol 407 GTZ Zagato in: Road & Track, February 1962. and whose British general importer Crook had been for years, to design and build it.Simon Taylor: Soul Survivors. Classic & Sports Car, Heft 8/2006, pp. 132 ff. (139) Additionally, Abarth was tasked with increasing the engine’s power.

The 406 Zagato prototype was unveiled exactly one year after the introduction of the 406 Saloon. It debuted at the Earls Motor Show in London from October 21–31, 1959. The prototype was displayed either on the Bristol Cars, Anthony Crook Motors,Till Schauen: High Fashion, British Classics, Heft 6/2014, pp. 89. or Zagato stand, depending on the source. Regular production began in the fall of 1959, ending a year later. Notably, the Bristol 406 was exclusively available through Anthony Crook Motors—other Bristol dealers could not access it.A.G. Pritchard: Bristol built – but air inspired. Sporting Motorist, October 1962.

The 406 Zagato did not achieve significant success. Of the production goal of ten vehicles, only six were produced, and even those proved difficult to sell. Despite its limited commercial success, this was the beginning of a longstanding collaboration between Bristol and Zagato: In 1960, a compact sports car with 406 technology and a hatchback body from Zagato (406S Zagato) was produced, followed in 1961 by a similarly designed car based on the Bristol 407, incorporating a V8 engine from Chrysler (407 GTZ Zagato). While these two models remained one-offs creations.Balfour 2010, p. 249. Bristol went on to sell a total of about 90 units of the 412 Targa coupe and its successor, the Beaufighter, whose body was designed by Giuseppe Mittino for Zagato, from 1975 to 1993.Rex Greenslade: Bristol Fashion. Road Test Bristol 412, Motor vom 5. March 1977.

Naming

The four-seater which in 1958 took over the role of Bristol Cars' main model, previously filled by the Bristol 405, is commonly known as the 406 Saloon.N. N.: Seventh of the Line, Autocar vom 29. August 1958. The lightweight special edition model with Italian bodywork was marketed as the 406 Zagato. In more recent literature, the designations 406 Z, 406 GTZ, or 406 GT Zagato (not used in 1959) are also sometimes found.

Features

Chassis and suspension The 406 Zagato is built on a steel box frame with longitudinal members and cross members, which shares the construction and dimensions with the regular 406 Saloon. The frame traces its basic features back to the chassis of the 1936 BMW 326. The front suspension is independent, with upper wishbones and a lower transverse leaf spring. At the rear, the car is equipped with a rigid axle featuring a Watt's linkage and a trailing arm, torsion bar springs with suspension levers, and self-designed shock absorbers.Zu den Einzelheiten s. Motor vom 6. November 1946Dieter Günther: Bristol Cream. Der Motor macht’s: Die Bristol-Modelle 406 und 407, In: Oldtimer Markt Sonderheft 14 („Gran Turismo: Die Großen Reisecoupés“), 1994, pp. 33. Additionally, the car decelerates with four Dunlop disc brakes.

Engine and transmission

All 406 Zagato models are powered by Bristol's inline six-cylinder petrol engine. The version used here, with a bore × stroke of , is a further development of the engine already installed in the 400, which goes back to the 1938 BMW M328 design. While the Bristol engine shares its key features with the BMW engine, Bristol's version is designed in inches rather than metric dimensions, and some materials are used differently.Till Schauen: High Fashion, British Classics, Heft 6/2014, S. 88. The engine has hemispherical combustion chambers, with two inclined overhead valves per cylinder. The intake valves are operated by a camshaft in the cylinder block via tappets, pushrods, and shaft-mounted rocker arms. Another set of pushrods goes across the cylinder head to a second rocker shaft to operate the exhaust valves.Zum Motor insgesamt: Dieter Günther: Man lebt nur zweimal. Modellgeschichte des Bristol 400 und des 401, in: Oldtimer Markt, Heft 9/1996, pp. 230. The fuel mixture is delivered by three 32 PBI/7 Solex downdraft carburetors.

In the 406 Zagato, the engine was available with two different power ratings:

Individual cars, including the prototype publicly exhibited in October 1959, are equipped with the basic Type 110 version of the engine, which was also fitted to all 406 Saloons.Martin Buckley: Bristol Fashion, Vorstellung und Fahrbericht des Bristol 406 Zagato, in: Classiccars 9/2001, pp. 105. It produces , with a torque of at 4700 revolutions per minute.Für die technischen Daten des Bristol 406 Saloon s. N. N.: Seventh of the Line, Autocar vom 29. August 1958. Most 406 Zagatos feature a more powerful Type 110S version of the six-cylinder engine, not offered in the 406 Saloon. It delivers a maximum output of with the same displacement. Maximum torque is slightly lower than in the base version at but at a lower rpm of 3750.Martin Buckley: Bristol Fashion. Vorstellung und Fahrbericht des Bristol 406 Zagato, in: Classiccars 9/2001, pp. 106. The increase in power was achieved by raising compression to 9.0:1,Balfour 2010, p. 248. and adding a modified camshaft and new exhaust system, including a manifold from Abarth.Till Schauen: High Fashion, British Classics, Heft 6/2014, pp. 87.

Engine power is transmitted to the rear axle via a four-speed manual transmission with overdrive, and a propeller shaft. The first gear of the Bristol-built transmission is not synchronized. The Laycock de Normanville overdrive, which has been standard on all Bristols since the 405, can be engaged in fourth gear and disengages automatically when downshifting.Christopher Balfour: Bristol Sixes – 400 to 406, in: Classic & Sports Car, Heft October 1990.

Bodywork The body of the 406 Zagato is independent. It has neither stylistic nor technical references to the body of the 406 Saloon designed by Dudley Hobbs and Dennis Sevier.

Design