Moving Down, Scaling Up (Part Three)

The 1963 Hillman Imp was Rootes’ answer to BMC’s Mini, but a latecomer to the market and, ultimately, a commercial failure. We conclude its story.

1965 Hillman Imp Mk2 advertisement (c)

Autocar magazine had been given early access to an Imp De Luxe for testing and published its road test just a day after launch. The price including tax was £532, a £24 premium over the standard version. The reviewer praised the new engine’s smoothness, quietness and willingness to rev. They noted that, despite an unusually high 10:1 compression ratio, it ran without any trace of ‘pinking’ or ‘run-on’ on Premium(1) grade petrol.

The recommended top speed of 70mph (113km/h) was easily exceeded, and a maximum of 83mph (134km/h) was recorded one-way. The 0 to 60mph (97km/h) time was measured at 23.7 seconds. Fuel consumption over the course of the road test was 38.1mpg (7.4 L/100km).

No coolant temperature gauge was fitted, and the reviewer had to add a pint (0.57L) of water to the empty header tank every 300 miles (485km). This was a portent of a significant problem with the Imp that would emerge later. Two unusual features were a pneumatic throttle linkage and an automatic choke. The former was quite sensitive and took some getting used to, but the latter performed perfectly during the test. The gearchange was light and precise, with an unbeatable synchromesh. The clutch was smooth and progressive, although the articulation of the pedal was somewhat awkward.

1961 Autocar road test (c)

The unusually wide differential in recommended tyre pressures, 15 p.s.i. (1.03 Bar) front and 30 p.s.i. (2.07 Bar) rear, and positive front wheel camber counteracted the rear-biased weight distribution, and the Imp tended to understeer when pushed hard, a characteristic described as “fail safe” by the reviewer. Directional stability was better than usually found with rear-engined cars, aided by precise rack and pinion steering. The ride was generally good but became unsettled over ‘washboard’ ridged road surfaces or deep potholes, when significant scuttle shake was experienced.

Overall, the reviewer rated the car highly and praised its roominess and its “superb little engine and transmission”. So, a positive reception at launch for the Imp, but trouble would soon follow. Despite its protracted eight-year development period, the Imp was launched with a number of features added late in the process and insufficiently tested. Issues with these features would soon damage its reputation.

1961 Hillman Imp dashboard (c)

Moreover, by 1963, the fashion for rear-engined small cars, so prevalent in the mid-1950’s when the project had commenced, was in retreat. BMC’s revolutionary transverse-engined FWD Mini had shown the way forward, although other manufacturers were initially slow to react. Fiat dipped a cautious toe in the water with the 1964 Autobianchi Primula, but it would be another five years before the parent marque would commit to the layout with the 1969 launch of the Fiat 128.

Notwithstanding its arguably outdated layout, the Imp had many positive qualities and sales started strongly, with around 33,000 finding buyers in the eight months from launch to the end of 1963, followed by another 50,000 in 1964. By the end of that year, however, the car was developing a reputation for unreliability.

Autocar’s launch road test of the Imp had noted its prodigious thirst for engine coolant. Insufficient airflow to a small rear-mounted radiator and an inadequate water pump caused the engine to run hot. The absence of a temperature gauge, or even a warning light, meant that this issue was often overlooked by drivers, sometimes with catastrophic results. The all-aluminium engine could suffer a warped cylinder head and blown head gasket, or even a complete seizure.

Other problems were experienced with the automatic choke and pneumatic throttle linkage. The resulting damage to the Imp’s reputation caused a fall in sales in 1965 to under 43,000 units. This was worrying for Rootes so early in the model’s life, especially after the company had widened the range by introducing an upmarket version called the Singer Chamois in late 1964.

1963 Hillman Imp. The unusual positive camber of the front wheels is evident in this photo (c)

The cost of developing and launching the Imp, together with the considerable investment in the new Linwood plant, had placed Rootes’ finances under considerable strain. This made the company receptive to an approach from Chrysler Corporation and, in June 1964, the US automaker bought 30% of the company’s ordinary shares and 50% of non-voting preference shares, leaving control still in the hands of the Rootes board and senior management(2).

Chrysler was allegedly the driving force behind an interesting but stillborn 1964 proposal for a four-door ‘Imp’.  This was little more than a Simca 1000 with lightly modified bodywork. This proposal was seen as a means of extending the Imp range for a minimal investment.

1964 Hillman Imp four-door prototype (c) RMP

Rootes decided that a relaunch was needed to address the Imp’s issues. A Mk2 version was unveiled in September 1965, with a raft of improvements to address the problems identified. These included a new water pump with modified seals, a larger cooling fan and a new head gasket, a conventional cable throttle linkage(3) and a manual choke. Other improvements included two steel struts behind the dashboard to reduce scuttle shake on rough roads and a rear undertray to protect the engine from road dirt. The inlet and exhaust ports in the cylinder head were also enlarged slightly. No improvement in performance was claimed for the latter change, but it ensured better consistency in engine build and power output. These mechanical changes were accompanied by some internal and external trim embellishments.

At the same time, the Imp range was rejigged. The basic model was dropped and a new Super version introduced. A van version, with new bodywork aft of the B-pillars, was launched under Rootes’ Commer commercial vehicle marque.

1968 Hillman Imp van in Rootes/Chrysler livery (c)

The package of improvements was comprehensive, but the Imp struggled to recover from the reputational damage caused by earlier issues. The situation was complicated by the fact that labour relations at the Linwood factory were poor, making it difficult to implement changes, and build quality remained variable.

A twin-carburettor version of the Imp was launched in October 1966 as the Sunbeam Sport and the same setup was offered on the Chamois. The next significant addition to the range was the Hillman Californian in January 1967. This was a coupé version of the Imp. The body below the DLO was unchanged but the car was given a more sloping rear screen, which was no longer inset between the C-pillars and did not open. The car was given more upmarket trimmings. A coupé version of the Singer Chamois followed in April, which was not meaningfully different to the Californian. More significant was the Hillman Husky, a version of the Commer Imp van with rear side windows and a rear seat, to create a makeshift estate car.

An oddity of the Imp up to 1967 was the pronounced positive camber of the front wheels. This means that the wheels sat, not at right angles to the road surface, but sloping outwards at the top. Together with the low 15 p.s.i. (1.03 Bar) front tyre pressures, this was intended to reduce front wheel grip and counteract the tendency of the car to oversteer because of the rearward bias of its weight distribution. From mid-1967, the suspension was adjusted to correct this, resulting in a more normal appearance and reduced tendency to understeer.

In October 1967, Rootes launched the upmarket Sunbeam Stiletto(4). This was based on the Californian but was distinguished by a smart twin-headlamp front end for which the Imp’s castellated bonnet always seemed to be designed. Rootes was now offering saloon, coupé estate and van versions under four different marque names, but this had little if any positive impact on sales.

1970 Sunbeam Stiletto Coupé (c) the

Chrysler effectively took control of Rootes in 1968 and there followed a further round of mainly cosmetic revisions to the range in October of that year, including a new interior, seats and dashboard. Cars with these revisions were informally referred to as Mk3, but never officially carried that designation. The Commer marque was discontinued and the van was rebranded Hillman. In April 1970, the Singer models were dropped, followed by the Husky estate and van in July.

The remaining models limped on without meaningful further development and with little promotion until production ended in March 1976. The Imp’s engine, in enlarged 928cc form, would however again see service in the 1977 Chrysler Sunbeam, a stop-gap supermini based on a cut down Avenger floorpan.

Over thirteen years on the market, total sales of the Imp and its derivatives amounted to just under half a million units. After its early reliability issues were addressed, it was a pleasant and amiable small car, but it was, in hindsight, too late to market and its reputation never recovered from the early problems. Together with the financial and management burden of the troublesome Linwood plant, the failure of the Imp was the major reason for the demise of the Rootes Group as an independent UK motor manufacturer.

(1) Also known as four-star (98 Octane rating) petrol. There was also available a ‘Super’ five-star (101 Octane rating) petrol, which would normally be used in high compression ratio engines.

(2) Sadly, William (Lord) Rootes passed away on 12th December 1964.

(3) A retrospective modification was also offered for the pneumatic throttle linkage that resolved the problems with it.

(4) The name referred not to a style of women’s shoe, but to the word’s earlier meaning, a slim-bladed dagger. This connected the car to the larger Sunbeam Rapier coupé.

Author’s notes:
(1) My thanks to fellow DTW contributor, Robertas Parazitas, for his insights and contributions to this piece.

(2) Intrepid British auto journalist Archie Vicar also road-tested the Imp. His no-holds-barred report may be found here.

Author: Daniel O'Callaghan

Shut-line obsessive...Hates rudeness, loves biscuits.

35 thoughts on “Moving Down, Scaling Up (Part Three)”

  1. Here’s a picture of the Imp’s pneumatic throttle control (the pedal presses on the black pump which then sends air through a hose to a similar pump at the carb

    here the carb end

    I’ve yet to see a single car with an automatic choke that works really properly.

    1. Nice photos, thanks Dave. Regarding automatic chokes that worked properly, the one on the VW Beetle was pretty reliable in my experience.

    2. Hallo Dave and thanks for the photos. What I don’t understand are the merits of this pneumatic throttle control.
      A clutch pneumatic actuator would make more sense – in a bigger engine of course.

      Nice series Daniel, thank you. A very cute looking car the Imp is. I vaguely remember it from my childhood. Hillmans had a reputation of “slow but solidly build cars”, at least in my mind!

    3. The Imp needed a very long throttle cable, potentially troublesome. The pneumatic system was seen as a cheap and easy way around the problem.

    4. Hi Constantinos. Your impression of Hillman before the arrival of the Imp was pretty much correct. The Imp was a brave leap for a conservative company but, unfortunately as it turned out, one in the wrong direction.

    5. Constantinos, the Imp did have an hydraulic clutch which has the same advantages as pneumatic, instead of the cable alternative. Not sure any cars have had a pneumatic clutch?

      I had an early car (parts donor) in the mid-00’s with a pneumatic throttle that still worked, at least driving it briefly around a field. I’ve read the issue was a check valve rusted and would leak – using stainless steel instead would have solved it. The alternative cable (which works) is about 2.7m long.

    6. The pneumatic throttle mechanism was made by Lucas – need I say more?
      Originally the mechamism worked pretty well until Lucas changed the material of one washer in the carb side mechamism from stainless steel to something else which didn’t work.

      There were cars with kind of a pneumatic clutch. Fichtel & Sachs made a ‘Saxomat’ vacuum mechamism similar to a brake servo which was used in semi automatic gearboxes like in old VWs or Ro80. You touched the gear lever and triggerd a micro switch which in turn controlled a valve in the vacuum tube and operated the clutch.

  2. I remember in 60s London, our next-door neighbours had friends/relatives who visited twice in a Hillman Imp. On both occasions the Imp went home on a trailer. The next time they visited they were in an NSU 1000…..
    Clearly the Imp was launched prematurely because of financial problems at Rootes, and instead of helping the situation this decision ultimately made things worse.
    Since rally-Imps used a 998 cc engine I always wondered why the front-engined Sunbeam only got 928cc. Nevertheless that little engine/transmission unit was a gift to “specials” builders.

    1. Thanks Mervyn for the reply.
      Still, as Daniel says, other aircooled rear wheel driven cars had an automatic choke and a cable throttle wire fitted with less problems.
      Well, maybe they had something in mind that simply didn’t work out for them. Bravo for the idea though.

  3. They sold well because they mainly worked (leaving the daft throttle design] and made the Mini look very cramped inside, which it was.

    1. Hi Vic, I’m not sure how much more roomy the Imp was, but the impression of interior space was certainly enhanced by slim pillars and a deep glasshouse:

  4. Am I right in thinking that the Imp is one of the very few post-war cars with a front swing axle(the other I can think of being the Allard J2)?

    And thank you very much Daniel for this insightful series 🙂

    1. Thanks Roberto, glad you enjoyed it. The question you ask about front swing-axles is above my lowly pay grade here at DTW Towers. I can’t think of another example, but I imagine that someone amongst our commentariat will know definitively.

    2. The Allard, like the Lotus 6 (most of them anyway) was made of Ford parts. You took a beam front axle from a Ford, cut it in half, and welded pivot bushes to the cut ends. Hey-presto, cheap independent suspension. I had one on my first car ( 8/10 HP Anglia ).

    3. Front swing axles – check the Goggomobil, which inspired the Slug / Apex from the start:

    4. 1956 Lotus Eleven (swing axle front suspension borrowed from a pre-war designed Ford Prefect)

      Ford F-series light duty pickups used swing axles (Twin-I-Beam, Twin Traction Beam) from 1965 until the mid 1990s.

  5. Here’s the Coventry Climax engine in its original application:

    You see why it had to be that light.

  6. While not disagreeing with the fact rear-engined cars were beginning to be seen as old fashioned by the 1960s after the Mini was launched, is it really fair to criticise the Imp on just that basis when the similarly sized and rear-engined Fiat 850 appeared a year later with much more commercial success over roughly the same period?

    It is too simplistic a conclusion when in reality Rootes were just unfortunately dealt with a really bad hand by both the government as well as the unions (particularly during the Imp’s development during the late-50s to early-60s in Rootes critical period of expansion), followed by a clueless parent company in Chrysler that found itself beset by its own problems and bad management from the 1950s onwards until the late-1970s.

    It is also worth mentioning that the 928cc engine was originally planned to be introduced in the late-60s as part of a completely revamped mk3 Imp that was supposed to feature a whole raft of changes to remedy its various issues as well as make it cheaper and easier to produce, etc instead of the Chrysler rationalised mk3 Imp that did reach production.

    Additionally though it was envisaged the Imp engine would have a displacement range of 800-1000cc, in reality outside of the 998 engine used in the Imp Rally homologation special Rootes discovered the production Imp engine could not grow to reach 1000cc. It was initially believed the limit was 928cc though a few decades later the true displacement for the Imp engine was actually 948cc.

    Had circumstances been better for Rootes they could have developed a more practical tall-block version of the Imp engine with scope for displacements from 1000-1150cc+, reputedly a red “ImpWerks” Hillman Imp Van (Reg: RVP 530 G) owned by one Martin Dingle even featured an Ian Carter long-stroke Imp engine displacing around 1300cc.

    1. Hi Bob. I don’t think I (or any of the commenters above) attributed the failure of the Imp solely to its rear-engined layout per se. Despite its protacted development, some features like the automatic choke and pneumatic throttle were insufficiently tested and proved problematic. Likewise, the overheating issue really should have become apparent before launch. How it didn’t remains a mystery.

      As I said in my conclusion above, once the early reliability issues had been sorted out, the Imp was a pleasant and amiable car, but its image had been tarnished and it never really recovered.

    2. Agree that there were other factors that contributed to Imp’s problems and damaged its reputation from which it never really recovered from, it is just one of those typical cliches that tends to get bandied around when it comes to comparisons between the Imp and the Mini (that and the fact that despite the Imp’s engine its dimensions were closer to the 1100).

      Perhaps one reason why the overheating issue did not become apparent was due to a combination of the rush to get the Imp into production, the costly and logistical nightmare of building a factory in Linwood instead being allowed to expand their existing factory, in addition to a strike at Acton from 1959 to late-1961 known as the “Honeymoon Strike”.

      From the following link below –

      “In 1959 a minority group of Rootes Group workers had begun to strike at regular intervals, much to the annoyance of the majority. The workers concerned were from a Rootes subsidiary company, British Light Steel Pressings Ltd. of Warple Way, Acton, London. The shop stewards at the Acton factory first learned how to shout strike when a couple of newly weds at the factory, who were night shift workers, asked to be transferred to day shift. This was done and 1,500 workers came out on strike! At a time when strikes were relatively rare, this one became known as the ‘Honeymoon Strike’.

      The Rootes family had begun to regret ever taking over the firm but at the time it had become necessary to increase their pressing division, to keep up with the demand for their vehicles.

      Strikes at the Acton factory continued and on 1st September 1961, 1, 000 workers walked out again, bringing the total stoppages since 1st January 1961 to 82. These were crippling the Rootes Group and there was nothing they could do about it. The strikes, which were mainly unofficial and against union advice, had caused the loss of over 27,000 man hours at the Acton factory, which in turn had caused the loss of 17,000 man hours at other factories. This latest strike was called because of ‘fears of extensive short time working and large scale redundancy’. When management refused to hold talks with the men’s leaders (not the unions), they walked out.

      On Monday, 4th September 1961, the strikers decided to send delegates to the TUC Annual Conference at Portsmouth, to try to persuade the TUC to adopt a new national policy in relation to the car industry. They wanted 52 weeks pay per year for all workers in the car industry, no matter what the situation. They also told the TUC that they did not want any interference by union officials. “We feel this has been allowed to develop as a local problem because of lack of action from outside and we think we are in a better position to get a settlement with our management” a spokesman told Acton Gazette reporters. He continued, “We don’t want the type of assistance the union officials gave us last time, when we stopped work over a short time dispute. On the first day we stopped, we were ordered back to work without anybody considering why we had come out.” The strike delegates achieved nothing at the conference. By 18th September 1961, the strike had brought the Rootes Group almost to a standstill with over 6,000 workers from the various Coventry factories being laid off. Only the non-production line staff continued to work.

      Until now, Lord Rootes had refused to comment on the strike, but on the 26th September 1961, he made his first statement to the workers concerned: “Return to work by Thursday 28th September or be sacked.” The strikers ignored the threat, and on Thursday, 28th September 1961, all 1000 workers were sacked. A recruitment drive was started to replace striking workers. The strikers objected to this, protesting that the Acton Labour Exchange was engaged in strike-breaking by sending men down to the factory for jobs – jobs which, as the committee said: “They will go back too, once the management accepts to abide by the rules of the committee.” Rootes replied: “We regard the strikers as ex-employees. We have invited applications for their jobs. Some strikers have re-applied and we believe others will follow.”

      The Rootes Group had complete backing from all their other employees, from the unions, and from the wives of the strikers (this was given a great deal of publicity). But the sacked strikers would not listen, stating that “We are determined to see it through.” As the weeks rolled on, 8,000 workers from other factories were made redundant. Rootes were now having financial problems, and it was in fact the beginning of the downfall of the Rootes Empire. Controlled by five men, the strike had caused irreparable damage to the Rootes Group and its finances. There was a call for a public enquiry after it was disclosed that the strike was Communist planned and directed. By 2nd November 1961, Rootes had found other manufacturers to supply them with the body panels that should have been produced at the Acton works. They had also re-engaged 1,750 workers at their Coventry factories in an attempt to get the production lines rolling once more. The strikers from what was now labelled “the dead duck strike” were gradually drifting back, and by 30th November, Acton’s work force was up to 680, 430 of whom had been strikers. By December 21st 1961, only 120 men were still out. After a final meeting, they decided to go back, but Rootes turned them away, giving them £40 compensation as a token gesture. Only one of the strike committee members was re-employed.

      The dispute may have been over, but it was only the start of the Rootes Group’s problems. Their first priority was to build up their workforce to enable them to fulfil the outstanding orders. In November 1962, Rootes announced the total cost of the Acton strike up until the year ending 31st July. They showed a loss of £891,088, compared with a profit of nearly £3 million the previous year. This type of loss Rootes could not afford. They were already heavily committed to a new project, the Hillman Imp, and the opening of a new plant at Linwood in Scotland where it was to be produced. This turned out to be the biggest phase of expansion in the group’s history, and losses at this time were the last thing Rootes wanted.”

    3. When we talk of reliability we forget that the Mini suffered serious reliability issues at launch, and it was ultimately its’ adoption by the rich and famous that made it such a hit.

  7. Regarding the overheating issue, my theory is that development engineers drive fast and yet with mechanical sympathy. I would think that the engine would be fine when there was a good air flow. I know that the Imp was also given to students as a means of acquiring extra development miles; however, being students, they drove the cars fast, on quiet roads. The problems would have started when people began driving more normally, including sitting in traffic jams.

    Although the Imp was developed over a long period, I’d question how long was spent on the final product – I suspect it emerged pretty late and things were rushed.

    Finally, an Imp advert, featuring the actor, Ray Barrett. If his voice seems familiar, it may be because he voiced characters in Gerry Anderson productions (Stingray, Thunderbirds).

    1. Hi Charles. That explanation regarding testing sounds pretty plausible. Hard driving at high speed with adequate airflow was probably less problematic than slow driving in heavy traffic.

      Thanks for posting the advertisement. Thunderbirds was my absolute favourite as a child!

    2. Someone has reconfigured the Thunderbirds opening and closing titles, featuring Elon Musk’s Spacex organization. I think it works very well indeed.

    3. That’s brilliant, Charles! I cannot decide whether Elon Musk is a genius or an evil Bond villain. I suppose that means he’s probably both!

  8. Always love reading articles about the Imp (owned them for >20 years) so thanks for a fine piece Daniel!

    Apart from the rushed/incomplete development – in one of the history books there was a quote saying that with all the running of water pumps on the test rig their problems were known about, but nobody solved them – the launch date set well in advance could not be delayed with the Duke of Edinburgh booked to open the factory. One gets the impression they would have delayed it if they could have.

    The cars did have a water temperature warning light, but it was combined with the oil pressure warning (the orange light of doom) . Water pumps were prone to leaking, and the coolant quantity (and radiator size) were marginal at best, leaving little room for error. Also at highway speed the air is sucked in from the rear of the car by the powerful fan, forward through the radiator and leaves under the car, where it eddies at the rear of the car… I’ve only had overheating issues at high speed.

    In Australia the Imp sold strongly at first, so much that the CKD kits ordered took many years to clear after sales dropped once the teething issues surfaced. This wasn’t helped by the prevalence of unsealed roads in Australia; I was told by a former mechanic from a small rural dealership of pistons needing to be replaced at 5-6,000 miles due to dust-induced wear! There were 2 major revision of the air intake to try and source cleaner air, as well as a much larger filter.

    1. Hi John. Thanks for your kind words, and for sharing your recollections of the Imp. I wasn’t aware of the shared warning light. One would think if they went to the trouble of installing a water temperature sensor, a separate bulb would have been been a very modest additional expense!

  9. Well – I go away for a few days (conducting one of five Jowett Javelins which have been exploring the network of single-track roads in the upper Dee valley to the west of Llangollen) and find I’ve missed the final instalment of this celebration of what should have been a great car. Thank you Daniel for telling the tale so well and thank you to everyone else for making the catching up so entertaining. Only one missing element – nobody seems to have mentioned the 3-wheeled Imp, otherwise known as the Bond 875…..

    1. Welcome back, John, and hope you had a great time exploring the Dee Valley. As for the Bond 875, however, I think the Imp’s issues were modest compared to this:

      I think I know exactly the right DTW scribe to investigate the Bond (clue: it’s not me!)

    2. Since you have mentioned the Bond 875, I’ll do the obligatory mention of John Surtees setting a lap record at Silverstone in one (presumably in a fairly specific class!)

  10. Thank you Daniel, you might not remember it but you replied to a comment from me saying that an Imp article might be on the cards – you have certainly delivered.

    Really enjoyed this, you may not know it but following the Chrysler takeover there was a decontenting program (see also Project Drive, Rover 75) which meant the deletion of some strengthening brackets, a cheap and nasty fascia and various other cost cutting measures.

    In fairness and counterpoint the later engines were significantly better propositions than the early ones.

    Apropos clutches, I don’t think there’s any way you can have an air clutch without an actual compressed air source, too much compressibility in the working fluid at the pressures needed, the hydraulic clutch is perfect in this application – air clutch is only useful if a servo action is needed.

    Thanks again Daniel

    1. You’re most welcome, Rick. Glad you enjoyed the piece! I wasn’t aware of the Chrysler decontenting programme, so thanks for mentioning it – every day’s a school day!

  11. Sorry, a bit late to this party. This series has reminded me of the link between the Imp and the Alfasud – both suffered from their respective governments coming over all directorial (if not dictatorial) by insisting on production facilities for the cars being built in high unemployment areas which had a paucity of a skilled/ experienced workforce.

    1. Hi S.V. I’m happy to report that we have a retrospective on the wonderful Alfasud coming up in the near future. Stay tuned!

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