Emboldening the Spridget has become an industry.
The most prolific period for Spridget engine transplants was the 1970s. By then there was a good supply of second-hand Midgets and Sprites cheap enough for experimentation, and a far broader range of suitable engines. Fiat twin-cams were a popular choice, available cheaply from rotten or written-off 124s and 125s, and often with the added attraction of a five speed gearbox. In the USA and Australia, some Japanese engines found favour, including the twin rotor Mazda 12A. In Britain, the Ford Kent variants were the default choice, plentiful and easily fitted, with far more power than could be cheaply and reliably extracted from an A-series.
Creating these hybrids was not a task to be taken lightly, requiring mechanical knowledge, a variety of skills, a well-equipped workshop, and often an iron will and determination.
In 1971, Formula 2 racing driver David Martell saw a potential market for off-the-shelf re-engined Midgets, in part emulating Jack Brabham’s Sprite-Climax venture ten years previously, but with a different business strategy. His Bedfordshire-based company, Car Preparations built and marketed Midgets fitted with Ford crossflow engines and re-branded as the Atlantis 1600GT. Despite the unfamiliar name, the cars were distinguished from the Abingdon original only by rather egregious decals and front quarter-bumpers in place of the usual full-width items.
Only new ex-factory Midgets, bought complete, were used and they came specified with a number of options appropriate to the increased power; brake servo, 3.721:1 rear axle ratio and a 5/8 inch gauge front anti-roll bar. The cooling systems were upgraded with a larger capacity cross-flow radiator with a remote header tank, and at the rear, the stock Midget axle was more effectively located with a pair of radius arms and a Panhard rod. A modified MGB fuel tank was fitted, providing a ten gallon capacity, rather than the original’s barely adequate six.
As well as the extra engine capacity, the Ford engine had some significant advantages over the Midget’s 65bhp A-series. The crossflow cylinder head gave each valve its own port, and far more porting room than the A series, whose five ports (two inlet, three exhaust) were on the same side of the engine as the pushrods. The Ford engine was oversquare, with a crankshaft stroke almost four millimetres shorter than the A-series. That crankshaft ran in five main bearings, two more than the A-series had.
Ford did not share the BMC and Rootes fetish for twin carburettors; those used to the pestilential task of balancing pairs of SUs or Zenith-Strombergs would have welcomed Ford’s choice of a single twin-choke Weber. The Ford single-rail close ratio gearbox would have been a revelation to users of the old A35 derived transmission; synchromesh on first gear, near-silent running, and class leading shift quality.
There was an impressive thoroughness about the management and promotion of the Atlantis conversion. Installations on pre-owned cars were not offered, although part exchanges were an option. The A series engines were sold complete and as new to a trade customer, keeping down the price of a new 1600GT to £1166. For comparison, a Midget cost £970, and an MGB roadster £1308. With its 86bhp (DIN) Ford engine the Atlantis easily outperformed the MGB; Autocar recorded a top speed of 110mph and a 0-60mph figure of 10.8 seconds.
At the Atlantis launch in spring 1971, David Martell promoted the car widely to the media, with road tests published in Motor Sport, Autocar, Cars and Car Conversions, Safety Fast, and Hot Car. Reports were favourable, highlighting value for money and the beneficial change of character achieved with the Ford engine and gearbox. Hot Car described the Atlantis as “the Ford-British Leyland merger the Financial Times didn’t hear about”.
Their evaluation was more thorough than other publications, and criticised the disturbing axle tramp experienced during standing-start acceleration tests, while noting that Car Preparations were re-thinking the axle location geometry to address the problem. A half-shaft broke during Hot Car’s tenure. The tester tactfully observed that this may have resulted from six publications road testing the car, but nevertheless “Atlantis owners who modify their Ford engines may get trouble”.
Although the Atlantis received widespread and favourable media attention and was advertised in a manner reflecting the attitudes and preoccupations of the time, little is known of how many were delivered, or how long they were available. Perhaps it arrived a few years too late. The target customers’ aspirations had moved from traditional two-seaters to rally-inspired tin-tops, especially the Ford Escort Mexico which shared the Atlantis’s powertrain and cost £1219 in May 1971.
In the decades which followed, the fervour and ingenuity of Spridget engine-swappers was unabated. The portfolio of donor engines had expanded, along with the imagination and budgets of converters. Some Rover V8 conversions are said to exist, and there were further Jaguar XK installations. However, some serious four cylinder power was available by the late 1980s and into the following decade, with Toyota 4a-GE, Nissan SR20DET, Ford Sierra Cosworth and BMW S14 units appearing in Spridget engine bays.
One enterprising individual even set out to out-fright The Fright, taking a 73/74 round-arch Midget and extending the wheelbase by 100mm to accommodate a Jaguar V12 engine. Drive was taken to the rear wheels by way of a Porsche 928 transaxle. The V12’s cooling load was handled by a large radiator and cooling fans mounted in the Midget’s boot.
Motorcycle engined Midgets include several with the 1300cc Suzuki Hayabusa in-line four, and one example fitted with an 1100 cc V4 from a Honda Magna V65 custom bike.
For the less ambitious, the more suitably sized and shaped Ford Zetec 1.6-2.0, Rover K-series and Mazda B6ZE engines became widely available in the 1990s and continue to find favour.
As I write this, almost 43 years have passed since the last MG Midget left Abingdon, yet the Spridget engine transplant industry thrives. Sussex-based Barratt Engineering offer kits to fit the Nissan CG engine, with or without a five speed RM7E Suzuki gearbox. All necessary installation parts are supplied, at a cost of between £2200 and £2600. That excludes fitting, and the engines and gearboxes themselves, still readily available but likely to require overhauling before installation. Not a cheap pursuit, but the reader will have already realised that the love for these cars and the urge to perfect them transcends vulgar money or – some might think – rational judgement.
Even British Leyland could not resist the engine swapping bug. In late 1974 the Midget, got its own power unit transplant, although the sprawling conglomerate’s extensive arsenal could not provide anything as well suited to the Midget as David Martell’s chosen Ford Crossflow.
To be continued.
 According to one description, the extra inches were inserted within the bulkhead zone, with the visual giveaway of an extended external panel between the trailing edges of the front wings and the leading edge of the door opening.
 The Nissan CG “Clean Green” engine is an all-aluminium 16 valve twin cam unit mainly used in the 1992-2003 Micra. Not only is it close in size and proportions to the BMC A-series, it also has 998cc and 1275cc capacities, as well as a longer bore and stroke 1348cc version.
 The Suzuki gearbox was used in the 2001-2005 Jimny.
Reference sources: Hot Car July 1971/ Autocar May 20, 1971 /jacobsmidget.com/ midgetandspriteclub.com/ spridgetguru.com/ sebringsprite.com/ barrattengineering.co.uk
15 thoughts on “Elemental Spirit Part 6: I Will Not Go Quietly”
Good morning Robert. I had no idea the Spridget was treated to so many engine mods. 110mph must have been a bit hair-raising, never mind the V12 conversion!
Isn’t it a shame that BMC/BL failed to develop the Midget, given the appetite for more power and performance. The belated installation of the Triumph 1,500cc engine was hardly an adequate response. That said, my 1978 Midget 1500 was so crude and noisy that you always thought you were travelling much faster than indicated by the speedometer.
The one time I drove a Spridget I found it really enjoyable. It was an honest and simple little car. It was by no means perfect, but I didn’t find myself thinking ‘this thing needs more power’. If I’d wanted to shell out more for a faster compact sportscar in the 60s or 70s, I’d have spent it on an Elan. There seems a real degree of stubborn perversity in all this re-engining. After they’d stretched it, fitted the V12 and an independent rear end, why didn’t they rebody it with … oh what about an E-type replica body? I wouldn’t use the ‘you can’t polish …’ cliche here because that would be totally offensive to the decent little Spridget, but once you factor in the time spent on these conversions, they weren’t cheap. Of course, as Robertas says, none of this is really rational, but if you really love something, why don’t you just accept it for what it is?
Yes – it’s amazing the lengths people would go to – to the extent that it’s pretty far removed from being a Spridget. If I had wanted to improve a Spridget’s performance, I think I would have gone to Downton Engineering or somewhere similar (although it sounds as though it could have been a bit of an adventure).
“If I’d wanted to shell out more for a faster compact sportscar in the 60s or 70s, I’d have spent it on an Elan.”
I think we all would, although some may have chosen a TVR, Marcos, or even a Ginetta. However, a quick check of a mid-1966 Autocar confirmed my suspicion that the £1416* which Lotus asked for an Elan would buy nearly two and a half Spridgets, or put you within £450 of an E-Type.
Some of the contemporary road tests of the Brabham Sprite and the Atlantis 1600 make comparisons with the Elite and Elan. The car weights are very close, but the Lotuses have far more power, a deficit which the engine transplants narrowed. So for prospective owners, they were something of a “Poor Man’s Lotus”, and also a far easier car to live with.
The Sprite and Midget chassis was not designed and developed with the same racing-inspired rigour as the Chapman cars. However MG’s engineers were more thorough in ensuring that their end product would not give much trouble, and if it did, it wouldn’t be too serious.
*In the UK you could save some money by ordering your Elan in “component form”, and assembling it yourself. This had to be done without the aid of instructions from the manufacturer, which were not permitted under the UK tax rules which exempted ‘kit cars’ from Purchase Tax.
Robertas. After I’d posted that I wondered if there was a whiff of ‘let them eat cake’ to it. Though I was thinking more of the Atlantis at £1,166 against the Lotus at £1,490 or so. Of course that Lotus figure excludes purchase tax which would have taken it up to a heady £1,942, but as you point out you could avoid it if you ticked the kit car box. That said it’s easy to point out that the Lotus is then ‘only’ £330 more, but that could be many weeks wages back then. Also regarding cost differences, the Atlantis was just £200 more than the standard car which, even allowing for the benefit of selling on the A-Series, doesn’t seem much for all the work and materials involved. Possibly the car’s demise was due to a realisation that the business plan was flawed with the price set between Spridget and MGB at what it ‘should’ cost rather than what it did cost..
And, yes, the hypothetical young man with a little bit more money to chuck at a sportscar into whose mind I’m putting myself, might well rue buying the Elan when the lights refuse to rise and the gearstick falls off in his hand for the second time. Particularly if he had been fortunate enough to afford the fully built option and was now feeling it would have been wiser to complete the construction himself. On the other hand I still remember the all so nimble Elan I was following in the New Forest whose driver flicked the car round effortlessly to miraculously avoid a car pulling out from a junction, when I was sure that a very bad accident was inevitable.
On the matter of tax-avoiding build-it-yourself cars, I present this from my archive:
I’m afraid my credulity is sorely stretched.
Fantastic article, thank you for sharing. Kinda shows once again that the demand for BL’s cars was always there, but they failed to respond to any of it.
You mentioned a Triumph engine; I assume it was the dolomite’s? How good where they overall and could they have been adequate replacements for the old A series?
More, as they say, on this story later…
This was the old Standard 10 engine, progressively stretched to 1147cc for the Herald, then 1300 and finally 1500.
Is it known if the CG engine used in the Micra K11 was related to the MA engine used in the Micra K10 (as well as if any commonality exists between the CG and later CR engine used in the post-Renault takeover Micra K12)?
Another seemingly common conversion in the Midget was the Nissan A engine that was typically mated to a 5-speed Nissan 56-Series (non-overdrive) and 6o-Series gearboxes as used by RWD Sunnys from the B110 to B310.
From what I can work out, the bottom end of the GG is an evolved version of the MA’s, and crankshafts are theoretically interchangeable, but in practice there are incompatibility issues with ancillary drives. The cylinder heads are completely different.
The CR looks like a further evolution, eventually replaced by the three cylinder versions of the Alliance HR engines
Understand. Quite fascinating how the MA was in some respects a scaled down version of the Nissan E that itself was a major redesign of the Nissan A engine, which had similar features as the Ford Crossflow such as 8-ports and 5-main bearing crankshaft, etc.
If only BMC didn’t overcomplicate things and instead looked at Nissan as a more relatable example of conservatism done right in building upon existing ideas.
I remember seeing a Sprite at a Hillclimb with big wheel arch flares and a more modern 4-cyl, most likely Japanese although I can’t remember the details now (20yr later).
More recently there was a A-H Sprite powered by a Chrysler Hemi V8 road-tested on Youtube – worth a google!
It would appear the art never dies