The Hillman Imp is a small economy car made by the Rootes Group and its successor Chrysler Europe from 1963 until 1976. Revealed on 3 May 1963, after much advance publicity, it was the first British mass-produced car with the engine block and cylinder head cast in aluminium.
Being a direct competitor to the BMC's Mini, it used a space-saving rear-engine, rear-wheel-drive layout to allow as much luggage and passenger capacity as possible in both the rear and the front of the car. It used a unique opening rear hatch to allow luggage to be put into the back seat rest.
It was the first mass-produced British car with the engine in the back and the first to use a diaphragm spring clutch. The baulk-ring synchromesh unit for the transaxle compensated for the speeds of gear and shaft before engagement, which the Mini had suffered from during its early production years.
It incorporated many design features which were uncommon in cars until the late 1970s, such as a folding rear bench seat, automatic choke and gauges for temperature, voltage and oil pressure.
This unorthodox small/light car was designed for the Rootes Group by Michael Parkes (who later became a Formula One driver) and Tim Fry. It was manufactured at the purpose-built Linwood plant in Scotland. Along with the Hillman marque was a series of variations including an estate car (Husky), a van and a coupé.
The Imp gained a reputation as a successful rally car when Rosemary Smith won the Tulip Rally in 1965. This led the Rootes Group to produce a special rally conversion of the Imp under both the Hillman and Singer marques known as the Imp Rallye. In 1966, after winning the Coupe des Dames, Smith was disqualified under a controversial ruling regarding the headlamps of her Imp. The Imp was also successful in touring car racing when Bill McGovern won the British Saloon Car Championship in 1970, 1971 and 1972.
It was considered by some[who?][weasel words] to be advanced for the time, with its various innovative features and technical advantages over other cars.[example needed] But reliability problems harmed its reputation, which led to the Rootes Group being taken over by Chrysler Europe in 1967. The Imp continued in production until 1976, selling just under half a million units in 13 years.
Known internally within the Rootes Groups as the APEX project, the Imp came about because of the fuel shortage caused by the Suez Crisis in 1956. Petrol was rationed in the UK, sales of heavy cars (which Rootes was known for) had dramatically slumped in sales, and there was a huge market for small economical cars with low fuel usage. The BMC's Mini had already taken advantage of this opportunity with production starting in 1959. Although the project officially began in 1955, the market for small cars was soon recognised and it was evident that the project would evolve into Rootes first small economical car. Seeing an opportunity, Mike Parkes and Tim Fry offered to design the car; "Well Mike Parkes and I were very good friends. So we went to the director of engineering B. B. Winter and said to him we could design you just the car we want. And he said: Alright get on with it then!". The early stages of development presented the 'The Slug' which had clear similarities to a bubble car. However, the Rootes design board were not satisfied with this approach, and ordered the design team to press forward. This then lead to the next stage of the slug, appearing more utilitarian with appropriate styling.
The Hillman Imp was officially announced on 2 May 1963 when HRH Duke of Edinburgh was invited to open the factory in Linwood. After the opening, he then drove a silver Imp to Glasgow Airport. One of the first Imps produced is currently on display at the Glasgow Museum of Transport. Another early example from 1963 is at the National Motor Museum, Beaulieu with the registration 1400 SC.
Before and after its announcement, the Imp garnered significant attention from the motoring press. In 1962 the Small Car & Mini Owner magazine published an article titled "Enter the AJAX!" making notability of the all-aluminium water-cooled rear engine. The same year, The Express published an article titled "It's the new 'baby'", calling it "the first baby car ever built by the Rootes Group". In June 1963, the Motor Sport magazine commented on the press' reaction to the Imp who strongly favoured the Imp in terms of its engine, gearbox and competitive price; at launch, the standard model cost £508 1s 3d, while the deluxe version was £532 4s 7d.
The name 'Imp' was originally the name of an engine produced by Ailsa Craig Ltd; a manufacturer of marine engines. In 1962 the company was acquired by Warsop Fram Group, and all of Ailsa Craig Ltd's assets were up for sale. The Warsop Fram Group traded the Imp name to the Rootes Group in exchange for a new Humber Super Snipe motor car. The namesake was to emphasize its small-size, and to help it sell as the obvious competitor for the Mini.
The water-cooled four cylinder power unit was based on the Coventry Climax FWMA fire pump engine featuring an all-aluminium alloy over-head cam, combined with a full-syncromesh aluminium transaxle. This combination was very advanced at the time. Sir Alec Issigonis, designer of the BMC's Mini, had recently described the fitting of syncromesh on all forward gears as "impossible". Besides the engine's unique design, it was canted at a 45° angle to keep the center of gravity low and optimise road-holding.
As reported in tests such as The Practical Car and Driver, rear-engined cars generally suffer from oversteer handling characteristics to some extent, and to counteract this as much as possible, the Imp has a semi-trailing arm independent rear suspension system. This relatively costly and sophisticated solution, atypical for small-car design at the time, was insisted upon by its designers after testing at length a Chevrolet Corvair with swing axles. To attain balanced handling, the Imp actually uses swing axle geometry at the front, but this initially led to too much understeer and the camber was later reduced by lowering the pivot points.
Gradually increasing in popularity in the UK, Mark I sales in 1963 estimated 33,000 and increased to 50,142 in 1964.
However the Imp had decreased in sales in 1965 to 42,663. Reliability problems, mainly due to poor cooling of the rear engine, had soon surfaced, and the public image of the car was becoming negative. This was extremely worrying for the Rootes Group who were trying to compete with the Mini when its production had already totalled 1,190,000 during the 1960s.
The Mark I was introduced as a 2-door saloon and appeared in two models; the Basic and De Luxe. In October 1964, a luxury edition was introduced known as the Singer Chamois.
From the initial problems that surrounded the Mark I, the Rootes Group envisioned to re-introduce the Imp with significant changes both mechanically and cosmetically.
The Mk I Imps had a pneumatic throttle linkage and an 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 several trim and detail changes. Although the car was constantly improved over its production life, there was no single change as significant as that in 1965. Among these changes were an added water pump, cylinder head with larger ports and valves, along with 'Mark II' emblems appearing on the side of the doors.
The Imp was never officially badged nor referred to as the 'Mark III'. However, changes were made to the Imp range when the Rootes Group was fully acquired by Chrysler Europe and thus is sometimes referred to as the 'Chrysler Imp'.
After Rootes Group's acquisition from Chrysler in 1968, the entire range was revised except the Stiletto. The instrument panel and steering wheel were redesigned. The large speedometer previously positioned behind the steering wheel was replaced by a horizontal row of four circular dials/displays of varying detail and complexity according to the model specified. The right-hand dial, the speedometer, was now to one side of the driver's normal sightline, while one multi-functional stalk on the right side of the steering column replaced the two control stalks that had been directly behind the steering wheel, one on each side. The earlier Imp had been praised for the good ergonomic quality of its dash-board/fascia, and its replacement reflected similar trends in other new and modified UK vehicles at a time of "production rationalization". On the Imp, the more modern arrangement was seen by some as a missed opportunity.
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