Thor’s Hammer: <br/>The MG GT3’s Accelerated Evolution
Biomech Under The Bonnet

I first featured Jason Shalders and his incredible MG project back last September, following a fortuitous meeting at the Autosport International show at the beginning of that year. His seemingly outrageous plan: to take a classic British sportscar from 1966 and to build a street-legal GT3-spec racer – one that could grab the Nürburgring lap record for street cars. A completely bespoke build, undertaken by a small and committed team, but spearheaded by Jason’s unwavering commitment and passion for the plan.


Six months on and the progress is suitably impressive. The car has been transformed visually, with the almost-complete body panels giving us a proper idea of how the car will sit: low and squat on those enormous O.Z. Racing rims. But it’s up front that I’ll be taking a closer look at in this update – the part of the project closest to Jason’s heart.


Whilst build specialists Chris Isaac and Jedd Guy concentrate on the chassis, body and dynamics, Jason has been building up the brutal package that will become the thumping heart of the MG.


I have to warn you – if you’re an engine fan then you might want to be sitting down for the next five minutes. This hand-crafted engine is a work of art. Now it’s ready to spread its wings.


The inspiration for the configuration of Jason’s V8 comes from Lotus’s own still-born 909 engine project, which was the company’s first attempt at a V8 in the 1980s. The combination of two incline, inline four-cylinders into a classic V8 was created for the still-born Lotus Etna concept car, but then dropped until the development of the 918 for the Esprit the following decade.


There aren’t 909 engines lying around to use, so Jason went with what he knew – the 4-litre Rover Thor block. To that he’d meld two high performance Lotus four-cylinder heads with completely different bolt patterns. And then bolt on a pair of turbos. That’s when the madness started – but it’s a very infectious madness…


So here we are – this is how far Jason has got, with the finish line for the project the start line of the Nürburgring. It’s the result of seven years of blood and sweat. The task of making those iconic Lotus heads work – and not just work, but work in the most extreme conditions – with its unwilling Rover bride can’t be underestimated.


At the beginning of this project, many years back, Jason started with the obvious thing: getting the four-cylinder Lotus heads to actually fit the Rover V8 block, with their completely disparate bolt patterns. Like a surgeon, the only way to find out how something works is to get your hands dirty. After a lot of hard, physical graft, Jason ended up with a stack of chopped up blocks and heads lying about – the detritus of the many experiments that led to the final Eureka moment.

With the optimal solution in mind, he machined out slots to get down to the block’s original holes, then built them back up with the extra width for the new heads, preheating as he went to maintain integrity.


Of course, that doesn’t magically make the two things work together – especially when you remember that one of the heads has been flipped around 180 degrees. The unholy matrimony meant crafting new waterways and looking at all the other important things like oil drain-backs.


Thor might have been the name of the engine, but even Thor needs some reinforcement from time to time.

The standard Rover cast block came cross-bolted and was prone to fractures from the block flexing, not helped by caps that could not only be pushed down by the crank but also move laterally. Jason has fabricated his own custom billet steel main caps, pinned and cross-bolted to counter any vibrations or harmonics that might be caused at the high revs they’re expecting.


New long studs protrude from the base, which will join to a new billet dry sump. The entire collection will then be mounted to the pan ring around the outside of the block and pulled in tight to make one big structural unit. With the power numbers the team are working to, they can’t afford any movement.


Jason’s added a massive amount of reinforcement across the centre of the block, where originally there were just three puny ribs trying to stop the block from punching itself apart and creating two messy inline fours. He’s added significant structural webs, which in itself was no easy task.

Even with meticulous preparation prior to the reinforcement, the nature of the aluminium block meant that it started shifting around in every direction as the welding was applied. Subsequently, there has to be some major machining to bring it all back to dimensionally and physically squared-up proportions.


The first major modification on Jason’s list once the heads were addressed was to sort out the oil supply to the main crank, that gets fed through the pair of galleries in the block. The new overhead cam setup meant that the original followers, pushrod and rockers were redundant – but removing them left gaping holes on the top of the block.


They couldn’t just be welded shut, as that would interfere with the oil galleries, so Jason crafted an elegant solution: a set of two-piece aluminium follower plugs with wasted stems that push in from both sides, cleanly sealing the block without affecting the oil flow.

As with so many parts on this complex engine, this simple and elegant solution came hard. Initial solutions tore their O-rings off on installation or fouled the passages. Create, test, iterate; Jason’s mantra comes from Eddison, inventor of the light bulb. “I have not failed. I’ve just found 10,000 ways that won’t work.”


Along with the dedication to quality on the build, Jason also wants to be able to make the modifications commercially available once the car is finished. The MG is a technology testbed, and having that commercial goal ensures that the bar is always set high. ‘Just about’ isn’t good enough – everything has to be perfect.


With the core engine at a good stage, it was the time to start looking at the surrounding ancillaries, the manifolds and inlets. Getting these parts in place would allow Chris to build the car up knowing the position of the engine’s main components – they wanted an engine that worked for the car, not for the dyno room. It also meant that, like the car, the engine is truly showing its potential character.


There’s just nothing simple when you’ve taken on this kind of project, using proven but old tech. It’s like the trying to fit imperial to metric thing, where almost nothing fits first time. Case in point: the manifolds. The ports were oval, so had to be taken to the round tubes, 316 stainless steel flanges were laser cut, created by Chris and Jedd, to connect to the Inconel system.


Everything has been specified and designed around endurance – this car is true to its principal of the classic trackday ethos, drive to the track, thrash it around, drive home.


Speed and performance are matched by a concentration on safety. Heat flashpoints on the car use appropriate materials, with the team cognisant that even hot gasses from cracked exhausts could trigger major problems – the Inconel exhausts show the pragmatic approach.

Bringing The Hammer Down

Boxes are turning up every day at Chris Isaac’s workshop – the turbos some of the latest goodies to arrive on the day of my visit. Owen Developments have supplied the twin GT35-82 HTA turbos, one of many companies who have stepped up with both technical and product support. It’s that kind of project: you can’t help but see this car and then get swept along with it.


If the spread turbos are things of beauty, then they’re only matched by the magnificence of the Jenvey injectors that cap the whole structure.


Jason knew he wanted a multi-plate inlet, understanding it should drive better and give the pilot more feel – of particular importance when you’re setting your sights on the Norschleife. He calculated the distances for the inlet manifold, using MDF to rapid prototype templates, then worked with the team at Jenvey to design and create the finished units.


Although billet aluminium and steel is used extensively, the cast manifolds met the other criteria for the MG: to retain a classic feel across the car. They look stunning, and again they’re an aesthetic solution to the constant challenge of this engine melange.


Working through options like reducing the height by running lower double injectors or port injectors from the rear, Jason concentrated on getting injectors right into the bell mouth, firing into the trumpets. This way, slight evaporation and expansion of fuel would also create a cooler air charge.


The inlets couldn’t run straight as they’d clash (the 909’s engine ran in a cat’s cradle across the top of the engine, a bit like a Corvette’s), plus again needed to go from round to oval. So the 20-degree curve was introduced to bring them to the vertical – which just adds to the pleasing aesthetic.

With the heads designed to be run slanted over, with carbs also angled, Jason wanted to use individual throttle bodies, with double injectors for cooling, two per cylinder for the ignition stages.


Technology has snuck in here though. Off to one side is the fly-by-wire throttle system which will link to the seamless shift, paddle-shift-controlled gearbox; anti-lag comes as an additional benefit.


The idea is for the engine to rev fast and freely up and down the range, almost like a bike engine, so Farndon have created a compact flywheel to the team’s design, backed up with a five-inch clutch plate.

The liners were another present just unwrapped, delivered from Westwood Cylinders, and should now have been dropped in. As is the norm for this build, they were slight variations on the stock item, created in partnership between Jason’s team and the company.


Harmonics dampening across the rev band will addressed care of this substantial Fluidampr viscous damper unit.


The beautiful Arias piston heads (yes, modified specifically for the MG) are covered in a protective ceramic top application, with a Moly coating around them to prevent wear on the bores. They come with standard twin rings and oil scrapers, plus fully floating gudgeon pins on the inside.


The MG’s ECU is still at the discussion stage: it’s a big decision as it’ll need to work with everything else on the car. The team want to avoid duplication where possible, so ideally sensors will be shared between systems – the car will be laden with a full suite of data-gathering and monitoring sensors.


The car will end up with three wiring looms: one for road use (indicators and so on), one for the engine and one for the gearbox. It’ll make changing things easier – which is especially important as Jason is also working on the four-cylinder turbo Lotus engine option.


Based on the Lotus 912, that’s going to be a 650hp screamer. Jenvey are designing bespoke manifolds for it which will work on the horizontal plane rather than the vertical of the V8. But that’s another story in itself!


Jason’s next big project is working on the front cover, designing the layout of all the idlers and pulleys and finalising the dry sump. Wide belts will be used, plus the offset of the engine has to be compensated for. Front pulleys will drive the odd numbers and rear the evens.

Possessed By The Alien

When it gets to the body, the talk is always about air. You get the feeling that Jason and Chris aren’t talking about physical steel and filler, but see the MG as an ephemeral entity, the movement of air and its effect.


From the last time I visited the shop there’s been dramatic progress. The old MG is still distinctly there, but now it’s buried under a mass of battle armour, stretched, widened, flattened. Paint the panels, pop some glass in and you feel the car would just drive itself off into the distance. Of course, there’s still a way to go, but you get the impression that they’re onto the detailing.


Chris was working on the rear tubs, which will be sealed except for the protrusion of the suspension arms. This will protect the inside of the units, and once the charge coolers are in place with their protective grilles control the smooth movement of air up and over the rear arches.


Each area of the car is treated this way, with the aim of creating enclosed packaged spaces that protect their respective components.


The final lines are being smoothed off, then the formers will be sent off to Ryan Ennion at SP Automotive, who’s responsible for all the bodywork. Once everything is signed off, the whole car will be handed over for the final phase of bodywork prep, initially in fibreglass but with the hope of moving to carbon fibre in the not too distant future.


Starting at the front, the massively aggressive splitter dominates the nose. It’s split into sections, so individual parts can be easily swapped when trying out aero configurations. The front air ducts feed the ITG filters, which in turn push high pressure air straight to the turbos.


Behind is the ducting and aluminium Proalloy radiator, a bespoke unit as with so many other components, designed expressly for the MG’s cooling requirements. It’ll be overcooled for the four-cylinder Lotus engine option, but in that case carbon blanking will be used.


Hot air is ducted out over the frankly epic bonnet. With the panel on, it’s like the Alien has pounced onto the nose and buried itself deep down.


The result of numerous iterations, always trying to stay true to the styling spirit of the MG within, this version pushed the vents back slightly, which gave an advantage to the speed of the airflow as well as helping thrown the air up well clear of the engine bay.


There’s space at either end of the MG’s old grille which could be used for brake cooling, plus they may take more air from the underfloor to help cool the turbos. The clear expectation is that with everything going on underneath the bonnet, it’s going to be a potentially volcanic place to be.


Despite the bulge, visibility for the driver is going to be surprisingly good. Race driver Oli Webb, who will be aiming the MG at the ’Ring come the end of the year, reported that sight lines were all fine and that the important bits were in vision. Who cares about what’s behind you?…


There’s still a long list of design challenges ahead – things like the header tank, batteries, wiring, reservoirs, pipe work, alternator, starter motor and so on. But it’s not endless, which must be pretty reassuring for Jason and the team.


A lot is about packaging, like does the pedal box go high or low, which will affect the steering column, which in turn affects the manifolds. But this interconnection helps in a way, as each step can tick off multiple questions.


The big question remains though. How will it perform? That aim of beating the cream of the hypercar world in what they want to claim as their own backyard is crazy – a bit like the idea of jamming two completely different engines together. But the latter will work… so why not the former?


Jason’s dedication and passion hasn’t been exhausted – if anything he’s already finding new things to add to the project – and this 50-year-old MG looks almost ready for battle. Later this year we’ll get the answer. I think they’ll be a lot of people in a lot of boardrooms who are getting a little anxious…

Jonathan Moore
Instagram: speedhunters_jonathan



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This is amazing.


sweet... I wish that hood looked a bit different, couldn't they drop the engine just behind the driver seat, there's no lack of room there for sure, and would get better balance and epicness for bonus

Nicholas J OGara

Lord...for a proper Speedhunters feature!
Mr. Moore, you restore my faith in SH. Great coverage and great shots, reminds me of the old articles I enjoyed from Paddy McAwesome. That third shot is awesome, the anatomy of the powerplant; It somewhat reminds me of an old picture showing of an F40 powerplant.
John, Thanks again!


just incredible.


Clicked this because the preview picture looked cool. Casually scrolled through the pictures without reading, then i saw all the welds and weird stuff on the motor and got curious. Started reading from the beginning and I didn't stop until the end. Very well written.
Now: holy shit! a custom build v8 from two separate inline fours, that takes some insane knowledge; As well as making your own water ports in the head. The crankshaft alone is worth more in time and money than any of the cars i've built.
I'll be reading the previous MGB article as well as any future ones. Thanks for the awesome story Jonathan Moore!


Side view with front fenders please!!!!!


All that in 6 months?! *faints*
(A voice rings, saying "Speak to Me" as he gives me a chocolate milk drink.)
Ok. I'm alright now. Man.

So I'm gonna see this in the same place as Mr. Glickenhaus' car, right?


Jesus H Christ. This is mental. Massive, massive respect to everyone involved.
This is proper Speedhunting.


Damn that thing is insane, I was just thinking of this build too!
That engine is a masterpiece! 
Can't wait until the finished product and fire up.


I want to hear this.


Actually the Rover engine used is a V8, and the heads are what are from an inline four. Maybe not as hard as making an eight cylinder from a pairs of fours, but close. An impressive build either way.


Mahfoodh I don't know if you realize just how small an MGB GT is. It's a tiny car! Look at this picture for reference: 

Of course, the one in the article looks bigger due to the widening, but it's still a short car :)


Can't wait to see this thing in action! Not to mention the engine.. Holy shit. I've got a standard '66 GT in almost the exact same yellow color, so I may be biased (probably..), but this is the coolest project ever.


Trying to figure out why they went the route of modifying an existing block rather than using the rover block as a reference and CAD designed a new one to suit, but more respect to them.

Awesome build, I just hope to good they have blueprints made of that engine before they fire it up.


British engineering at it's best. Two turbo'd bike engines mated together might have been an easier engine solution with a similar result, but fair play for not compromising regardless of the difficulty. Looking forward to seeing this moving under it's own combustion.

Any idea on what the final kerb weight will be?


wow, this guy reminds me of Mickey Thompson. No reason this should work but if it does he will be a genius.


I love this thing! Absolute EPIC fabrication!


Mahfoodh There is not a lot of room back there. Not at all. As an actual owner of numerous MGs, including a GT, even a transverse package would be a very tight fit. Do not let the existence of a rear seat fool you. My infant daughter would struggle for leg room back there. I love this thing. All except for the hood/ bonnet. It looks like a rolling forward visibility nightmare. But, function > form I guess. Keep the updates coming on this. I drew something very similar out in high school.


this thing is already beautiful


In my opinion, he sould keep it like this.



I agree.  This seems like a bad way to go for modifying an engine block.  A billet aluminum one could have been CAD designed a milled without going through the stress of welding and heating, and modifying the block.  What happens if one thing is off on the block or fractures a cooling jacket during it's first heat cycle?

Doing a full billet block would have also eliminated the need for modifying a bell housing bracket of the transmission.

But good on them for sticking with it to make it work.  I wish them the best.


Incredible, the guys like a car savont.




Am I the only one feeling a bit of a TVR Speed 12 vibe?


@Lynk @Kenny 
Thanks for the comments guys... The simply reasoning is based on finding out what you have to do to get the lotus heads on to a Rover.. To see what you have to do to get it to work.. By making a billet block, it's no longer a Rover block.. Thats the simple reason.. This ebngine has been developed over many years, with some of the best in the business.. 
As for welding blocks, that has been done in all sorts of racing for years, as long as you follow some basic principals! Early 6R4's chopped a cylinder out an welded it back up! The TVR Speed 12 had a hand fabricated block. Dragracing regularly breaks blocks and welds them together.
This is a prototype engine, and thus, this is the way we have chosen to develop it. It's far far cheaper than designing a 3D CAD model and then, writing the CNC files, finally machining out of billet.
You could try casting, but as an example, the intial pattern and two prototypes for the inlets , without all of the initial desgin, or testing will cost you upwards of £6k! so imagine how much bigger stuff costs!


Very pretty build indeed. However, Anti lag is not neccecery or even useful on the track, it will just make the car more of a handful to drive as when pedal goes down the car will just go off on a smash, which would make smooth cornering very hard.


My mind is literally blown. I cannot even take this all in. Its pure uncensored petrolhead porn at its finest. That engine is a sexy work of art from the intake runners down to the turbos. 
Also, this car should go to Gatebil.


Oh yeah! This is what it's all about. So much to process, but what's stands out to me immediately is how good the body work is. Although very much WIP, it looks made by folk who really know what they're doing. 

So inspiring! Congrats to everyone involved so far. Can't wait to see this continue to develop further. This may be one of the best builds in the world at the moment. Amirite?!


Since this is a prototype engine, what is the plan when it's time to make it commercially available? I'm sure you won't want to be welding and modifying Rover blocks every time a customer orders one.
Amazing amazing build. Can't wait to see it completed.


Great pictures, fantastic build. It would have been a hat trick with me saying fantastic story as well... It would have been except for the lack of editing. Who does not know how to spell "Thomas Edison". All in all well done, keep up the good work and spell check is your friend....


I have to echo sentiments that the engine, amongst other things, has been built the "hard way".
That says A LOT about how CRAZY the man is and the machine will be.
I salute you, sirs.


Oh, I almost forgot:
that is all.


Is that the same pedal box as the SH Golf?


If money allows, I plan to do the same thing to a clapped-out Citroen DS one day.


Man, that hood is ugly. Great car indeed


i asked for this on the vw project post thanks guys !


MilesHayler Yes, its the same great OBP pedal assembly.. We are upgrading to the Billet V3 version when it's avaiable..


xrockonx We are currentlly maiing the new heads to fit on the rover V8, they should be avaiable leter this year..


@I Have No Name Now that would be AWESOME. Ha, a GT3 DS! Amazing idea.


@zz I think this car is going to end up going to a *lot* of places... :)


QD Never a bad thing – that was also a monster!


Jonathan Moore QD With a hand fabricated and welded block!


@Tom It should be around the 950 kgs... Fingers Crossed!


They certainly look solid and cool!


alex jonson a well set up ALS system can just be used to aid in throttle response! and will not turn the throttle in an on/off-switch!
ALS levels can even be changed in multiple settings to suit the track conditions, driver preference. As seen on modern WRC cars.


Impressive! They could have a visibility problem at the Nürburgring with that British bonnet!


I would never want to own it yet love it at the same time.


saw this at Autosport! its insane looking at this in person!
Would be popping up next year all done??!


The car is awesome, nice job. 
I'm interested in this car, so I did some modeling work in 3dsmax. Here's the link .The original model is from Forza4.


Hi there, that looks amazing! Wouldn't it be good if we could get the car in to a Game!


Kind of a Frankenstein creation, IMHO. I enjoy the esthetics of most SH feature cars, but the required big bump in the middle of this car's hood rubs me the wrong way.
That said, if the creators can figure out the engineering and make the car run like hell, then more power to them!


I've got the rover block where do I find the lotus heads?


Sometimes, just sometimes, ya gotta stand back and really look at what you're trying to do and ask yourself, "is it worth it and am I overthinking the problem".


wangtaojava Render it!  If you can't use Vray I'll have a go..




Well. I sure hope it works out for them. My version with the suspension and driveline out of a '92 5.0 Mustang is moving along a lot faster but probably won't break the Nurburgring record.


That's no a piece of art, it's a piece of SHIT.  I bet that thing lasts 2 MINUTES before blowing up!!!!!!!!!


That's not a piece of Art, it's a piece of SHIT.  I bet that thing lasts 2 minutes before it blows itself to pieces!!!!


the car was very good 
really really like to see the car that shiny new car fits like made ​​for walking trailsthe car was very good" rel="dofollow" target="_blank"> and very fast" rel="dofollow" target="_blank"> mix of colors" rel="dofollow" target="_blank"> from which to" rel="dofollow" target="_blank"> make want pobud see hatnya" rel="dofollow" target="_blank"> kecepatanya" rel="dofollow" target="_blank"> was very nice ," rel="dofollow" target="_blank">  suitable for a "" rel="dofollow" target="_blank"> sharp bend or not sharp I guess motorists like this is" very skilled in the speed I hope I can membilinya someday will whether there are new cars are better I" rel="dofollow" target="_blank"> 'll wait for it , with a stylish car classic" rel="dofollow" target="_blank"> style I" rel="dofollow" target="_blank"> also like" rel="dofollow" target="_blank"> to see would be whether there is a" rel="dofollow" target="_blank"> car that is as fast and forius like in the " movie , the car very good car designed a way apparently hopefully there will be new cars more good and the price is quite pantastis then chances are I can membilinya the same as you have at this time




What is that transmission?


I'm not gonna break any records but if the test drive today is any indication then I may just brown my shorts !  Take a look at Youtube and Thors' Tackhammer. There are 3 parts to date.