Hillman Imp

Lore & Background

The Imp originated from the APEX project, prompted by the 1956 Suez Crisis fuel shortage. Designers Michael Parkes and Tim Fry offered to create a small economical car for Rootes. Early development produced 'The Slug', a bubble-car-like design, but the design board ordered a more utilitarian approach. Extensive road testing was carried out in Norway, East Africa, and Canada by a team led by Ken Sharpe.

The water-cooled four-cylinder engine was inspired by the Coventry Climax FWMA, featuring an all-aluminium alloy overhead camshaft and a full-synchromesh aluminium transaxle. The engine was canted at 45° to lower the centre of gravity. The Imp used semi-trailing arm independent rear suspension, a costly solution atypical for small cars, chosen after testing a Chevrolet Corvair. Front suspension used swing axle geometry, initially causing understeer, later corrected by lowering pivot points.

The Imp suffered from reliability problems, particularly poor cooling of the rear engine, which harmed its reputation and contributed to the Rootes Group being taken over by Chrysler Europe in 1967. Production continued until March 1976.

Reader's Guide

The Hillman Imp's significance lies in its advanced engineering for a small economy car: an all-aluminium engine, overhead camshaft, and full-synchromesh gearbox were unusual for its class. Its rear-engine layout and sophisticated suspension aimed to balance handling, though early oversteer and understeer issues required adjustment. The Imp's rallying achievements, including a 1-2 finish at the 1965 Tulip Rally with Rosemary Smith and 'Tiny' Lewis, demonstrated its potential in competition. However, persistent reliability problems, especially engine cooling, damaged its public image and sales, which never matched the BMC Mini's success. The Imp's legacy is that of a technically ambitious but flawed vehicle; its production run of 13 years and nearly half a million units shows it found a market, but its reputation was ultimately undermined by the very issues that also led to Rootes' takeover. The later use of bored-out Imp engines in competition by tuners like Paul Emery and Andy Dawson indicates the powertrain's latent capability.

Did You Know?

• The Imp was the first British mass-produced car with an aluminium engine block and cylinder head.
• The name 'Imp' was traded to Rootes by Warsop Fram Group in exchange for a Humber Super Snipe.
• The Rally Imp used a 998 cc engine with wet-liners, not intended for road use.
• The Imp's engine was canted at a 45° angle to lower the centre of gravity.