Often regarded as the last of the traditional British sports cars, the Triumph TR6 is also the last ‘proper’ Triumph. Here’s what you need to know
Words: Aaron McKay Images: James Howe
Triumph’s cost-effective method of modernising its traditional TR sports car range for the 1970s, the TR6 was essentially a tidy facelift of the TR5 carried out by German coachbuilder Karmann, adding a squared-off front and rear influenced by Michelotti’s styling on the company’s saloon models.
Launched in January 1969, it was not a radical leap forward for the TR series, but it was far from insignificant. Underneath it remained closely related to the TR5/250, with a separate chassis and a front-mounted straight-six engine driving the rear wheels through a four-speed gearbox. The TR4A had already introduced independent rear suspension, and rack and pinion steering had been in place since the TR4. For the first time, however, a front anti-roll bar was fitted.
The most obvious change on the TR6, and one that divided enthusiasts of earlier cars, was its revised nose and tail, giving it a more muscular look compared with the softer styling of previous TR models.
It did, however, neatly house wider 5.5-inch wheels, larger bumpers and bigger lights. This proved ideal for the important US market, where the majority of TR6s were sold. Many have since returned to the UK, meaning we now see both fuel-injected home market cars and American-spec twin-Stromberg versions in almost equal numbers.
Once common practice was converting the troublesome Lucas fuel injection system back to twin carburettors. Today it is largely a matter of preference, as the injection can be made reliable and carburetted cars can be tuned to close the power gap. From the factory, UK cars produced 150bhp via Lucas injection, while US models were restricted to 105bhp due to emissions-controlled carburettors.
The earlier cars have commission numbers beginning CP or CC, the former denoting petrol injection and the latter carburettors. In 1972 the revised CR/CF series was introduced, bringing a new camshaft profile and a reduced compression ratio, dropping from 8.5:1 to 7.75:1, which lowered UK models to 125bhp.
There was also a revised exhaust system to match, plus the fuel tank capacity was reduced from 11.2 gallons to 10.25 gallons. At the end of the year, the rear springs and wishbones were uprated.
In fact, the TR6 changed every year of its production between 1969 and 1976. Cars from the first year can be identified by body-colour windscreens and chrome engine covers. In 1970 a raft of changes arrived, including revised pressed steel disc wheels and an option of 72-spoke wire wheels, along with a new inlet manifold on US cars. From this point onwards, windscreen surrounds were finished in black and engine covers were painted. In 1971, some components from the Triumph Stag were incorporated into the gearbox and a steering lock was added.
For 1973 there was a new front airdam, wiper arms changed to matt black instead of chrome, and the air intake became a black plastic item. A stainless strip was added to the top and bottom of the grille, while Union Flag decals replaced TR6 badges on the rear wings for American markets. Inside, headrests became standard and both switchgear and instrumentation were revised.
For 1974, overdrive became standard equipment and a tonneau cover was included. In 1975 a raised front bumper was introduced, along with lower indicator and side light units, while US cars gained rubber bumper overriders. It should be remembered that this reflects how the cars left the factory, not necessarily how they are today.
Triumph TR6 values
TR6 values today are broadly split into clear tiers depending on condition and originality. Project and barn find cars typically start around £5000-£10,000, but even at this level corrosion and tired interiors can quickly double restoration costs. Usable drivers generally sit in the £12,000-£18,000 bracket, offering solid structure, decent trim and a car you can enjoy while improving. Well-sorted examples with good history usually command £18,000-£24,000, with the very best, fully restored cars edging beyond £25,000, especially if they have overdrive, factory hardtops or strong provenance. Imported left-hand-drive cars, mostly from the US, tend to be around 10-20 per cent cheaper than equivalent UK right-hand-drive examples. Indeed, rust-free US imports can represent good value if the underside is solid. The best cars are original, well-documented UK examples with minimal corrosion and sympathetic restoration, as condition matters most.
Insurance Costs
1971 Triumph TR6, £15,000 value
Example quote: £109.97 or £127.97 with Agreed Value.
Quotation supplied by Lancaster Insurance. Tel: 01480 400761
Quote based on a 45-year-old marketing manager, access to another car, no claims or convictions, club member, 3000 miles per year, no modifications, living in SP2 0HL. Disclaimer: Subject to underwriting criteria. An additional charge may be payable. Authorised and regulated by the Financial Conduct Authority.
Bodywork
Beyond the usual checks for corrosion that can affect a 50-year-old car, the TR6 has several specific areas that demand close attention when buying. The worst chassis rust tends to appear on the sills and at the rear.
Inspect the full length of the sills, while also examining the floor panels and the rear axle mounting points. We asked Gary at Triumph TR specialists TRGB what to look for, and he explained that the T-shirt-shaped pressing that sits over the axle needs careful inspection, along with the two trailing arm sections, which can rust from the inside out. How do you spot it? “Look for swelling around the bolts, that is how they start. If they let go, fixing it can involve taking the body off.”
It is always wise to check the outer panels for signs of poor repairs or simply how well the car sits. The TR6 was never built to the tightest tolerances, but if it looks wrong you should be cautious. Gary added: “do not expect panel gaps to be perfect” but “if the door gaps are opened up at the B-post, that is a sign that the chassis is starting to sag. It is actually the opposite to most other open-topped cars. The weight hangs at the back.”
Another weak spot is where the rear wings bolt to the deck, where Gary notes that “three layers of metal go together in a sandwich. Dirt and debris get kicked up from the road and trapped here, and will eventually rot them out.” This area can be difficult to repair due to the outer, inner, and deck joins, although once sorted an effective long-term fix is to protect it with a wheel-arch liner.
Other corrosion-prone areas include the B-post backs, the front wings around the headlights, the leading edge of the bonnet, and the rear lip of the boot lid. Many cars will have been resprayed in the past, so the extent of corrosion will largely depend on the quality and timing of previous paintwork.
Engine and transmission
The straight six is generally a reliable unit, provided it has been properly maintained. One area that must be kept on top of is crankshaft endfloat, which, if ignored, can lead to serious damage. Gary is very familiar with this issue and explains that to avoid a full rebuild it needs catching early, when it can still be corrected with the engine in situ. A useful check is to look for excessive play in the engine pulley when the clutch is operated.
Other points to note are that these engines are sensitive to ignition and camshaft timing, and injection models benefit from uprated fuel pumps, so it is always encouraging to see a car maintained by an attentive and knowledgeable owner in these areas.
The drivetrain can suffer wear and occasional damage from abuse. The weakest area is the rear axle, where differentials are prone to leaks. Gary has seen many examples arrive at TRGB with this type of wear and says the driveshafts are particularly troublesome.
Fortunately, parts are readily available so issues can be resolved, though with driveshafts it can be sensible to upgrade. TRGB’s CV conversion, at £840 a pair including the hub plus VAT, is a popular choice. Listen for clunking from the rear end as a sign of these problems, but note that differential mounts can also fail and produce similar symptoms.
The gearbox is based on the Triumph TR4 unit and, although it was refined during the TR6’s production life, it can still suffer from hard use. Gary explains that “the layshaft bearings wear, causing noise in first, second and third gears. You also need to watch the clutch release bearings, which simply do not last. If you get 60,000 miles you will be lucky, because if you are driving your TR6 enthusiastically they tend to last only 12,000-20,000 miles.”
Suspension, steering and brakes
The Triumph TR6 is independently sprung at all four corners on coil springs with lever-type dampers. The rear end in particular benefits from refurbishment with fresh components, especially the suspension bushes.
“We tend to recommend polybushes, just not on the differential, and we quite like GAZ adjustable shocks as an upgrade,” says Gary. “We’ve also had new springs made for us recently by a British manufacturer in a new material, chrome silicon.” Parts availability is improving all the time, and you can now set a TR6 up for everything from relaxed touring to full-on track use. Dampers are often converted to telescopic units for either approach.
Although new components are generally reasonably priced, a car needing extensive work can quickly become expensive, so it is worth bearing that in mind. The front suspension also needs regular attention, as the trunnions must be kept well lubricated.
Factory guidance was to service these every 1000 miles, but most owners and TRGB now take a revised view. “We fit hypoid grease and then lubricate them. The trunnions will always leak, so we tend to use grease as the main maintenance point, around every 6000 miles or depending on wear.”
Interior & Electrics
The TR6’s cabin is well appointed and fairly spacious, although it is usually the trim details that let down an otherwise tidy car. The wood veneer can suffer from lacquer flaking over time, which is easily sorted with a replacement dashboard panel at around £300, while wooden door cappings typically cost about £200.
The seats are another common weak point, often found torn and sagging after more than 50 years of use. Foam kits and new seat covers are available to restore the originals, although buying complete kits for both seats can come to close to £900. More budget friendly alternatives include used seats for around £300, or the popular Mazda MX-5 seat conversion, which improves support, looks reasonably period correct and is considerably cheaper overall, with the required mounting rails costing about £52 each.
Electrics are typical 1970s British fare, with most issues usually traced to poor earths or deteriorated wiring rather than major faults. It is worth checking the fusebox for corrosion and ensuring all connections are clean and secure. If you plan to drive at night or tour in your TR6, upgrading to LED bulbs inside and out is a worthwhile and inexpensive improvement, reducing strain on the electrical system while improving reliability and visibility.
Triumph TR6: our verdict
The wealth of expertise and variety of available parts means that anyone with a Triumph TR6 can not only restore their car from the ground up but also tailor it into whatever they like, whether that is a blend of different model years or something far more ambitious using the excellent range of aftermarket products on offer.
In fact, the Triumph TR6 is one of the most appealing in the TR series for modification because it responds so well to upgrades. The lower-tuned engines in particular have plenty of performance waiting to be released, and so too does the chassis. With suspension changes such as polybushes, or even Mazda gearbox conversions, you can end up with a sports car capable of worrying much more modern machinery.
