Model Page

Hillman Imp

Hillman Imp

Production Run:


Production Date:

October 1963 – March 1976


875cc Four Cylinder All Aluminium


Linwood (Scotland)


25.4 Secs

Max Speed:

85 Mph

Released in late 1963 the Hillman Imp was manufactured by the Rootes Group bearing the Hillman marquee, developed under the project name “Apex” the vehicle was the first small car manufactured by the Rootes Group since the end of the Second World War. The Imp used an unconventional layout and featured a rear mounted 875cc lightweight all aluminium engine derived from the Coventry Climax powering the rear wheels. Rushed development and testing resulted in reliability issues that, coupled with the high build costs caused mounting losses for the Rootes Group that ultimately led to the takeover by Chrysler.

Rootes started investigating the possibility of launching a small car in 1955 at the time they only produced medium and large sized cars. Late 1956 brought the onset of petrol rationing thanks to the Suez crisis during this time sales of the sub 1 litre class of vehicles more than quadrupled by 1957 as vehicles with larger engines suffered badly as customers clambered for small, economical vehicles.

The initial investigations were headed up by Project Engineer Mike Parkes and Co-ordinating Engineer Tim Fry, carefully evaluating existing small, low cost vehicles already on the market such as the Citroen 2CV and Fiat 500 they defined that the vehicle should seat two adults and two children, comfortably exceed 60 mph and achieve around 60 mpg and the vehicle should be fun to drive. Considerable effort was taken to develop an aerodynamic vehicle to allow the vehicle to achieve its top speed and economy targets, the initial prototypes were shown to management who instantly took a dislike to the design reasoning that they did not want to damage the Rootes Groups reputation by selling a car that resembled a bubble car.

By this time the Suez crisis was in full swing and the company desperately needed a small vehicle, spurred on by the success of the Austin A30 and Ford popular the board pressed ahead with the project but stating the vehicle must be larger and of a substantially better quality. The project was now named "Apex" and was overseen by Technical Director Peter Ware developing the model to the updated requirements.

No suitable engine was available within the group for use within the new small vehicle and were forced to source an engine from an external source; Tim Fry did not have to search very far having identified Coventry Climax as a suitable supplier. The engine of choice was the Coventry Climax FWMA; this unit was the successor to the 750cc FWC that powered highly successful Lotus campaigns in competitive motor racing series. The high, free revving nature of the engine was not entirely suitable for a road car and the unit was de-tuned and modified to be more refined, reliable and altogether more suitable for an every day road car.

Whilst cars featuring a rear engine layout were fast becoming outdated development was too far advanced to convert the vehicle to a traditional front engine rear wheel drive configuration – Rootes wanted to penetrate the lucrative small car market as quickly as possible. The vehicles styling was influenced heavily by the Chevrolet Corvair that also had a rear engine layout, Peter Ware undertaking the styling of the vehicle, the two door body shell featuring an opening rear window that was very unusual at the time.

The 750cc capacity was expanded to 875cc; retaining the all aluminium lightweight construction the engine was installed with an entirely new aluminium cylinder head with overhead camshaft but retained the overhead camshaft design. The majority of internal components were modified for the new application, a 10.0:1 compression ratio was used and the engine was fitted with a single Solex B30 PIHT semi downdraught carburettor, in this form the engine delivered 39 bhp @ 5,000 rpm and 52 lb/ft of torque at a respectable 2,800 rpm.

Adrian West was drafted in as the Senior Transmission Engineer to oversee development of a new gearbox that featured a transaxle design whereby the gearbox and the differential were housed in the same aluminium casing. Synchromesh was fitted on all four forward gears, first and second gear were matched to the engines free revving nature but third and fourth gears were elongated to provide the desired economy and reduce noise at speed. The unit was both strong and very light with a precise gear change, at the time of launch the Imp was considered to have one of the finest transmissions on the market.

Management within the Rootes Group believed the path to survival was through expansion seeking financial assistance from the government. Rootes having already earmarked expansion of their manufacturing facility in Ryton, Coventry were subjected to pressure from the government to develop a new site in an area needing economic regeneration making this a condition of any financial assistance.

Funded through favourable government backed loans and grants Rootes built a new purpose built factory at Linwood in Scotland around twenty miles away from the unemployment black-spot of Glasgow. Employment in Glasgow had been hit hard with the contraction of the ship building industry and a high proportion of the six thousand employees recruited for the factory had a background in the ship yards.

The Linwood facility was not a success for the group for a number of reasons; firstly the employees were not well versed with the intricacies of mass producing automobiles leading to build quality issues. Furthermore employment relations were poor and the factory suffered from a number of industrial disputes that led to a total of thirty one stoppages in 1964 alone reducing production to a third of project capacity. Logistics also played a role in the downfall of the facility with the engine castings being manufactured at Linwood before being transported three hundred miles to the Ryton facility for machining and assembly before returning to Scotland for installation in the vehicles – clearly inefficient at best.

The Imp was launched in May 1963 and received favourable comments from the press and Rootes estimates of 150,000 vehicle sales per year seemed fairly plausible. The situation soon turned sour as the Imps rushed development came back to bite the company with owners experiencing a multitude of issues ranging from faulty automatic chokes, defective water pumps leading to overheating, internal water leaks and other niggling issues.

Wanting to maximise the potential of the new platform Hillman released a number of variations of the imp over the coming years including the Singer Chamois, Commer Imp Van, Sumbeam Imp Sport, Singe Chamois Coupe amongst others. No significant development effort was placed in the Imp over the coming years, front wheel drive replacement projects were never taken forward and the car was left to slowly die falling further and further behind the ever evolving competition.

Production ended in March 1976 when the final Hillman Imp rolled off the production line by which time 440,032 examples had been manufactured. The Imp was not a resounding success for the group with the model achieving it production record of only 50,000 vehicles per annum in 1964 before tailing off to only 19,000 vehicle during the last full year of manufacture, Despite being amongst the cheapest vehicles in its market segment and receiving positive motoring press reviews sales suffered badly due to a poor reliability record furthermore the vehicle was up against the might of the Mini that utilised a front wheel drive configuration and had become a fashion statement being “the car to have”.

The Facts


875cc Four Cylinder All Aluminium





Compression Ratio:


Fuel System:

Solex B30 PIHT Semi Downdraught Carburettor

Maximum Power:

39 bhp @5,000 rpm

Maximum Torque: @ 2,800 rpm


4 Speed Manual

Top Gear:

15.2 Mph / 1000 Rpm


Drums Front / Drums Rear

Kerb Weight:

711 Kg

Max Speed:

80 Mph


25.4 Secs