PH Revisit: Behind the scenes at Retropower


Greetham Imp Assembly
It's fair to say that Greetham can't really hold its own when compared to some of its better known contemporaries, 60s tuners offered plenty of fast road packages and go-faster kits for would be Jimmy Clarks, but that doesn't mean that its offerings were any less effective. Based in Chesterfield, Greetham offered a series of performance upgrades for the Hillman Imp, and it's one of these incredibly cool but equally rare cars that Retropower is in the closing stages of building.

"The idea of tackling something like a Greetham Imp was an attractive one for any number of reasons, not least its place in the history of the British tuner landscape, and also because it's such a rare car." explains Callum.


Dropped off as a bare shell last year, the Imp has since evolved into a light restomod project, with a litany of custom body and suspension tweaks. Among the most obvious, bar the coat of Vauxhall 'Sunny Melon' paint, is the revised rear end and 'boot' panel, a fixed part of the shell in regular Imps. Retropower have redesigned this so that it is a separate skin, with an equally custom engine brace to better locate the manic 1,200cc engine. This intersects with other, similarly structural braces located elsewhere in the shell, including one alongside the rear bulkhead linked to the rear coilovers (another custom installation) and a cross-member, this intended to mount to the harness I-bolts.

It's an impressive degree of chassis finessing, and only right and proper when you consider that this Imp will likely spend as much time on the track as it will the road. Its track-focussed nature is reflected in the spec of the engine, a Rodwell Motorsport built screamer.


"This was built for us by Rodwell and is masterclass in classic, old school tuning. It has a GE3 race spec cam, 25mm exhaust ports, multi-angled valve seats with enlarged throats, double valve springs, titanium collars and loads more. The block is actually from a Sunbeam and has a host of strengthening modifications, a high capacity sump, and houses billet rods and crank, 74mm cast pistons and a lightweight flywheel and clutch."

The best bit, aside from the Jenvey throttle bodies, combined inlet and exhaust manifold, and fully programmable ECU, is probably that this engine should be capable of revving all the way to 8,200rpm, which is something that has to be worth hearing.



Alfa Romeo Giulietta chassis legs
It won't be at all surprising that the Alfa Romeo Sprint we saw being worked on last time is still in the Retropower bodywork hall, but that's not to say that progress hasn't been made. As we mentioned last time out, this is among the most challenging restorations these guys have yet undertaken and as such represents something of an uphill battle for those charged with its rebirth, namely metalwork gurus Stu and Scott.

"Scott's TIG welding has improved to the point where he's easily among the best on the Retropower staff, and as such we thought it only fair to entrust him with the re-fabrication of the Alfa's chassis legs," explains Callum. "We actually only intended to remake and replace the passenger side leg but wound up chopping both out - we reasoned that there was little point leaving anything to chance."

These images really aren't for the fainthearted, and it turns out there's little more galling (in automotive terms) than a car sans its rear-three quarters and chassis legs. The process for remaking the latter - and it really is remaking in the truest sense of the term, as there's little to nothing available 'off the peg' for the Giulietta - sees a mix of high end tech, sophisticated machinery and good old fashioned nous.


"We began by tracing the profile of the leg using MDF, pausing to take measurements from the 'good' side of the car as we went along, the driver's side, which in turn allowed us to take dimensions every 20mm along the length of the 'leg.' This done, we were able to use CAD to draw up a replacement of the correct profile, after which we were able to fire up the trusty Retropower plasma cutter!"

Said plasma cutter was used to CNC a series of trial parts in sheet steel, by far the most accurate means of guaranteeing the correct dissents of the leg, and one rendered all the more important when you consider that the Giulietta's chassis is made up of both an inner and outer section.

Retropower then made a custom jig from box section steel, a means of ensuring everything remains straight and true while the various sections of leg are TIG welded into position - ample opportunity for Scott to showcase his skills.



Datsun 240Z - A New Beginning
The Datsun 240Z is one of those cars that it's quite hard to discuss without veering into automotive cliche, and your typical online article on the car will mention phrases like 'Japanese E-Type,' 'surprisingly effective rally car', 'prone to rot' and 'staggeringly valuable nowadays.' With all of those hackneyed tropes well and truly dusted off, we can get down to describing the 'Z' we have here.

It's a UK car, one that's lead quite a storied life to date, having been stripped to a bare a shell at some point in the 1980s and promptly forgotten about. It lay in a deconstructed state for the over a quarter of a century, at some point being covered in an individual's attempt at artistic expression and slowly, steadily degrading.

The good news is that, thanks to the rising value of Z-cars of all types, the Datsun was deemed a worthy project by a serial 240 buyer, and now, a Retropower customer. The car will eventually be returned to standard, though only once they've comprehensively sorted the bodywork. This process has already commenced, the Datsun having been baked, blasted and generally taken back to bare metal.



Mercedes W116 S-Class - Completion
As one project arrives, another leaves, in this case the W116 S-Class. A traditional restoration in the truest sense of the term, the S-Class has be one of the most challenging builds in Retropower's history, largely thanks to it being an immensely complex car when first built.

The Mercedes gurus amongst you will already be aware that the W116 was actually the first Stuttgart creation to be badged and sold as an S-Class, making it a significant model in the firm's long and storied history. This providence didn't prevent the 350SE from looking decidedly down at heel when it arrived at Retropower some years ago, a life spent dealing with British weather and British winter having taken its toll on its bodywork, trims and running gear.


"This very car has actually been in the owner's family from new, passing between various family members over the years and generally playing a small but significant role in his life," explains Callum. "He therefore requested that we fully restore it to original factory specification."

What followed was a truly in-depth restoration, one initially focussed on the big Merc's vast swathes of metalwork, before moving onto the application of the distinctive coat of Pine Green it now sports. The task was made rather simpler through Mercedes being impressively dedicated to their old models, with pretty much everything, be it a trim or a component, available new through the dealer network. For a price, naturally.


Where Mercedes parts supply is less comprehensive is when it comes to interiors, specifically interior fabrics, a problem further compounded by this being a mid-range, non-leather model. What followed was a frantic scramble around Germany the like of which hadn't been seen since Operation Paperclip, with plenty of frenetic phone calls and more than a few duff leads.

"We did eventually trace a trimmer with access to a small amount of suitable fabric, though nowhere near enough for the whole interior. We therefore had to ask said specialist for the contract details of anyone who'd bought the material in the recent past, then contact them in turn." chuckles Callum.


Fully trimming the S-Class proved to be a stern test for Retropower and their in-house interior specialist, Trimworks, but it's hard to deny that it was worth the graft. Not only is the inside of the W116 fantastically comfy, but it really does look as pristine as it did way back in 1973, as does the exterior now that it has been fully detailed.

The W116 will shortly be leaving Retropower for the final time, destined to take pride of place in a specially built viewing area inside the owner's house - it's just as well the guys from Retropower have invested so much time and attention on every single detail.



Manta 400 Replica Paintwork
Opels - Mantas and Asconas in particular - are writ large in the history of Retropower, so it's only fitting that we take a closer look at the later example of Russelheim's finest to pass through.

The most iconic Manta of all was of course the 400, the car devised by GM Dealer Sport to go Group B rallying in the 80s. While the rear-wheel drive, carb-fed coupes found themselves outgunned and out-tractioned by the likes of the Quattro on gravel, they were able to give a very good account of themselves on tarmac, particular in the British Rally Championship, and a generation of wannabe Jimmy McRaes and Russell Brookes was spawned as a result.

The owner of this car is a fully paid up Manta fan, and the 400 in particular. However, while genuine 400s were powered by 2.4 I4 CIH engines, this one will eventually receive a V8, a far cry from the demands placed upon Opel by the need to conform to homologation rules whilst seeking special stage victory.


Other aspects are more traditional, at least from a retro Opel perspective. It will ultimately sport the box-arches, front bumper and rear wing so redolent of competition Mantas of the time, while the paint, actually a new Volvo shade of silver, has been selected both for its looks and its visual link to the hue used on the original homologation 400, number 1 of 200.

"Much as it's nice to attempt new projects when they crop up, we're equally aware that Retropower has acquired a solid reputation within the Opel scene, and as such it's equally rewarding to build another Manta."

That's all for now, but we'll be sure to check back in with the team in the New Year. But don't panic, you can check out both their first update and our own visit to Retropower's HQ to tide you over until then!

P.H. O'meter

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Comments (15) Join the discussion on the forum

  • Jerseyhpc 01 Dec 2018

    You got to love these virtual visits to Retropower. Seeing the skill and dedication applied is a joy and knowing that there are enough people holding doctorates in Man Maths is very heartening.
    I still adore the Imp

  • Fluid 01 Dec 2018

    Their YouTube series on the Gordon Murray Mk1 escort, is outstanding.

  • GranCab 01 Dec 2018

    A.F.A.I.R. The Hillman Imp never had the twin headlamp front end ... that was only seen on the Singer Chamois and Sunbeam Stiletto versions.

  • CanAm 01 Dec 2018

    It never had lots of things this car has got. That's the point of it.

  • jet_noise 01 Dec 2018

    Imp must hear smile

    Cavil: That paint colour.

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