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Hillman Imp
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The Hillman Imp is a compact, rear-engined saloon car that was manufactured under the Hillman marque by the Rootes Group (later Chrysler Europe) from 1963 to 1976. An estate version known as the Hillman Husky was produced from 1967.
History
Known internally within Rootes as the "Apex", the Imp was intended as a rival to the Mini.
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Encyclopedia
The Hillman Imp is a compact, rear-engined saloon car that was manufactured under the Hillman marque by the Rootes Group (later Chrysler Europe) from 1963 to 1976. An estate version known as the Hillman Husky was produced from 1967.
History
Known internally within Rootes as the "Apex", the Imp was intended as a rival to the Mini. A key difference between the two cars was the Imp's 875 cc all-aluminium power unit, adapted by Rootes from a Coventry Climax fire pump engine which had enjoyed some success on the racing scene (ironically Coventry Climax were later to become a subsidiary of British Leyland - a Rootes rival). The Imp used a derivative of the Climax FWMA engine whereas Lotus and others used an FWMC engine with many detail changes and an entirely different cylinder head. This was mounted behind the rear wheels, slanted over at 45° to fit. Partly to counteract the oversteer handling characteristics of a rear engined design, the Imp had a semi-trailing arm independent rear suspension system - quite sophisticated for a small car at the time. Front suspension was by swinging arms. Over the life of the car, Rootes (and then Chrysler) produced three basic body styles. The original Saloon was introduced in 1963 with an opening rear hatch and ran through to the end of production in 1976. A coupe was introduced in 1965 that had a non-opening rear window that was more steeply raked than the saloon hatch, and a roofline lower. In 1965 the Van was introduced and the same pressings were used to create the estate, badged as a Husky in 1967. Both vehicles were retired in 1970. Through the use of the opening rear window on saloon models, the car was effectively a hatchback. In true Rootes (and British) tradition, there were also some badge-engineered derivatives, such as the luxury Singer Chamois, and the Sunbeam Sport with a more powerful twin-carburettor engine. The coupe bodyshell was used to create the Imp Californian and Sunbeam Stiletto variants.
The Imp was a massive and expensive leap of faith for Rootes. Not only did it not have any real experience in building small cars or indeed wholly aluminium engines, it was forced to build a new assembly plant on the outskirts of Glasgow, in the town of Linwood in which to assemble the Imp, since planning regulations banned it from further expanding its Ryton plant near Coventry. Government pressure (and grant money), was applied to bring jobs (approx 6000) to this unemployment blackspot. (Such government action was common in the 1960s - the most notorious being the forced merger of the companies that became British Leyland by Minister of Technology, Tony Benn). The investment also included an advanced die-casting plant to manufacture the aluminium engine casings, and a stake in the Pressed Steel Company which manufactured body panels. The problem was that Linwood was over away from Ryton, and the engine castings although made in Linwood, would have to be sent to Ryton to be machined and assembled, and then sent back up to be put on the cars - a round trip.
The Glaswegian workforce who were all recruited from the shipbuilding industry were also not versed in the intricacies of motor vehicle assembly, and Imp build quality and reliability suffered. They also brought with them their militant left-wing values, and as a result strike action and industrial disputes were a rule rather than an exception. In 1964 there were 31 stoppages and only a third of the plant capacity was realised - 50,000 rather than 150,000. On the other hand the Imp was seen as a "Scottish car" and was popular north of the border.
The daring design of the Imp was also somewhat underdeveloped, and mechanical problems were common in the early cars. In 1966 a major revision of the Imp was released, effectively splitting the marque into Mk I and Mk II cars. The Mk I Imps had a pneumatic throttle linkage and automatic choke, both of which were replaced by more conventional items on the Mk II. The Mk II also had improved front suspension geometry and a host of trim and detail changes. Although the car was constantly improved over its life there was no single change as big as that in 1966. Despite the initial problems, the car itself was relatively popular, thanks to its competitive price, distinctive styling and cheap running costs. It was though, overshadowed in popularity by the Austin Mini in the 1960s: rumors arose during the 1960s and have subsequently persisted that poor understanding of cost accounting by BMC management caused the basic Mini to be sold at a loss: resulting underpricing of the Mini could have damaged sales of the Imp. Budgeted production volumes and time-lines are never more than a best estimate, and differences of opinion concerning the 'correct' imputation of actual fixed costs, including amortization of the massive capital investment needed in production capacity, make it unlikely that proof can ever be adduced either way concerning the profitability of individual mass produced models such as the Mini and the Imp.
The huge investment in both the Imp and the Linwood production plant proved to be the undoing of Rootes, and its commercial failure led to huge losses to the Coventry-based firm. By 1967 the company had fallen into the hands of Chrysler, to become part of Chrysler Europe, whose stewardship led to the death of the Imp in 1976, after fewer than 500,000 were built and the entire empire collapsed two years later, when it became part of Peugeot.
The Ryton assembly plant continued in operation until 2006 manufacturing Peugeot models. The Linwood plant was closed in 1981.
Production
Approximately half a million, 50% of those in the first 3 years of production.
The Imp used a derivative of the Climax FWMA engine whereas the Lotus cars used a
FWMC engine which had an entirely different cylinder head.
Export
Unassembled cars were exported for assembly in Ireland, New Zealand, Portugal, Venezuela, Uruguay, Costa Rica, South Africa & Australia.
Imp variants
- Hillman Imp
- Hillman Imp Mark I
- Hillman Imp de Luxe Mark I & Mark II
- Hillman Imp Super
- Hillman Imp GT (Australian model)
- Hillman Californian (coupé / fastback saloon version)
- Hillman Husky (estate version of the Imp)
- Commer Imp Van
- Hillman Imp Van
- Singer Chamois Mark I, Mark II, Sport, & Coupé (upmarket, luxury versions of the Imp)
- Sunbeam Imp Sport
- Sunbeam Sport
- Sunbeam Chamois & Chamois Coupé (luxury version of the Imp)
- Sunbeam Stiletto
- Sunbeam Californian
- Sunbeam Imp Basic (North America)
- Sunbeam Imp De Luxe Mark I & Mark II (North America)
Cars using Imp mechanicals
Imps in motorsport
The Imp enjoyed modest success in both club and international rallying. Rootes introduced a homologation special called the Rally Imp in 1964. The Rally Imp featured many modifications over the standard model, the most important of which was an engine enlarged to 998 cc. Notable successes for this model include the 1965 Tulip Rally in which the works Imps of Rosemary Smith and "Tiny" Lewis finished first and second overall.
Imps were also successful racing cars. The privateer team of George Bevan dominated the British Saloon Car Championship (later known as the British Touring Car Championship) in the early 1970s. Driven by Bill McGovern, the Bevan Sunbeam Imp won the championship in 1970, 1971 and 1972 with limited factory support.
In UK club racing the Imp variants became highly successful in the under 1000cc Special Saloon category,
Notable exponents of the Imp in racing include Ian Forrest, Harry Simpson, Ricky Gauld, John Homewood, Roger Nathan, Gerry Birrell, Ray Payne, Chris Barter and many others.
998 cc Imp engines were also used in 3 wheeled racing sidecars in the 1970s and 1980's. Exhaust systems were naturally constructed on a one off basis, and often sporting the Twin Weber twin choke set up. A number of sidecar crews raced Imp engined outfits at the Isle of Man TT races, best placement being Roy Hanks in eleventh place in the 1976 TT 1000 cc Sidecar.
The engine proved flexible and very easy to tune. The overhead camshaft design meant that the head could be flowed and ported to allow the engine to run at high speeds. Useful improvements in power could be gained by replacing the standard silencer with one that impeded the exhaust gas flow less and with better carburettors. However, in adapting the design to suit modern mass production methods, Rootes had left the engine somewhat more fragile than its Coventry Climax parent, hence any serious tuning must inevitably be accompanied by reliability modifications such as replacing the cylinder head gasket with gas-filled Wills rings.
External links
Bibliography
- Mowat-Brown, George: Hillman Imp: The Complete Story; The Crowood Press Ltd (24 Nov 2003); # ISBN-10: 1861266197 : # ISBN-13: 978-1861266194
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