Buying Guide Triumph GT6


Buying Guide Expert guidance on sourcing the best Triumph GT6 for your money while this baby Jaguar E-type is still a bargain

Six steps to buying a Triumph GT6


Until recently the GT6 was underpriced for what it offers – the hatchback configuration and smooth, torquey 2.0-litre six-cylinder engine make it a capable grand tourer. Values have risen noticeably over the last few years, but this is still a classic that’s affordable to buy and run. DIY maintenance is straightforward, especially forward of the windscreen thanks to the flip-up front end. If you fancy buying a project the GT6 is easy to restore at home, but whether it’s financially viable is another matter. Parts availability is very good, although some used items are getting costly and the quality of some new bits is variable. Our guide pools the knowledge of Triumph Sports Six Club (tssc.org.uk) GT6 register secretary Andy Cook and valuations officer (and GT6 owner) Jane Rowley, along with David Aspinall of Anglian Triumph Services.


Which one to choose?

1 GT6 MkI was launched in October 1966, using the Vitesse’s 95bhp 1998cc straight-six engine and four-speed manual gearbox with optional overdrive. Front and rear ends used the Spitfire MkI/II lighting and bumper arrangements. Production totalled 15,818.

2 GT6 MkII arrived in October 1968 with a TR5 cylinder head to give 104bhp, and Rotoflex rear suspension in place of the MkI’s swing-axle layout. Styling changes included the higher bumper of the MkIII Spitfire along with louvres in the top of the bonnet and front wings. Rostyle wheel trims replaced the MkI’s disc wheels and louvres were incorporated into the C-pillar behind the rear side windows. Interior ventilation was greatly improved and a heated rear window was standard. GT6 MkII production ran to 12,066 examples.

3 GT6 MkIII debuted in October 1970, with Spitfire MkIV styling cues, a deseamed bonnet and sharper, cut-off rear styling. A revised MkIII arrived in February 1973 with swing-spring rear suspension and new instrumentation. The final GT6 was made in November 1973, after 13,042 MkIIIs had been produced.


Bodywork and structure

Three main sections make up the GT6’s structure – chassis, main body tub and front wings/bonnet assembly. The majority of the car’s strength is in its chassis, and its condition can make the difference between an easy restoration and a major body-off rebuild. If the panel fit is poor, the car might have been in an accident or poorly restored with incorrect alignment. Panel gaps are frequently large or uneven, but a properly restored car will have reasonably tight shutlines – a quarter of an inch at best.

Significant chassis corrosion is unlikely, but check for rot on the MkIII where the front over-riders bolt on. The outriggers can rust, but there’s only one on each side and these can be repaired for as little as £250 each.

DIY MAINTENANCE IS STRAIGHTFORWARD, ESPECIALLY FORWARD OF THE WINDSCREEN THANKS TO THE FLIP-UP FRONT END

Potentially much more of a problem is front-end impact damage. Says David Aspinall, ‘This seems to be most likely on the MkIII, so look behind the radiator and around the steering rack for bulging or distortion. Repairing impact damage is tricky because it will throw the panel gaps out. Your best bet is to find a decent used chassis because new ones are unavailable. Replacing a chassis is a big job because the whole car has to be dismantled.’ David reckons he’d charge around £3k to supply a decent used chassis and swap everything over on to it – although he adds that such an exercise is very rarely required in his experience.

The sills rot and they’re crucial to the car’s strength; replacement needs to be carried out with the bodyshell in situ and ideally with a brace across the door gap to prevent the bodyshell distorting. Specialists charge around £1000 per side to repair the sills.

PARTS AVAILABILITY IS VERY GOOD, ALTHOUGH SOME USED ITEMS ARE GETTING COSTLY

The brake and clutch master cylinders are on the offside of the bulkhead; these leak fluid which strips the paint leading to rot and a £300 bill if you dismantle and reassemble everything yourself. The battery tray is positioned on the nearside and its drain hole blocks, eventually causing rot; budget £200 to fix this.

On the MkIII the top of the roof can corrode because of condensation forming between the metal and the headlining; it rusts from the inside out and repairs cost £500. The A-pillars suffer from the same problem, which adds another £250 to the bill. Earlier cars have a separate windscreen frame, shared with the Spitfire and TR4/5/6, that can rust in the lower corners. Decent used replacements cost from £100.

Water collects in the door seams between the casing and the skin. The first sign of problems will be when the metal has rotted through and the paint starts blistering. Fixing it costs £1000-£1500 and by this point replacement sills will probably be needed too. The seams around the car can harbour rust; front and rear wings carry them along the tops, and the panel between the rear lights can also give problems. Budget £350-£1200 per corner to rectify, depending on whether replacement panels and extensive welding is required.


Engine

All GT6s got a 1998cc straight-six which lasts for 100,000 miles if serviced properly, although they tend to leak oil from the rear of the cylinder head gasket. The crankshaft thrust washers can wear and drop out – reducing the engine to scrap – so check for play by pushing and pulling on the crankshaft pulley or depressing and releasing the clutch; there should be no more than 0.015m movement. Decent used engines cost at least £300, a complete rebuild around £2000.

The original canister oil filter should be replaced with a spin-on conversion; at just £60 it’s a worthwhile investment. The standard filter has no anti-drain valve, starving the bearings of oil on start up.


Transmission

An all-synchromesh gearbox is fitted to all GT6s, with overdrive an option – when it was specified the differential ratio was lowered from 3.27:1 to 3.89:1 to improve acceleration through the gears. If overdrive is fitted but not working, the fault is probably a loose connection or faulty relay. Sloppy gearchanges are caused by the plastic bushing at the base of the gearlever wearing out – an easy £18 fix.

Gearbox internals can suffer, especially with uprated engines. Mainshaft tips wear badly and layshafts fail, necessitating a complete rebuild. Exchange overdrive gearboxes cost £560; non-overdrive transmissions are £385. Dolomite 1850 internals can be fitted to beef things up, but are now in short supply.

If the car has Rotoflex rear suspension make sure the rubber-metal couplings are intact. Even the best ones (made by Metalastik, £200 apiece and now rarely available) last only 30,000 miles; cheaper alternatives can wear much faster. An upgrade to CV-jointed driveshafts is a more robust solution, at around £600.

The rear wheel bearings run directly on the shaft of non-Rotoflex cars, so will wreck the half-shaft if they wear out and break up, leading to a £200 repair bill. Even replacing the bearings is tricky – it needs a very heavy duty hub puller or even an industrial press.


Steering, suspension & brakes

Front trunnions can give trouble if they haven’t had EP90 oil pumped into them annually or every 3000 miles. Failure to do so leads to corrosion in the uprights which then snap. Check for heavy steering. Replacement uprights cost £137 each.

The steering rack is under the front of the engine so its mountings perish from being soaked in leaked oil. This leads to vague steering but new poly bushes are just £8.50 each. Bushes, dampers and brake calipers are both readily available and reasonably priced.

The original 4 ½ in steel wheels are often swapped for wires or alloys. Check for evidence of the tyres making contact with the bodywork because of incorrect offset – 175mm-wide tyres are the broadest that will fit.


Trim

The interior trim is durable, but if replacement is needed Newton Commercial produces excellent kits, including a moulded carpet set (£482). A new headlining costs £111, door trims are £126 per pair. Seat refurbishment can be costly; foam kits are £364-£430, cover kits are £314-£942 depending on variant.

The electrical system is very simple; the most likely cause of problems is bullet connectors breaking and corroding. Mkl and Mkll GT6s have some stainless trim fitted, but the MkIII dispensed with most exterior embellishments. Although new parts are pretty much universally unobtainable, it’s possible to source anything secondhand, most of it at low prices.


Electrics behind the dash can suffer if the windscreen leaks. Quality replacement carpets and trim is available.

This is a MkII, the rarest and most sought-after GT6, featuring louvres on the bonnet, front wings and C-pillar that greatly improved interior ventilation.

The 1996cc straight-six makes long-distance cruising effortless. It’s a generally reliable unit, but beware of worn crankshaft thrust washers that can wreck.

The Triumph GT6 was always intended to be a practical sports car for those on a budget, and as our experts and owners reveal, that remains true if you buy with wisdom.


What to pay

1 The MkII is the rarest and sought after, along with the MkI for its purer styling. MkIII is most plentiful/affordable.

2 Projects £3k-£4k depending on condition and variant; roadworthy cars start at £6k for a MkIII or £7500+ for MkI/II.

3 Top-notch cars are £12k for a MkIII. £15k for earlier models. Concours cars can an £8k-£10k premium, with the best early cars selling for as much as £25k.

4 Triumph didn’t offer a convertible, but lots have been made using a Spitfire body tub. Prices are on a par with MkIII values.


Owning a Triumph GT6

Chris Edmonds, Leicestershire

‘I bought the GT6 MkII shown on these pages in 1971, when it was just 18 months old. For the first four years it was my everyday car, then in 1975 the engine started making expensive-sounding noises so the car was put away in my garage. Then in the mid-Nineties I braced myself for an expensive engine rebuild. I started by removing the rocker cover and there was the problem – a broken valve spring, replaced for just a few pence.

‘Despite the low mileage I reground the valves, fitted new pistons and cleaned out the carburettors and the car has run perfectly since; it now has 80,000 miles on the clock. It’s great for road trips; I’ve taken it to Europe on numerous occasions, as well as all over the UK. I do all of the maintenance myself; the key is to insist on British parts where possible.

‘The GT6 is lovely to drive and frugal too; on a run it’s easy to get 40mpg. DIY maintenance is also straightforward and with parts generally cheap and readily available these cars cost very little to run. I do 3000 miles each year in mine and I average less than £300 per year for all maintenance because everything tends to last for so long.’

Jane Rowley, Gloucestershire

‘I bought my GT6 MkI 11 years ago; it keeps company with three Triumph Spitfires and a Herald. My GT6 was rebuilt by a fellow TSSC member who incorporated a series of modifications to make it more usable and since I bought the car I’ve made quite a few more changes to make it more comfortable or reliable; these include a high- torque starter motor, stronger brakes and uprated suspension. I use it for classic car runs, shows and also European touring; it’s crossed the Channel on several occasions. The GT6 is perfectly suited to such trips with its hatchback practicality and muscular six-cylinder engine, which is even nicer on twin SU carburettors instead of the original Strombergs.

‘Although these early GT6s are now unusual, there are still quite a few of the later models around, especially the MkIII. As a result it’s possible to buy quite a few things off the shelf to upgrade the GT6, while all sorts of bits from other Triumphs will also fit, which makes it easier and cheaper to make improvements – helped further by an army of club members happy to chip in with time and expertise when needed.’

Andy Cook, Hampshire

‘I’ve owned my GT6 MkIII since 1988 and have covered around 100,000 miles in it. Originally it was my only car and in reasonable condition, but rot necessitated an extensive body restoration and full respray in 1992 which cost £2500, then another in 2006 for £3500.

‘I do all mechanical repairs myself with virtually every mechanical component now rebuilt or replaced. The reconditioned engine fitted in 1993 cost £700 and has now clocked up 90,000 miles; in that time I got through three gearboxes, because they seem to last just 30k miles or so – the last one was £175 exchange in the late Nineties. I’ve swapped the original 3.89 differential for a Spitfire 1500 3.63 unit for greater durability and more relaxed cruising.

‘For many years it suffered from overheating and pinking in hot weather or traffic. The electric fan was the source of the problem and with this swapped for the standard mechanical one the car now always stays cool and it no longer pinks.

‘Removing restorations from the equation I spend on average about £600 per year for items such as wheelbearings, brakes, batteries, tyres and routine servicing.’


1973 TRIUMPH GT6 MkIII – £11,950

Sapphire Blue body & Shadow Blue trim. Overdrive. Rear seat option. Luminition electronic ignition. Spax adjustable dampers, Rotoflex rear suspension, four Firestones with deep tread. Although not a legal requirement, has an MOT until March 2020. Driven regularly and runs very well. A very presentable classic and usable vehicle with shiny paintwork. Two keys, owners handbook and Heritage Certificate included.

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