We visit GTC Engineering and meet the family team behind its success
FIRST, THE NAME. As we know, there has never been an Aston Martin GTC. ‘I like Italian exotics,’ says GTC Engineering’s co-founder and now owner, John Winsor. And Italian exotics are what dominated Grand Touring Car Engineering’s workshops back in 1975, when John started the company with Richard Colton, collector of Ferraris and other expensively sporting machinery.
Cast your eyes today over the automotive inmates of GTC’S workshop near Silverstone and yes, you will spot the odd Ferrari or Lamborghini. But Aston Martins dominate, as they have done for years. Still, the GTC name is well known, so why change it?
GTC today is a family firm, with John at the helm, son James his right-hand man, wife Anne and daughter Kim keeping the admin running smoothly. Also fettling the covetable cars that populate the GTC emporium in a former farmyard off the Dadford Road are Dave (builder of engines and sub-assemblies, formerly of Cosworth), Paul (mechanical and electrical work, trim) and Ollie (trim and assembly work).
It was a different picture 25 years ago, when GTC had over 20 employees and 30 restorations on the go at any one time. Richard Colton had moved on to other things by then, and John was running it all. It was becoming a bit too much, and then in the early 1990s the classic-car boom turned to bust. In some ways that was a relief for John, who seized the moment to relocate to a smaller workshop in Northampton, where GTC stayed from 1992 until 2004 before moving to the present buildings.
Today, as well as servicing, repair and restoration of (mainly) Aston Martins of the Feltham and Newport Pagnell eras, GTC does a nice line in improvements. The two for which it is best known are its own take on an electric power steering system and an improved steering box for the Feltham Astons (DB2 and derivatives), a fame which will shortly have a third strand in the form of the Jenvey Heritage Throtte Body, which GTC helped develop (as reported in the previous issue of Vantage).
BEFORE WE EXAMINE THESE, and GTC’S other activities, we shall uncover more of the story behind this company’s curriculum vitae. Go back to the beginning, and John tells of the two key things that happened to his young self to set him on the GTC road.
One was being born in Newport Pagnell (in 1949) and growing up there, which led to a school tour of the Aston factory and the chance to sit in one of the James Bond DB5S. The other was being driven at 100mph by his cousin, Tony Rudd, in a Ford modified by Raymond Mays, after John had visited the BRM factory.
Rudd was BRM’S chief engineer, a position he later held at Lotus’s road car operation. ‘It was very special to have Tony as a cousin,’ John remembers fondly. ‘His mother was my great aunt Mildred, whose sister Jessica was the nanny to Prince Chula’s daughter, Nerissa. That’s how Tony got into motor racing.’ (Prince Chula of Siam ran a racing team in the UK, with which his racing-driver cousin Prince Bira had great success.)
John himself started racing in his late teens, moving on to autocross and rallycross and always preparing his own
cars including, by 1976, a championship-winning MiniCooper S. After a year at university – ‘It was not for me’ – and work in the engineering industry, where he learnt design and machining skills that have proved very useful over the years, he started working on cars full time in the late 1960s. It was while working for Michael Grady, an Aston expert who ran a Fiat and Ford dealership with his brother, that John had his first hands-on Aston experience – fixing Michael’s DB2/4. Grady Brothers had customers with ‘interesting’ cars, too, so John was soon familiarising himself with a DB5, a Ferrari 250 GTE, a Jaguar E-type, a Porsche 911, an Allard J2 and more.
Afew years later, a customer came into the garage where John was working to seek help with a Bentley Speed Six that wouldn’t start, and a Ferrari 275 GTB whose engine was seriously out of tune. That customer was Richard Colton, whose recalcitrant cars John soon had running well. So an idea formed between them, an idea that became GTC Engineering which the pair duly set up in Higham Ferrers, Northamptonshire.
The enterprise went well, growing into bigger premises in Rushden as ever more Ferraris clamoured for attention, including Richard’s own 250 LM, 250 GT SWB and 275 GTB4. Then Richard bought an Aston Martin DB4 GT while John acquired a DB2/4, swiftly followed by the first Series III DB4. Richard left the enterprise around this time, too soon to see the DB4 become the subject of GTC’S first full body-off restoration, carried out in the mid-1980s with body panel specialist Shapecraft.
Business was really humming by now, with Aston Martin itself commissioning restorations from GTC. Some were of important cars such as DP199 (the original DB4 GT prototype), DP114/2 (a proposal, with de Dion rear suspension, to replace the DB MKIII, and canned in favour of the eventual DB4), DB4 101/R (the first production DB4), and the Bertone Jet (a special-bodied DB4 from 1960). GTC Engineering wasn’t credited with these restorations at the time, but it made sense to the factory to subcontract the restorations to the company best suited to the task.
‘I am very proud of these works,’ says John today, ‘but I have never really taken credit for them out of loyalty to the factory.’ The Bertone Jet was a particular challenge, having been left by the side of the road in California after an underbonnet fire. ‘I first saw it in the service department at Aston Martin. It was in a dreadful state after that fire, and once we got it in our workshop we found rust by the bucketful. This was always going to be a difficult job, with
‘The Bertone Jet was a particular challenge, having been left by the side of the road in California after an underbonnet fire’
so much of the car rusted and burned, but I spent hours with Kingsley Riding-felce of Works Service discussing the project to get it right.’
During the boom years, GTC became ever more steeped in Aston restorations, including the DB4 Convertible used in Theitalianjob (and featured in Vantage issue 14), but Ferraris still figured along with a smattering of Maseratis, Jaguars, Coopers and Listers. John also hatched a plan with Clive Smart of Shapecraft to create what turned out to be three DB4 GT Zagato replicas. The factory was working on its own Sanction II Zagatos around the same time, but the Gtc/shapecraft interpretation beat them to launch by a fortnight.
And then came the downturn, GTC’S downsizing move to Northampton and, says John, ‘a more personal involvement’. Son James joined the business in 2000 and, via the move near to Silverstone, that’s where GTC is at today. It has weathered the turbulence of the market over the years and is fighting fit.
JOHN TAKES ME on a guided tour. My eye immediately falls on a red DB6 Mk2 in Brilliant Fast Red, its wheelarches subtly flared, awaiting final fitting-up. There’s a Mercedes-Benz 190SL in front of it; GTC is not all British and Italian.
I then spot a steering column with an electric motor growing out of its side, sitting among neat coils of wire and an electronic box of tricks. This is GTC’S EPAC2 electric power steering conversion, the latest version of a system of which GTC has sold over 500 examples for Astons and a few for other cars. ‘We first looked at electric power steering around 15 years ago,’ John recalls. ‘I was sitting in a Fiat Punto with a City button, and I thought, “How does that work?” The silver DB5 here [the Jenvey HTB test bed] was the first car to have our system.’
We move on to the machine shop, where small runs of prototype parts are made. ‘We’ll make three or four to get them right,’ John says, ‘then have them made outside.’ Those parts include the components needed for GTC’S remake of the ‘Feltham’ steering box, most original examples of which are fairly worn-out by now. John reckons the steering was always tiresomely heavy anyway, and GTC’S steering box can reduce effort by up to 30 per cent. With many of the original components now beyond repair, GTC makes complete new boxes as well as the individual parts.
Two key pieces of equipment in the machine shop are a Bridgeport milling machine and a Shadowgraph, which projects the outline of a component onto a screen. That outline can then be transferred to GTC’S adjacent computer to become a CAD file, and checked for accuracy. And there’s more meeting of old designs and new technology in the engine room, where lives a Faro 3D measuring arm.
Accurate to two-thousandths of an inch, this sweeps around an object at up to a 6ft radius like a laser-scanning paintbrush. The data it generates can be used for comparing camshaft profiles at one extreme to complete reverse-engineering of components at the other, helped by GTC’S 3D printer. Just for fun, resident electronics whizz James scanned a complete engine and 3D-printed a 3inlong model of it.
As for the engine-building, that’s mostly John’s domain with help from ex-cosworth David. ‘That’s a torque plate,’ says John when I puzzle over a hefty lump of aluminium sitting on top of a Marek straight-six engine block, containing six bores to match the cylinders below. ‘The bores go slightly oval when the head is torqued down,’ he explains, ‘so we bolt this to the block at the right torque before we hone the bores of a rebuilt engine.’ And when the engine is finally built up, it will contain one of GTC’S own composite head gaskets, with seals specially designed to accommodate any corroded waterways that might exist in an aged cylinder head.
Other tasty parts therein might include Cosworth pistons, Arrow connecting rods – and tappet buckets coated with DLC (diamond-like carbon). ‘It’s all to do with stopping the scuffing in little-used engines,’ John says, acknowledging that an old Aston’s life today can involve activity much more sporadic than when new. Crankshafts and camshafts are typically billet items from RS Williams: ‘If we use a standard crankshaft, we’ll crack-test it first.’
Other GTC specialities are retro-fitting air-conditioning and updating transmissions. It has developed conversions using a ZF automatic gearbox or a Tremec T5 five-speed manual, including a ‘world class’ version of the latter with carbonfibre synchromesh rings and better bearings. One conversion for an Aston Martin V8 involved a General Motors 4L ATE automatic gearbox with a ‘trick’ valve body and six ratios instead of the usual four. There are creative minds and a can-do spirit at work here.
ON THE DAY of our visit, a DB6 had just been driven to GTC from Guernsey for a pre-mot check. Another DB6, prepared for classic rallying by GTC ten years ago, was back from a trip around the world in 80 days that included the Gobi desert. ‘It’s done 110,000 rally miles,’ reports James in amazement. ‘I think we’ve de-sanded it now.’
Meanwhile, GTC also sends parts to Europe and the US, plus Hong Kong, where EPAC2 is much liked. Brexit produced a spurt of interest here: ‘We had an order from Hong Kong the day after it was announced,’ says John, ‘as soon as the pound dropped. Now we’ll wait and see what the future brings.’
Whatever that turns out to be, GTC will continue to do what its does best and loves most. As soon as you step through the door, you sense this is not an operation driven by profit and ruthless efficiency: there is not a molecule of corporatism here. It’s a business, of course, but one based on enthusiasm, for trying new ideas and for doing the job right. Exactly, in short, what a specialist should be.
Clockwise from above GTC’S roots were in Italian cars. It’s mostly Astons these days, but you still see the odd Ferrari (and other marques) in the workshops; team is led today by John Winsor (far left in line-up); trim specialist Ollie, and John’s son James at the computer as Shadowgraph shows profile of a steering-box worm
Clockwise from bottom left Mercedes SL one of a handful of non-astons at GTC on the day of our visit; components for a Feltham steering box; James Winsor drives the Faro 3D measuring arm; dad John in the engine shop, a Marek block and torque plate behind him, and mechanic Paul at work on a refurbed axle
Right Father and son, John and James Winsor, and (below) the present GTC workshops near Silverstone