The Lotus Sevens: The Real Most-Hackable Cars

In the late 1940s and early 1950s, Europe was still struggling to recover from the crippling after-effects of war. In Britain it is referred to as the “austerity period”, with food still rationed and in which “make do and mend” was very much the order of the day. The consumer boom of the late 1950s and 1960s was very far in the future, and if you were a hardware hacker your source materials were limited to whatever you could find from war surplus or whatever prewar junk might come your way. This was a time in which the majority of adults had recently returned from war service, during which they had acquired practical skills through the necessities of battle that they sought an outlet for in peacetime.

One field that benefited from this unexpected flowering of creativity was that of motor racing. Before the war it had been an exclusive pursuit, with bespoke cars at famous circuits like the banked track at Brooklands, in Surrey. In a reflection of the wider social changes that followed the war the motor racers of the post-war years came from humbler backgrounds, they raced homemade specials made from tired-out prewar motors on wartime airfield perimeter tracks like the one at Silverstone which still hosts Formula One racing today.

A typical Austin Seven Special. Probably a lot shinier than my dad's one. Barry Skeates [CC BY 2.0 ], via Wikimedia Commons.
A typical Austin Seven Special. Probably a lot shinier than my dad’s one. Barry Skeates [CC BY 2.0 ], via Wikimedia Commons.
My father raced an Austin-7-derived special during this period. Too young to have been a combatant, in the early 1950s he was an engineering apprentice at a large truck manufacturer. He relates tales of home-made gasflowed manifolds for the sidevalve 750cc Austin engine, and of wild and crazy cam profiles built up with weld, then ground down and hardened. Prewar Austins were plentiful and cheap, so many such vehicles were created.

Cars like the Austin 7 proved to be less than suitable as high-speed racers though: the original A-shaped chassis and suspension had been designed for the roads and speeds of the 1920s. The community of special car builders responded to this with their own chassis designs, and from their ranks came both the roots of today’s Formula One and British motor racing industry, and the modern kit car industry.

An early Lotus Seven. Thesupermat [CC BY-SA 3.0], via Wikimedia Commons.
An early Lotus Seven. Thesupermat [CC BY-SA 3.0], via Wikimedia Commons.
One name from that period which embodies both Formula One and kit cars is Lotus. Its founder, [Colin Chapman], produced a succession of racing specials from the late 1940s through to the early 1950s, and the company eventually became a manufacturer of production sports cars which were also sold as kits. Today, Lotus is a 21st-century manufacturer based in Norfolk and making cars at the forefront of technology, but back then they were something of a shoestring operation in a North London workshop. My father accompanied a friend to pick up his newly purchased Lotus Mk VI, and remembers seeing [Chapman] spreadeagled over the bonnet of a prototype Mk VIII covered in little bits of wool, being driven up and down the road so he could observe the turbulence over its bodywork.

The signature Lotus of this period is the Lotus 7. The running gear of a 1950s Ford Popular with its 1.1 litre sidevalve engine, placed in a minimalist two-seater, open-top space-frame chassis, with double-wishbone front suspension and a live rear axle. It was sold either pre-assembled or as a kit to avoid the purchase tax that was then applied to assembled cars, and it achieved significant success. Lotus continued making it in various versions with ever larger engines alongside their more modern cars until the 1970s, and when they ceased production the rights to its manufacture were bought by the Lotus dealer Caterham Cars. Caterham have built a very succesful business from their Sevens, and you can still buy one with very up-to-date running gear and suspension in a variety of models either pre-built or as a kit from them today.

Enough With The History, Take Me To The Cars!

Just one of Caterham's many takes on the Seven. Steve Marsh, Lotus 7 Club of Great Britain [CC-BY-SA-3.0], via Wikimedia Commons.
Just one of Caterham’s many takes on the Seven. Steve Marsh, Lotus 7 Club of Great Britain [CC-BY-SA-3.0], via Wikimedia Commons.
This history lesson is all very well, you might say, but what claim does a single small-production-run sports car have to being the most hackable car? After all, cars like the Volkswagen Beetle were made in the many millions, and we’ve already made the case for that model being the most hackable car. The answer comes not from the “official” Lotus and Caterham Sevens, despite their being as hackable as any other example, but from the many cars that were either inspired by the original design or are outright copies of it.

Since the 1970s an astonishing variety of manufacturers have produced unauthorised cars based on the Lotus Seven design, and in many cases their products are nearly indistinguishable from the real thing. However that alone is not yet enough to qualify these cars as the most hackable, for that we must look at the final source of their manufacture. This is a car simple enough that almost anyone able to weld and find the required donor parts can build one for themselves, and that is just what many enthusiasts have done over the last few decades. Helped along by the popularity of a Haynes manual describing the design of a Seven clone in huge detail, a cottage industry of suppliers has appeared, providing almost any of the required parts from the chassis downwards. The plans are readily available online to anyone prepared to search for them, and can be easily modified to an individual builder’s plan. So-called “Locosts” have appeared with an astonishing variety of engines and running gear, everything from small car engines to V8s and superbike units and many more. Among my friends I can number owners of Locosts with Ford, SEAT, and Honda units, for example. They are a very common sight on summer weekends, at least from where this in being written, less than a Seven’s tank range from Silverstone.

Just What Makes It So Hackable?

A Locost rolling chassis. Super-seven [Public domain], via Wikimedia Commons.
A Locost rolling chassis. Super-seven [Public domain], via Wikimedia Commons.
It’s worth a look at the car in a little more detail, to find out what makes it such a good platform, and for that it’s best to start with a reminder that this is a sports car stripped to such bare essentials that few other vehicles with steel frames weigh less. This means that as a driving machine, it can extract the most from the smallest of engines. A personal view is that it is best in its purest form: an engine whose power you have to work to release, mated with skinny tyres. And indeed Caterham’s current base model follows this formula with a little 3-cylinder Suzuki unit.

The chassis itself as described in the Haynes manual and other sources is a space frame welded from box section with a central transmission tunnel flanked by the two seats. Various modifications have been made to the basic design, including wider versions for more generously proportioned drivers, stiffer versions with more reinforcement, and rollover bars and cages for the racing versions.

The front suspension is a double wishbone, with verticals sourced from any of a number of possible donor cars and the wishbones themselves fabricated by the builder. There is considerable scope for a builder creating their own suspension geometry here, though personal observation of Locosts built by friends tells me that getting it right can be a lengthy process.

4637015778_7abc19b32c_zA Locost with a Toyota 1600 engine. Stefan Båging (CC BY-NC 2.0), via Flickr.
A Locost with a Toyota 1600 engine. Stefan Båging (CC BY-NC 2.0), via Flickr.

We’ve mentioned the breadth of engine choices already, but the transmission can come from almost any smaller inline-engine rear-wheel-drive donor vehicle. The archetype is the Ford Escort Mk1 and 2, however coincident with the popularity of Locosts, the supply of these cars dried up very quickly. More recent donors have been Mazda MX5s, or any of several small commercial vehicles.

At the rear, the original cars sported a live axle. Yet again the Escort units used to be a favourite but supplies have dried up, so alternatives have had to be found. Many designs have for example used independent suspension derived from Ford Sierra or Mazda MX5 parts.

So… When Are You Building Yours?

As you can see this is not only a design that facilitates modification to an individual builder’s specification, it is also one that is undergoing a process of continual development. It is still possible to make a car that resembles [Chapman]’s original, but the builder is not restricted to that choice. One thing is certain, [Chapman] himself would have definitely moved the design on over the decades.

If you are nominating the most hackable car, it does not have to be one that achieved a high production run, or even one that has the best overall design. Nobody is claiming that the Seven is the best car ever designed. Instead a car in which every aspect of its build can be modified at the maker’s discretion takes car hacking to entirely new heights, and in that the Seven delivers in spades. There is quite simply no other car design quite like it.

So there you have it, the Lotus Seven derivative is the world’s most hackable car. My garage is busy enough keeping a 1960 Triumph Herald on the road (incidentally a car whose front suspension carried Lotus to Formula One success), so when are you building yours?

Header image: AxelKing  [CC-BY-SA-3.0], via Wikimedia Commons.

64 thoughts on “The Lotus Sevens: The Real Most-Hackable Cars

    1. Or you could cheat slightly and buy one :-)
      Given they are never finished and always in a state of “upgrade”, it’s a lot easier to just leap to the tinkering stage and avoid all the frustration at having lots of bits of a car, taking up all the space of a car but not actually having a car that one can drive. It also makes a good way to work out what things you like, don’t like and what you would change “when you get time to build one yourself”

      Still, one day I might also build one all of my own (but, in the meantime, I can at least drive the one I’ve got).

      1. There’s nothing quite like building from scratch, but with the increasing tightness of legislation in the UK, it’s becoming less and less tempting. Much better to buy a basket-case that’s registered, and then ‘modify’ it as you wish.

        Electric se7ens seem unpopular, as they’re a bit too small to take a decent battery capacity – you’d be much better off with something like an MX-5.

        Also, don’t underestimate how invisible an electric se7en can be – I saw the Tiger one in ~2000, and the main complaint was that no-one saw you, and no-one heard you. Ally that with ~4s 0-60, and it’s asking for trouble.

  1. And if you are unlucky enough not to be able to afford a real Lotus/Caterham 7 or one of the many clones (or a scratch-built version) you can always buy the recently released LEGO version of the car… :)

  2. No mention of IVA or registation, which is the real nightmare with locosts in the UK where this article was thought of.
    Nor of, which has to be the most prevalent forum for it.

    I know the pain of the iva as I have a “incorrectly registered kitcar” as the dvla put it, still carrying the donor beetle identity and now its no longer titleable (mot’able) because the test stations refuse a 68 beetle based kitcar from being tested because it doesnt say “beetle special” in tiny writing on the v5.

    Really, 9/10th of car building is working out how to evade the dvla or spending countless hours shoving balls into shapes in bodywork on stuff to make sure it conforms to the draconian requirements. Really, you can take currently legally registered production cars and they fail the iva test, let alone a classic car.
    The uk may have been a car builders paradise in days gone by, but thats long gone. Now dvla employ people to scour facebook and public posts for evidence of modified vehicles and pull them in for “identity checks” if they dont look original. Hot rodding is also under the cosh as of late too. You might argue its about safety, but the accident rate of modified and homebuilt vehicles is staggeringly low compared to producton vehicles, maybe the owners dont want to waste all that work and effort?

    1. SVA was moaned about a lot at the time, though it was just a case of reading the rules and not being completely insane to get a car through (I did 2). On registration, one got an age-related plate (single donor), and one got a Q-plate (had to prove date of engine for emissions/tax).

      With IVA and the clampdown on the pre-SVA habit of keeping the donor identity, it makes things a lot more difficult to both construct from scratch, and buy a basket-case and ‘modify’ it.

      I’ll not be selling my Q-plated, non-emissions-tested car until hell freezes over…

    2. If you think we’ve got it bad with the IVA etc. just try talking to petrolheads from literally anywhere else in Europe, most countries you’d be called a dangerous madman just for changing the alloy wheels on your car, let alone building an entire car in a shed and expecting to be allowed to drive it on the public highway.

      In short, don’t kick up too much about the IVA, if anyone looked too closely it might get scrapped altogether or replaced with something far worse. Most of it is actually not too hard, and thousands of people have gotten kit-cars through so the knowledge is out there.

    3. I had to help a friend with a Cobra replica a few years ago, had to play the IVA test game.
      It’s such a joke of a situation, the kit supplier even lends out a box of goodies that meet the IVA requirements, you fit them, pass the IVA test, take them off and refit all the proper period parts and send the parts box back so they can give it to the next customer to get through the test.

      1. Thats great, but my kitcar (A Nova/Sterling) has headlights that cannot be made above the minimum headlight requirement the IVA imposes on the kitbuilder. I can probably fudge it by welding/adjusting the front suspension, fitting larger diameter wheels both ends and adjusting the wheel wells to accomodate, and plus a multitude of other changes. And then after cutting it all out and putting it back to how it was because the extra ride height will affect stability.
        All for a car thats been on the road and passing mot’s from well before sva was even introduced, of which there were thousands in use on UK roads at various points.
        My other issue is its a moving target, I have a friend who started building under sva, and now has to redo lots for iva. Probably when he’s finished a multi year revamp it’ll be whatever replaces it next.
        Lets not even begin to discuss hotrods and the recent zealous enforcement of the 8 point rule. Or say a rebodied scimitar and you trim the rear bumper outriggers where they stick out and form a risk for other vehicles and suddenly youve modified the chassis and have to go for IVA. The pendulum has swung very very far the other way in a short space of time.
        I sent my logbook in for change of address on another of my vehicles and it got pulled in for a “automatically selected” vlc identity check, had to take photographs of the chassis numbers, the engine + its numbers, and the major components of the vehicle. Thats 40 years old and 100% original, but say it was the likes of a old austin special hillclimber, that’d be going for IVA too.
        I watch roadkill occasionally on youtube, and the requirements seem so lax in the states its unreal. Its almost enough to make me want to pack my machine shop in a few containers and head there at times.

    4. I don’t quite agree with this view of the test. Yes it’s stringent, but if you read its rules they largely describe a common-sense and safe way to make a car. As you might imagine I have more than one firend who has put a car through, and their experience has been that if you built to pass from the start you shouldn’t have too many problems.

      (The “incorrectly registered kitcar” thing is another matter, and agreed, a huge PITA. I’m talking about from-scratch builds.)

      1. “So when are you building your car”, the answer should probably have been “after I’ve spent months reading the small print on the regs and researching the legal side” as thats by far the most fraught with potholes part of things. If you don’t build explicitly for the regs, or you start with something thats not current in the regs and has incorrect registration (as pretty much most kit, hotrod and locost builds on ebay seem to be) your in for a world of pain.

        Really, I’m frustrated with the dvla and the periodic changing of the goalposts, mostly from years of having to deal with them on modified car stuff & not to put a damper on things but I think you should have forearmed people about the same.

        1. Swear I know your name somewhere MrFluffy. As for the testing, i’m in two minds, i’ve seen a lot of half assed work on standard cars that frankly makes you wince knowing it’s going out on the road, complete with the knob socket who’s done it behind the wheel, and it goes through. On the other hand i want to see great creations, shed built wonders getting out there, and i don’t want them being constricted and stifled, but there has to be some.. measured responsibility..

          Mr Biscuit

        2. It’s true I’m talking about from-scratch builds rather than mods of existing cars, as that’s what I’ve seen my friends do. Understood, the complex mire of dealing with a modification is very different from making a regs-compliant Seven from first principles.

          But yes. I’ve sat down with more than one friend and read the regs, and though some parts are a PITA they are not impossible to satisfy.

          I’m old enough to remember the days before the SVA/IVA. Given the downright awful stuff that people were taking on the road in those days having merely put it through on the nod with a friendly MOT man, I’m not sorry at all we have the test.

          As to your point about forewarning I considered it, but remember the majority of readers here are not from the UK, so a lengthy passage about the IVA would be meaningless to them.

          1. Aware IVA will mean little to lots of the audience, but each person will have their own local version of the legislation octopus to deal with and getting aquainted with that in advance has to be the #1 task around building your own car.
            The aussies have tech inspection, the germans have the TUV process, the french used to have the carte grise originale but that stopped about 10 years ago and now have something that I’m still trying to detail but apparently costs 10k per car to do though nobody really knows so they just use pre 50’s registrations as there’s no records from before that date, the spanish have iva. As I alluded to above, the US legislation seems amazingly slack or at least thats the impression I get from speaking with other builders and shows like roadkill and some of what turns up at shows and meets. But if you do your homework early enough…

            Yes I remember pre sva days. I was invovled with modified and self built stuff back then too. Some of the kitcar stuff was chickenwire and grp filler shocking in the early days but then so were a lot of standard original cars. I’ve seen far worse on production cars that have passed a mot and been deemed roadworthy by someone else with pop riveted on repair plates that should have been seam welded covered by lashings of underseal (I used to work in a mot bay once upon a time…) to get out of shape about the state of loved and cherished modified cars.

          2. I neeearly bought me a pile of octopus wrestling a couple of years ago. 80s replica with a minor engine fire, but it had rendered the title unfixable. … and a separate frame turned up at the same time… but it turned out the frame was an abandoned shop project, that hadn’t had a number registered, and there was no records of material purchase etc to help with ownership… also got pics of it and it was terribad fab work, twisted with awful welds… anyhoo, could have got a really cheap track car, but rebuilding it for road would have been paperwork nightmare.

          3. Before you pack up and move to the states to avoid the IVA, make sure you are not headed to California. Most rights infringing draconian legislation starts there and spreads east. I’m sure it is not quite the nanny state as where you are, but it is not far behind and is trying to catch up.

  3. So, the Lotus 7 is an iconic British car, and the headline photo is of a LHD replica – I think a Dax Rush.

    Not that there’s anything wrong with the Dax – it just needs a V8 to be serious :)

    1. My mate changed his Land Rover from fuel-injected to carburetted in about an hour in his garage. Something went wrong and he didn’t have the parts to fix the fuel injected bit, so put on a new manifold and the other relevant bits. Then drove us a couple of hundred miles down to meet our friend. I was amazed at the time. He was formerly an engineer on boats, but came back to land cos you don’t meet many women in the middle of the ocean.

      A Land Rover must be in the running for hackable car. There must be every mod imaginable for a car, out there on a Landie somewhere. And they just don’t die!

        1. I’ve seen people change an engine head on a Caterham K-series (overhead twin-cam interference engine, so careful timing needed) in an Austrian hotel car park with no specialist tools, after fetching the head from Germany the previous day…

          1. Timing isn’t exactly rocket surgery though, it’s mostly just making sure the dots/arrows line up.

            Depends what you’d call a specialist tool, but I hope at least a torque wrench was involved.

          2. As a owner of a MGF (also very hackable!) I can say that this is something Rover has done very right. Both with the K-type engine and with the MGF as a car. There are not many special tools required to do any work. Ok, the engine is not very accessible in an MGF but still quite servicable. And it runs very well.

  4. Go to any vintage race and you find these little lotus 7 cars all over. After the proper tweaks and cheats they can get around a track pretty good. Don’t be mislead though. They are not fast cars. They are momentum cars that bring out a drivers skils. That is why they are popular with first time racers and clubs. They are also perfect examples of how it can be more fun to drive a slow car at it’s limit than a fast car normally. All in the sense of speed.

  5. Another vote for Mazda Miata MX-5. You can electrify it, put a V8 in if you must. Stock handling is good and for a little bit of cash it can be made awesome in performance and handling.

    Watch this about the Miata. if you are impatient, jump to 14 minutes:

    Kit ->

    To be very honest it is just as fun as my Lotus Exige S. It may not draw as much attention as the Lotus, but the Miata is easier to get in and out of after a meal. Anyone who says the Miata is a girls car has never driven one.
    Sorry for the hijacking intermission.

    1. just take the roof off the exige s

      while i love the miata, and have had a few of them in the past, the exige S is a lot more fun car for me personally, the miata is easier to throw around with less consquences but when you get into the exige’s best areas when it corners almost like its on rails makes smiles all around, especially when you add a little more power too it.

      though i’d still have a monster miata, they both great cars , and the miata does take design cues from the earlier elan

      shame what chapman ended up deciding to do, but lotus is still a fantastic car maker and still shoestring

      the m100 is also a fun car to drive

      be seeing you.

  6. While interesting and hackable, it lacks all the safety design and technology improvements we’ve made over the last 60 years. Frankly, just hearing about what used to happen before collapsable steering wheels is enough to make me avoid this.

    1. Collapsible columns are a SVA/IVA requirement iirc. But you’ll also find that most people fit 4 or 6 point harnesses, so you don’t get thrown as much as with a lap/diagonal.

      More concerning imo, is the exposure of the fuel tank (hanging out the back), and the lack of side protection (though it’s still better than some backboned designs (eg Lotus Elan, TVR etc).

      As for safety in general – yes, you’re a vulnerable road user, and should always bear that in mind. However, having seen a few Caterhams that have had accidents (one being a ~50mph head-on, resulting in a broken wrist), it’s very impressive how a spaceframe chassis can distribute the impact.

    2. “…enough to make me avoid this.” Is exactly how it should be. We should be allowed to assume our own risks instead of having it decided what is best for us by some third party authority. We all certainly cannot agree on what is dangerous. Remember when Professor David Nutt was asked to resign for comparing the risks of equestrian activity with ecstasy drug use? Within personal choice lies freedom. There are counter arguments, but keep in mind, there is no perfect solution. I would rather the choice be my own.

  7. A normal V8 in this car would be nice, but I think it would throw off the weight distribution depending on the V8 you use of course. Instead a few people have successfully added a Hartley V8 to this car. A Hartley V8 is essentially two Suzuki Hayabusa engine combined to create now wicked compact high revving engine that make a Lotus Seven go plaid! (Spaceballs reference).

    1. I have to say, I’m not a fan of the bike engined Sevens, nor of the V8 ones. In my opinion they risk making barely controllable track toys whose potential can rarely safely or legally be unleashed on the road.

      Quite a few years ago the British racing driver and TV presenter Tiff Needell did a retrospective review of the Morris Minor, which he nominated as one of his all-time favourite cars. For those not familiar with the Minor it’s the iconic 40s-to-60s era British small car, 1 litre engine and a live axle. He rated the Minor not for its lack of power but for what it could do with the power mated with skinny crossplies. It’s an amazing amount of fun to drive, because it slides comically easily and is also extremely easy to control when it’s doing it. A Minor on extreme twisties in the hands of someone who knows what they are doing can show up garage jewellery supercars, I’ve seen it done and it’s highly amusing to watch.

      That’s why for me the Seven is best at its purest, with a normal small car engine with more power than that weedy Ford Pop sidevalve, and skinny tyres. I care very little for 0 to 60s or straight line speeds, for me the essence of driving is having fun on a twisty B road when there’s not much traffic.

      But that’s kinda the point I was trying to make in the article, here’s a platform that can satisfy all tastes.

      1. Rover V8 in a 750kg Se7en gives ~330bhp/ton, which is about the same as a 165bhp (ie mildly tuned K-series) stripped out Caterham @500kg. It’s completely controllable, relaxed on the road when cruising (~2100rpm @70mph), but drop a cog and it’ll go like stink.

        Downside is that it drinks like a fish…

  8. I have just finished helping a friend build a Locost here in California using Miata running gear. It is a beautiful machine and a whole lot of fun to drive. I would love to build an electric version but the main issue is the weight of the batteries. That is proportionately more for such lightweight cars and, being low to the ground, there is less room underneath. Maybe with a rear mounted motor the batteries could be under the hood but that may put the weight a little high and forward. Any thoughts?

      1. Is funny because he says he’s a free man but he’s been gassed, taken to a remote island imprisoned and given the number 6 and is funny because he drives a Se7en… but at least he had the satisfaction of telling them where to stick it ….

        Yah I know that’s all in the joke, but I’m letting everyone under 40 and unBritish catch up.

    1. By the time you made room for it, it would look like a custom pulling tractor.

      Though I would think one of the VW diesels would almost approach sensible. Though for drivetrain maybe starting with a 190D makes more sense.

    2. Other than to be obnoxious “rolling coal” I can’t possibly fathom a single reason anyone would want to do this? A 4bt engine alone weighs 7-800 pounds and produces 105hp/265tq, which is almost what an entire running driving Lotus Se7en weighed.

      Conversely, my mx5’s 1.8 turbo engine and transmission weigh roughly 360 pounds, makes 300whp/250tq. Not enough power? An LS3/575 + T56 transmission is 620 pounds and makes 525hp/486tq. It should be noted, my mx5 weighed in at 2400 pounds and can easily shuffle down a quarter mile track in under 12 seconds.

  9. How does a car like this work in the U.S.?

    VIN and registration would be easy. But smog? When catalytic converter was ripped out, it took threes new cats and as many smog tests in order to pass smog without hassle because my state kept changing the laws. What happens with these type of cars with borrowed engines?

    1. sometimes they use a vin number from an earlier car (with some parts), so they can bypass certain laws, 1976 and before

      the normal way is just to have a modern engine system that passes smog and run it through the inspection, or buy a kit car that is designed to pass emissions

    2. It depends on the state and city/county. In many cases, they are registered as a 60’s Lotus Seven with a new vin provided by the DMV, so the emissions requirements would need to meet the era of the car.

      In some cases, if you use an engine newer than the emissions cutoff for the region, you have to incorporate ALL of the emissions controls for that engine into your design. This is especially true in California, unless you get an SB100 certificate via lottery and can title and register it as a replica or kitcar.

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