If the French language had a word for derring-do, it would unquestionably be applied to Georges Regembeau. This free spirited and largely self taught engineer born in 1920 in San Francisco, but who spent all but the first few months of his life in the Rhone valley where he died 85 years later, might have been France’s JC Bamford.

But if Bamford famously built a business around a tractor with a shovel at one end and a scoop at the other, Regembeau was more like a grass hopper, barely finishing one project before leaping into another. By the age of 14, he had built himself a tractor and by 17 his innovative repair of a road tarring machine which broke down outside his home earned him a handsome sum from a Mannheim company which patented his modification. Barely 18, Regembeau went out and bought himself a car, but not some banger, rather a Citroen Traction 15/6, then the most advanced mass production car in the world. Overnight he became the talk of the district. After the war during which he was imprisoned, but escaped using duplicate keys he had fabricated himself, he rallied his Citroen and even entered in the Le Mans 24 hour race. 

Particularly impressed with the Traction’s front wheel drive handling, he realised the chassis could cope with rather more than the 77bhp of the ‘Six’ and set about supercharging it and devising his own mechanical fuel injection. For good measure he also built a six speed gearbox with a hydraulic clutch, the highest ratio endowing the Six with a remarkable 210kph top speed, verified by an officially timed run at Montlhéry. Regembeau supercharged another four 15/6s for customers, but today, to his son Patrick’s regret, no one seems to know what became of the fastest Tractions ever built. 'I can remember one of them in the field behind our yard. We used to play in it as kids, but one day it had just disappeared.' Georges Regembeau would experience further unexplained losses as his fame grew.

He continued his remarkable engineering career through the 1950s, buying an army surplus truck, fitting it out as a workshop and becoming an itinerant repairman, specialising in plant machinery and the ex-US army trucks which, ten years after the war were mostly in dire need of maintenance. It was during this rampantly creative period that Regembeau built a couple of bulldozers, fabricating everything himself except the tracks, and even dragline cranes. But cars were his real passion and in 1964 he settled at a tumble down farm beside the route nationale 6 at Crèches sur Saone south of Macon.

Again, doing most of the work himself he transformed these premises into a wayside garage and workshop. Exactly half way between Paris and Marseille, Regembeau’s centre routier became well known and rapidly he found himself servicing on only trucks and cars, but also the motorgraders and other plant working on the new autoroute which ran almost in front of his garage.

He was fascinated (as were all car engineers and enthusiasts) by the Citroen DS and enterprisingly acquired a small fleet which he rented to passing travellers or holiday makers so that they could continue their journey while their car was being repaired. Regembeau’s penchant for la marque aux chevrons saw him developing various modifications to improve the reliability of the DS. Besides work to make the hydraulic seals more oil tight, he devised a five speed gearbox, greatly improving the car’s refinement and economy on the new motorways in particular.

Then he moved to tuning and with judicious changes to its cylinder head and induction system, the later DS 21 was capable of a staggering 220kph. It was useful publicity for Citroen and the company took notice and ordered a pair of Regembeau’s five speed gearboxes for its two entries in the 1970 London – Mexico rally. A few years later Citroen itself started to manufacture a five speed remarkably similar to Regembeau’s design, but never acknowledged him. Indeed Patrick Regembeau says there is some question whether Citroen ever in fact paid for the two gearboxes and undoubtedly the firm came to resent his work because it demonstrated shortcomings in its own engineering. Worse would follow.

In 1968, Citroen became the major shareholder in Maserati: Citroen was after Maserati’s V6 to power its forthcoming SM and at last endow a big Citroen with the six cylinder unit always sadly lacking in the DS. But shoehorning the Modena V6 conceived for rear wheel drive into a front wheel drive chassis posed technical problems. Effectively, the engine had to be redesigned, a task which fell to Guilio Alfieri.

While his basic conception was sound, the engine was built hastily and with woefully inadequate development, rather in the same way as its contemporary, the 3 litre Triumph Stag V8. It would not be long before Georges Regembeau found himself peering beneath the SM’s elegant bonnet staring at a failed engine, but before that came the oil shock of 1974 when suddenly petrol became vastly more expensive. Regembeau began proposing a diesel conversion to SM clients whose engines were giving them problems. He had already built a 2 litre four cylinder diesel which he had offered for the DS and the promise of better economy combined with a lower pump price made this an increasingly attractive option.

Regembeau’s oil burner, which characteristically, he created absolutely from scratch, produced 85bhp. But by the early 1970s, experiments with Bosch Mechanical injection and successive increases in capacity to 2.6 litres eventually produced a reliable 180bhp, enough to push the 1450kg SM to almost 200kph.

Citroen in the meantime went bankrupt and the French government prevailed upon Peugeot to take over la marque aux chevrons. Peugeot’s own plans for a prestige car, the 604, were well advanced and as the SM represented competition of a sort, it was dropped, as was the project to install the Alfieri V6 in the forthcoming CX. This made an unfortunate orphan of the strikingly styled SM and Georges Regembeau now turned his attention to its troublesome V6.

The Achilles’heel of the Alferi design was its fragility. It was built like a racing engine with very limited tolerances: precise cam timing was crucial as the valves only just cleared the pistons, yet the ill lubricated timing chains had no tensioners and with wear, readily lost their setting. The sodium filed exhaust valves were especially prone to corrosion which could cause them to snap and fall into the engine….flexing of the block loosened the cylinder liners… the oil pump drive was under specified and sheared….

There was a veritable catalogue of disasters waiting to befall unfortunate SM owners and they soon discovered to their cost that maintaining an SM entailing visiting both Citroen and Maserati specialists. Regembeau understood the V6’s flaws and realised that nothing short of ground up re-engineering would make the engine run reliably. Starting from the bottom end, he worked steadily, revising crankshaft, main bearings, piston liners and installing solid valves. He redesigned primary timing chain with better lubrication and added automatic tensioners to this and to the secondary belt which had the arduous responsibility of driving the alternator, a/c compressor and the hydraulic steering and suspension systems.

He redesigned the cylinder heads using better quality steel, concluding that Modena had machined the originals without sufficient hardening of the metal. Regembeau’s revisions to timing and induction and exhaust manifolds lowered peak torque from 4000rpm to a more relaxing 3000rpm, and if the subsequent increase in torque was modest, power output went up to an impressive 240bhp with triple Weber 48 carburettors. Yet, claims Patrick Regembeau, this engine ran freely to 6500rpm and allied to Regembeau’s own six speed gearbox with its 56kph/1000rpm top ratio, the Citroen SM RG was potentially a 150mph car. His father’s prototype, which Patrick has recently rebuilt with hardened valve seats, reputedly gave 300bhp.

Unlike Bamford who steadily built up JCB’s manufacturing capacity, the stubbornly independent Regembeau was really more of an innovator than a businessman and as such remained a one man band. He was thus vulnerable not just to being sold short by big manufacturers, but open to unscrupulous operators of all hues who stole from him or produced fake RG engines which they passed off as genuine.

Patrick recalls that not only did equipment ‘disappear,’ but one terrible night in 1982 the entire workshop burnt down. Mysteriously the walls fell in too, causing maximum damage. Although officially described as a ‘fire’ to the Regembeaus though, this was obviously malicious, the work of envious local criminals, “la mafia locale,” Regembeau’s wife  Ginette calls them, and the culmination of years of unpleasantness. Loss was almost total. Only the handful of cars outside was undamaged.

Georges Regembeau was 62 and this catastrophe hit him hard. He went into a depression and the business all but ceased, kept alive by Ginette. But Georges Regembeau’s renown and the gratitude of clients who had become friends gradually helped so that in 1995, the Citroen Revue was able to publish an article titled ‘Papy fait de la résistance’ after the French ww2 film of 1983. This was one of a series of pieces which had been appearing in the motoring magazines and was written to celebrate his 75th birthday. Son Patrick gradually took over the business from a very reluctant father and today like his father used to, works alone, although his mother is an accomplished mechanic who has certainly served her time in the workshop.

 Today’s Regembeau operation is largely SM restoration. Explains Patrick: 'I undertake all the mechanical work and anything to do with the suspension and steering. The only part I subcontract is upholstery and bodywork.' The main demand is renovation of standard SMs.

'These cars have to be used,' goes on Patrick, 'but often they’ve been laid up for a long time which means a complete rebuild, not just of the engine, but the suspension and the interior. I can still do "Regembeau" conversions and even build the V6 engine from scratch, but the moulds to build the diesel are long gone which means I’m doing only restorations of the four cylinder engines.'

In the best Regembeau traditions, Patrick remakes everything he can, but the starting point is always to consider whether an item is restorable. “Anything made in stainless steel is time consuming: cleaning up an SM hubcap takes hours so it can cost €150. If you reckon €400 for the correct 195 tyre, sorting out the wheels alone is over €2000 – fixing an SM can cost as much as buying a new one used to!”