Grandfather’s Ax: The Many Evolutions of the Triumph TR4, Part 2: TR5, TR250, and TR6

With the debut of the TR4A in 1965, Triumph finally had a sports car with a modern fully independent suspension to match its crisp Italian styling, but the company soon decided the TR needed more power and a fresh suit of clothes. The results were two familiar-looking cars with completely new engines, followed less than two years later by a fresh-looking model whose specifications were pure déjà vu. In the second part of our history of the TR4, we look at the 1968-1976 Triumph TR5 PI, TR250, and TR6.

1968 Triumph TR250 badge

WASP: SIX INTO TR4

In our first installment, we chronicled the origins and development of the Triumph TR4, launched in the fall of 1961 to replace the previous TR3. An amalgam of several different styling studies by Turinese designer Giovanni Michelotti, the TR4 was essentially a new body on a warmed-over TR3A chassis, distinguished mechanically by a wider track, rack-and-pinion steering, and the standardization of the previously optional 2,138 cc (130 cu. in.) “wet-sleeve” OHV four.

The TR4’s new styling and greater civility were well-received, but many a critical spleen was vented at the harsh ride and unsettled rough-road handling. In response, Standard-Triumph developed a new chassis with fully independent suspension and mated it to a little-changed body to create the TR4A, introduced in March 1965.

1966 Triumph TR4A front 3q © 2009 AlfvanBeem PD AS
A Dutch Triumph TR4A convertible; next to it is a TR4A hardtop with the center roof section removed. Assuming both were originally European cars, both have independent rear suspension, which was optional on North American TR4As. The chrome rub strips across the front fenders and doors were new to the TR4A and one of the easiest ways to distinguish this model from the early TR4. (Photo: “Triumph TR4A dutch licence registration AL-47-75 pic1” © 2009 AlfvanBeem; dedicated to the public domain by the photographer under a Creative Commons CC0 1.0 Universal Public Domain Dedication, resized and modified 2012 by Aaron Severson)

The updated chassis gave the TR4A a much better ride if not necessarily better handling, at least on smooth roads, but underscored the fact that the TR could use more power. By the factory’s reckoning, the TR4A was 190 lb (86 kg) heavier than the TR3A, while engine output had increased by only 9 gross horsepower (7 kW) and 15 lb-ft (20 N-m) of torque. The TR4A was still one of the quicker cars available in its price range (around $3,000 in the U.S., £800 plus tax in the U.K.), but the giant-killing days of Triumph’s earlier TR2 and TR3 were a fading memory.

Deciding the best way to get the TR4 the additional power it needed was the subject of much internal discussion. It was certainly possible to coax more horsepower out of the existing engine — in racing tune, the 2,138 cc (130 cu. in.) four was good for a reliable 150+ horsepower (112 kW) — but doing so sacrificed much of its robust low-end torque and admirable fuel economy. Expanding the bore to bring displacement to a full 2,499 cc (152 cu. in.) was also a possibility, but meant redesigning the block and did nothing for refinement, an area in which the venerable three-bearing four had never particularly distinguished itself. There were also the forthcoming U.S. federal emissions standards to consider, problematic for a 20-year-old engine design. Standard-Triumph eventually decided that the wet-sleeve engine had had its day; the big four was now used only by the TR4 and a handful of Morgan Plus 4s, so sinking more money into its development was a questionable investment.

1969 Triumph 2.5 PI engine © 2012 Akela NDE CC BYSA 2.0 France
Triumph’s new fuel-injected 2.5 PI six-cylinder engine, seen here not in a Triumph TR5, but in a Mk 1 2.5 PI saloon. For saloon duty, the 2,498 cc (152 cu. in.) six received a milder cam, restricting output to 132 net horsepower (98 kW) and 153 lb-ft of torque (207 N-m), but improving low-end response: Torque peaked at only 2,000 rpm compared to 3,500 rpm for the more powerful TR5 PI engine. (Photo: “Triumph 2.5 PI Mk1 interior in Morges 2012” © 2012 Akela NDE; resized and used under a Creative Commons Attribution-ShareAlike 2.0 France license)

From the standpoint of production economy, the better choice was to adopt the newer straight six from the Triumph Vitesse/Speed Six and 2000 saloons. However, that was no solution to the TR4’s power deficit: as used in the big saloon, the 1,998 cc (122 cu. in.) six gave away 14 hp (10 kW) and 15 lb-ft (20 N-m) of torque to the elderly wet-sleeve four. Tinkering with the carburetion and cam profile improved power but not low-end torque, so Standard decided to redesign the six’s block to allow a hefty 19mm (0.75-inch) stroke increase. The result was a new 2,498 cc (152 cu. in.) engine that could be used both in a six-cylinder TR (codenamed Wasp) and future editions of the big saloon.

For the Wasp, Standard-Triumph raised the six’s compression ratio to 9.5:1, added a much hotter camshaft, and traded the saloon’s Zenith-Stromberg 150CD carburetors for Lucas Mk 2 mechanical fuel injection. Fuel injection was still racy stuff in the mid-sixties and Triumph would be the first British automaker to adopt it for a regular-production petrol engine; even most exotics still used Weber carburetors. Designed by the Lucas Injection Lab, the Mk 2 system was an adaptation of the Mk 1 setup used by some race cars, using a similar constant-pressure fuel pump and distributor-driven metering rotor, but unlike the racing system, fuel flow was controlled by six vacuum-operated butterflies rather than a mechanical throttle linkage. Because fuel metering depended on engine vacuum, its precision at off-idle speeds was less than ideal, but testing in 2000 saloons from the works rally team revealed that the injection system’s long intake runners and improved fuel distribution provided much better drivability with the wilder cam profile than carburetion. The result was a satisfying 142 net horsepower (106 kW) and 164 lb-ft (222 N-m) of torque from an engine very little larger and actually a bit lighter than the old four.

1968 Triumph TR250 bonnet
While the bonnet of the six-cylinder Triumph TR5 PI/TR250 looks the same as that of later TR4s, it is actually yet another variation with different bracing and latches than either of the two previous “long-bulge” versions. The protuberance was unnecessary with the six-cylinder engine, which sits slightly lower than had the four and had no carburetor clearance issues; we don’t know why Standard-Triumph didn’t simply eliminate the bulge. Wire wheels were optional on six-cylinder cars and much better looking than the standard wheel covers. (author photo)

The Wasp’s other changes were few. Larger front discs were added to cope with the additional power and an alternator replaced the previous generator, presumably to better accommodate the demands of the constant-pressure fuel pump. The previously optional brake servo and 165HR-15 tires were standardized, the rear springs were stiffened in an effort to reduce acceleration squat, and the rear axle ratio was reduced from 3.70 to 3.45 in hopes of preserving some semblance of fuel economy. In the cabin, the switchgear was revised to comply with U.S. safety regulations, but the only noticeable cosmetic changes were a slightly revised grille, “2500” badges on the rear fenders, and some rather tacky styled wheelcovers.

THE CARBURETED SIX

Standard-Triumph engineers had high hopes that the fuel-injected six would be an expeditious way to increase refinement, improve power, and meet U.S. emissions requirements all at the same time. Alas, the sticking point once again was cost. Since Triumph’s U.S. distributors had already balked at the price of independent rear suspension, it isn’t difficult to imagine their feelings about fuel injection, which would have added at least $400 to the TR’s list price. Moreover, the injected “2.5 PI” engine ran rich, particularly at low speeds, and Triumph soon discovered that getting the six to pass federal emissions standards would require the addition of an air injection pump, adding to the engine’s already substantial production cost.

1968 Triumph TR250 dash
The TR5 PI and Triumph TR250 had the same dashboard with the same basic layout as the TR4A dash, but with matte-finish wood veneer and new switchgear to comply with U.S. safety standards that took effect January 1, 1968. This dash was retained on the TR6. (author photo)

By contrast, simply lowering the compression ratio to 8.5:1, reverting to two somewhat modified Zenith-Stromberg 175CD carburetors, and making some minor engine changes (such as limiting maximum intake vacuum) would allow the 2,498 cc (152 cu. in.) six to pass muster without add-on hardware, reducing manufacturing costs significantly. The consequence was that the carbureted six was only fractionally more powerful than the big four, making 111 gross horsepower to the four’s 109 (83 kW vs. 81); net ratings were identical at 104 hp (78 kW) for both engines. However, the six still had considerably more torque — gross figures were 152 lb-ft (206 N-m) for the six, 132 lb-ft (179 N-m) for the four — and was much smoother and quieter than the old wet-sleeve four. The carbureted six also promised fewer service headaches than the fuel-injected engine — no doubt a reassuring point for the North American organization, which had been uneasy (rightly, as it turned out) about the warranty implications of the costly and unfamiliar Lucas injection system.

North American cars received a few other changes, many of them at the insistence of J. Bruce McWilliams, the former Rover executive who had become executive vice president of marketing for Leyland’s U.S. organization following the merger with Rover in late 1966. Most of the modifications were cosmetic: brighter colors and a contrasting paint stripe across the nose, tricks McWilliams had developed at Rover as an inexpensive way to pep up sales. North American cars retained the unfortunate mag-style wheelcovers, but more functional changes included the use of wider radial tires (185SR-15 Goodyears in place of the European car’s 165HR-15 Michelins) and the TR4’s shorter 3.70 axle ratio. There was also a new name. While the injected car would be badged TR5 PI (for “petrol injection”), the carbureted edition would be called TR250.

1968 Triumph TR250 side
The stripe across the bonnet and front fenders marks this as a TR250, which traded Lucas injection for two emissions-controlled Zenith-Stromberg 175CDSE carburetors, their mixture controls sealed to prevent tampering. Gross output was 111 hp (83 kW) and 152 lb-ft (206 N-m) of torque, 104 hp (78 kW) and 143 lb-ft (194 N-m) net. The live-axle/leaf-spring suspension standard on North American TR4As was no longer offered, so all TR250s had fully independent suspension. (author photo)

TRIUMPH TR5 PI AND TR250

The Triumph TR250 went into production in August 1967 with the TR5 PI following about two months later. Even with the cheaper carbureted engine, the TR250 was significantly more expensive than the TR4A, in part because the independent rear suspension was now standard: base price was $3,395 POE New York, over $300 more than a TR4A IRS. In the U.K., the TR5 PI’s basic price was at launch was a hefty £925 (£1,212 5s 5d with purchase tax), £125 more than a TR4A. By the spring of 1968, the injected TR5 was up to £985 (£1,260 13s 11d with tax), over £100 more than a six-cylinder MGC.

1968 Triumph TR5 PI front 3q © 2009 AlfvanBeem PD-AS
The Triumph TR5 PI looks almost identical to the TR4A, but the grille is different and there is no longer a hole for the external starter handle optional on the TR4 (although the notch for it below the grille remains). Under the bonnet, the radiator is mounted farther forward than on the four-cylinder cars to allow clearance for the longer six-cylinder engine. The TR5 PI is actually a bit lighter than a TR4A with independent rear suspension, but is slightly more nose-heavy. (Photo: “Triumph TR 5-PI 96-27-FR” © 2009 AlfvanBeem; dedicated to the public domain by the photographer under a Creative Commons CC0 1.0 Universal Public Domain Dedication, resized and modified 2012 by Aaron Severson)

The American press was less than ecstatic about the TR250, having been presented for the third time in seven years with a new and more expensive TR that was no faster than its predecessor. A few period reviews indicated that the TR250 was actually slower, although the disparity was probably attributable to the fact that the TR4’s optional 4.10 axle ratio was no longer offered except by special order. Either way, performance was not sufficient to keep reviewers from grousing about the overly familiar styling, dated body structure, and a suspension that still didn’t seem quite sorted. Owners soon complained about the emissions-controlled carburetors, which were temperamental and could not be adjusted.

The TR5 PI met a better reception abroad. If there were still doubts about the chassis, they were mostly compensated by the strong new engine. The injected six was much thirstier than the old four, demanded super-premium (100-101 RON) fuel, and had a rather rough idle, but endowed the TR5 with muscular performance. Despite a taller axle ratio, 0-60 mph (0-97 km/h) was now achievable in around 8 seconds and top speed with overdrive was close to 120 mph (193 km/h). That wasn’t fast enough to threaten an E-type Jaguar, but would administer a sound thrashing to almost any new car in the TR’s price range. The rival MGC, marginally more powerful on paper, was no match at all for the Triumph.

1968 Triumph TR5 PI rear 3q © 2009 Robotriot CC BY-SA 3.0 Unported
From the rear, the main distinguishing features of the Triumph TR5 PI are the exhausts (still duals, but with both outlets on the left rather one than on either side of the car), the “2500” badges on the rear fenders, and the backup lights (reversing lamps) beneath the taillights. This car’s luggage rack is not stock, nor are the wire wheels, a £38 6s 8d option on British cars. (Photo: “Triumph TR5 PI Heck” © 2009 Robotriot; resized and used under a Creative Commons Attribution-ShareAlike 3.0 Unported license)

From a reliability standpoint, however, American buyers may have been better off with the carbureted engine, as the injection system proved quite troublesome. In principle, it was not an overly complicated device (although even the Lucas development engineers thought the use of six separate butterflies was a mistake), but it required a level of manufacturing precision that was hard to achieve on an automotive assembly line or in a dealer service bay. A case in point was the metering diaphragm, whose springs had to be carefully matched to each unit and could not be adjusted; the service manual was full of stern injunctions not to tamper with them. The injectors themselves were designed for easy replacement, but the metering unit required an expert touch and Triumph preferred to replace the unit rather than attempt to repair or rebuild it. Owners were well advised to regularly change the fuel filter, which Triumph recommended every 12,000 miles (19,000 km), and to not let the fuel level drop too low, lest hard turns expose the pump pickup and allow air into the system. The pump seals could also give trouble.

The TR250 sold reasonably briskly in the U.S. — 8,484 units during its short run — but was well off the pace of the four-cylinder TR4. The six-cylinder car also commanded less loyalty than its predecessor; in a 1969 Road & Track owner survey, over 40% of TR250 owners said they wouldn’t buy another. The U.S. competitions department had no great luck with the TR250 either. The SCCA had reclassified the six-cylinder car in C Production, where it was simply outgunned.

The TR5 PI accounted for only 2,947 units, a sign of how important North America was to Triumph’s overall sales volume. Fewer than 1,200 TR5s went to the U.K., but that was actually considerably more than the yearly average for the TR4, which had always been rather scarce in the home market. The 2.5 PI engine found greater success in a different platform: In late 1968, Standard-Triumph installed a more mildly tuned version of the injected six in the 2000 saloon to create the sporty 2.5 PI, which outsold the TR5 by more than three to one.

SIDEBAR: The Triumph TR250K

Around the time the Triumph TR5 and TR250 debuted, Kas Kastner, Triumph’s U.S. competitions director, commissioned 30-year-old designer Peter Brock (of Cobra Daytona fame) to develop a radical new sports-racer body on a modified TR250 chassis.

Dubbed TR250K, the resultant car was a sleek, low-slung roadster standing only 43 inches (1,092 mm) high. Compared to its TR250 progenitor, the TR250K was stretched about 6 inches (152 mm) overall and the engine was moved about 9.5 inches (240 mm) farther back in the chassis, presumably to allow better weight distribution and a lower bonnet line. Despite being somewhat larger than a TR250 or TR4A, the TR250K’s aluminum body kept dry weight well under 1,600 lb (700 kg). Brakes were big Airheart discs all around. The engine was the new 2,498 cc (152 cu. in.) straight six, but with the recent merger between Leyland and Rover, Kastner hoped to substitute Rover’s ex-Buick aluminum V8, which would have been both lighter and more powerful than the six.

Bruce McWilliams, authorized the construction of a single prototype that Kastner entered in the 1968 12 Hours of Sebring, driven by Bob Tullius. Although the TR250K won widespread admiration for its radical styling, it did not finish the race, felled by wheel failure and suspension damage.

1968 Triumph TR250K side © 2008 Jeff Kyle per
The actual TR250K prototype, seen at Watkins Glen in 2008. The prototype has been repainted several times, but it is once again its original color or a close approximation thereof. (Photo: “1967 Triumph TR250K” © 2008 Jeff Kyle; used with permission)

Kastner tried hard to convince Standard-Triumph chairman George Turnbull to consider the TR250K as the basis for a future production TR, even getting the prototype on the covers of several prominent U.S. automotive magazines to drum up support. Nothing came of it; Kastner felt the factory had dismissed it because it wasn’t their idea, but McWilliams maintained that the TR250K simply wouldn’t have been suitable for production without being hopelessly watered down. Kastner and Peter Brock pitched another proposal to Spen King and British Leyland product planner Mike Carver in 1970, but that was not adopted either. However, Brock believed that the later TR7 owed a lot to the TR250K. (We don’t know if the TR250K had any direct influence on Harris Mann’s TR7 design, but the TR7 was influenced by Mann’s 1969 Zanda show car, which, although not resembling the TR250K in any specific way, had a similar aesthetic.)

A NEW BOTTLE: THE TRIUMPH TR6

With the TR5 PI/TR250, Triumph had belatedly managed to give the TR a new body, a new chassis, and a new engine. However, by the time all that was accomplished, the “new” body was six years old and no longer looked particularly new, a point Bruce McWilliams had made in strong terms during the development of the six-cylinder cars. In mid-1967, even before the TR250 and TR5 went on sale, Standard-Triumph decided that a further update was needed post-haste.

1970 Triumph TR6 badge
The Triumph TR6 looked like an all-new car, but was essentially a clever and elaborate facelift of the TR5 PI/TR250. (author photo)

Back in 1964, Triumph had developed a prototype called Fury, a Michelotti-styled convertible with fully independent suspension (similar to the layout subsequently adopted for the TR4A), a six-cylinder engine, and monocoque construction. Although the Fury was smaller than the TR4, it otherwise seemed a logical next step for the TR. Body-on-frame sports cars were already becoming somewhat old-fashioned, particularly after the arrival of the unitized MGB. However, switching to monocoque construction would have meant an all-new body structure, which was not yet feasible.

With the acquisition of Rover, Leyland was doing quite well, but its resources were already heavily committed to other projects, including a rethinking of the front-wheel-drive 1300 family car line (which resulted in the cheaper rear-wheel-drive Toledo and Dolomite), a facelift of the big saloons, and development of the new Stag, a V8-powered sports car to be lobbed in the general direction of the E-type Jaguar and W113 “Pagoda” Mercedes. A completely new TR was not an immediate priority, particularly since the existing car had already received an updated chassis and a new engine.

The alternative was an extensive makeover, enough to give the familiar package a fresh look without the expense of an all-new body. Ordinarily, Standard-Triumph would have turned to Michelotti for such a job, particularly since they wanted it done quickly, but Leyland and Triumph had more pressing need for his talents elsewhere, including the restyling of the 2000 and 2.5 PI saloons. The TR facelift was done instead by Gerhard Giesecke of the West German coachbuilder Karmann, which didn’t flinch at Triumph’s daunting deadline and offered a highly competitive price for both the restyling and tooling. Giesecke’s design, reportedly developed with considerable input from Triumph’s North American organization, went from clay to production in a little over a year and Leyland was very pleased with the results, earning Karmann the tooling contract for the 2000/2.5 PI Mk 2.

Triumph TR6 hardtop side © 2012 Peter Laurence (used with permission)
An early (pre-1972) North American Triumph TR6 hardtop. The new one-piece hardtop was one of the few elements of the TR6 not designed by Karmann: It was the work of Les Mann’s in-house styling team in Coventry. The TR4’s two-piece hardtop was expensive to manufacture and despite its novelty Triumph had never figured out how to merchandize it effectively, to the later regret of some company executives. Note the small pip ahead of the door, which is the ubiquitous blue British Leyland fender badge. (Photo: “Triumph TR6” © 2012 Peter Laurence; used with permission)

The result of Karmann’s efforts was the Triumph TR6, which replaced the TR5 and TR250 on the production line in late 1968. Like the original TR4 of seven years earlier, the TR6 was less new than its extensively revamped styling implied. Much of the tooling was new, as were the fenders, bonnet, grille, and front and rear clips, but from a structural standpoint, the TR6 was largely carryover. The new fenders made the body slightly longer than before, but the lack of bumper overriders (at least initially) trimmed overall length slightly to 155 inches (3,937 mm). Wheelbase and overall width were unchanged, but the addition of wider 5.5×15 wheels increased tread width to 50.25 inches (1,276 mm) front and 49.75 inches (1,264 mm) rear.

There were no major chassis changes for the TR6, but a front anti-roll bar was added and the spring and damping rates retuned in an effort to better balance ride and handling. (The anti-roll bar was the first on a production TR, although anti-roll bars had been on the competition parts list for years.) Also unchanged were the engines: the carbureted six for North American cars, the 2.5 PI engine for other markets, where the TR6 was typically badged “TR6 PI.”

1973 Triumph TR6 engine
The North American Triumph TR6 retained the TR250’s carbureted six, initially with an unchanged net output of 104 hp (78 kW) and 143 lb-ft (194 N-m) of torque. Non-California cars retained dual Zenith-Stromberg carburetors until the end of the model run in 1976, but stricter California emissions standards limited cars bound for that market to a single carburetor, with predictable effects on power. Even the 49-state cars became increasingly festooned with emissions-control devices throughout the TR6’s run, including exhaust gas recirculation and the air injection pump Triumph had previously avoided. Net power rose from 104 to to 106 hp (78 to 79 kW) in 1972, but net torque output fell by about 7%, to 133 lb-ft (180 N-m). (author photo)

The TR6 wasn’t substantially heavier than the TR5/TR250, so performance was — again — little changed. Road & Track‘s 1969 TR6 test car was almost dead even with their previous TR250 up to 100 mph (161 km/h), reaching 60 mph (97 km/h) in just under 11 seconds; top speed for carbureted cars was again in the 107-110 mph (172-176 km/h) range. The TR6 PI, meanwhile, could complete the 0-60 mph (0-97 km/h) run in just over 8 seconds and reach 118-120 mph (190-193 km/h) with overdrive. Reviewers found the TR6’s ride and handling more composed than the TR250’s, although the anti-roll bar made for pronounced understeer where the early TR4 would hang out its tail at will.

At home, the starting price of the injected TR6 was up £35 (about $84) to £1,020 (£1,333 19s 2d with tax). Thanks to the recent devaluation of the sterling, the U.S. TR6 was actually a bit cheaper than the TR250 at launch, starting at $3,275 POE. However, U.K. prices would escalate rapidly over the next few years, driving U.S. prices ever higher.

1973 Triumph TR6 front 3q
Aside from stripes and decals, one of the few obvious visual changes to the Triumph TR6 during its eight-year run was the addition of an under-bumper spoiler for 1973. The spoiler, which was always black regardless of body color, reportedly reduced front-end lift at speed, although that was becoming increasingly academic in the U.S. by this time. (author photo)

THE BMC-LEYLAND MERGER

By the time the TR6 debuted in January 1969, the U.K.’s Wilson government had coaxed Leyland into a merger with the larger but considerably less solvent British Motor Holdings, which included BMC (Austin, Morris, Riley, Wolseley, and various suppliers) and Jaguar. The chairman of the new British Leyland Motor Corporation was Leyland/Standard-Triumph boss Donald Stokes, who received a life peerage for his trouble. Consolidation and rationalization were not yet on the table, although they would follow soon enough, but the merger did mean a management shuffle, including the departure of Triumph general manager George Turnbull and technical director Harry Webster for Austin-Morris, replaced by Turnbull deputy Cliff Swindle and Rover’s C. Spencer King, respectively. Less happily, British Leyland also inherited BMC’s financial problems and ongoing labor disputes.

1973 Triumph TR6 rear 3q
U.S.-spec Triumph TR6s became progressively more gaudy throughout in the early seventies, adding cosmetic touches like the Union Jack decals on the rear fenders for 1973. This car’s roll bar, alloy wheels, and luggage rack were not standard equipment, of course, although the latter items may have been dealer accessories. Note the angular Kamm-style tail panel, which in a typically seventies touch was always painted black, regardless of body color. (author photo)

Around the time Spen King arrived, Triumph began development of successors for the GT6 and TR6, codenamed Lynx and Bullet respectively. The original plan was for the Bullet to debut by the 1973 model year in order to spare Triumph the expense of modifying the TR6 to comply with the new U.S. bumper standards, but for various reasons (discussed in more detail in our article on the TR7) that proved impossible. As a result, the TR6 ended up lasting far longer than intended: almost eight years rather than four or five.

Because a replacement was already in the works — and because money was becoming increasingly scarce — the TR6 enjoyed little additional development during the remainder of its life. Most of the changes it did receive were for either regulatory compliance or production rationalization, such as the addition of a lockable steering column for 1970 and the installation in mid-1971 of the stronger four-speed gearbox from the Stag. The Stag’s automatic transmission was apparently not considered, although by this stage, American buyers might have been receptive.

Carbureted TR6s picked up a few horsepower, but sacrificed some torque and a fair measure of driveability in the ongoing struggle to remain emissions compliant. Stricter standards forced California cars to rely on a single Stromberg carburetor, making them particularly anemic; we don’t know if British Leyland even quoted output figures, which were also omitted from contemporary MG brochures for similar reasons. Progressive reductions in compression ratio also played hob with fuel economy.

Leyland never tried to federalize the injected engine, both for cost reasons and because it remained a source of service headaches in other markets. However, the U.S. organization did eventually persuade the SCCA to homologate the Lucas system, making the TR6 more competitive in C Production. Unfortunately, the Triumph was still hard-pressed by the Datsun 240Z.

1975 or 1976 Triumph TR6 front 3q © 2008 Geoffrey Gallaway CC BY-SA 2.0 Generic
A late (1975 or 1976) North American Triumph TR6. The roll bar again is not standard, but the bulbous overriders were, increasing overall length to 162.1 inches (4,117 mm) and curb weight to around 2,450 lb (1,111 kg). The shimmed suspension also required some changes to the indicator lights. (Photo: “Triumph TR6” © 2008 Geoffrey Gallaway; used under a Creative Commons Attribution-ShareAlike 2.0 Generic license)

U.S. safety regulations were almost as problematic for Triumph as emissions standards. New roof crush standards were passed in 1971 that would have effectively outlawed convertibles and roadsters, although a federal district court judge eventually overturned that rule before it went into effect. Another challenge was the federal 5 mph (8 km/h) crash standards that took effect in 1973. Although sports cars received a one-year exemption, in mid-1974 Leyland was forced to add bulky and awkward-looking overriders to the bumpers of North American TR6s (and MGBs) and shim their suspensions to bring bumper height to the regulation level.

While the TR6 PI was spared those indignities, the injected cars eventually lost some of their teeth as well. For the 1973 model year, widespread complaints about the 2.5 PI engine’s rough idle prompted Rover-Triumph (the two organizations had recently merged) to substitute the shorter-duration camshaft from the federalized cars, which provided better low-speed behavior at the expense of peak output. Net output fell to 124 hp (93 kW) and 143 lb-ft (194 N-m) DIN. At the same time, all TR6s adopted the newer Laycock de Normanville J-type overdrive, which had a taller overdrive ratio and could no longer be used on second gear, a feature once beloved of rally drivers. A minor consolation was that the overdrive became standard on all TR6s in 1974.

1975 Triumph TR6 dash
The dashboard of a 1975 Triumph TR6 convertible. In the main, the interior of the TR6 changed little over the years, although there was a bewildering assortment of different seats (which reclined from late 1969 onward) and overdrive became standard from 1974. This car’s leather-wrapped wheel appears to be an aftermarket accessory. (author photo)

TR IN TWILIGHT

Contemporary critics who bothered to test the late Triumph TR6 conceded that it still had its charms, including rugged good looks and an entertaining basso profundo exhaust note, but in other respects, the Triumph seemed increasingly anachronistic. Although the independent suspension was as modern as any, the TR6’s handling was nothing special by the standards of the mid-1970s and the body-on-frame structure allowed more quiver and shudder than newer unitized rivals. The controls were heavy and there were assorted minor annoyances that reflected the age of the basic package. The rival Datsun 240Z felt much more modern and was faster than even an injected TR6. For about the same money as a TR6 PI, British buyers could also have a Ford Capri 3000 GT, which had a less-sophisticated suspension but comparable performance and greater practicality.

Despite all that, despite the consolidation of British Leyland’s U.S. dealer networks, despite a dismal 16.4 mpg (14.3 L/100 km) showing on the first Environmental Protection Agency fuel economy cycle, despite ongoing complaints about quality and dealer service, and despite a price tag that by 1975 was closing rapidly on $5,000, TR6 sales remained consistently strong. Even the ugly bumpers didn’t stop the TR6 from selling around 14,000 units in 1974, its peak year — a major percentage of Leyland’s North American sales.

The TR6 was still regularly seen on the racetrack as well. For 1975, the factory-sponsored teams reverted to carbureted engines and were reclassified in D Production, where the TR6 was far more competitive. Cars prepared by Bob Tullius’ factory-backed Group 44 team took the SCCA D Production national championship in both 1975 and 1976. The latter victory was somewhat awkward for British Leyland’s U.S. organization because the winning TR6, an ex-Group 44 car driven by actor Paul Newman, actually vanquished a new TR7 driven by Lee Mueller of Huffaker Engineering, Leyland’s West Coast team!

1975 Triumph TR6 rear
This is a 1975 North American Triumph TR6, but the present owner has apparently discarded the bumper overriders and, if our eyes don’t deceive us, the shims that would ordinarily raise the ride height. (author photo)

Had British Leyland been so inclined — and had unfavorable late-seventies exchange rates permitted — the TR6 could probably have survived at least until the introduction of the convertible TR7 in 1979, but it was not to be. Rover-Triumph was eager to drop the older Triumph six at the earliest opportunity, particularly the expensive and problematic 2.5 PI version; the TR7 would use Triumph’s slant-four “Saab engine” (with the Rover V8 to follow after launch) while the successor to the 2000/2.5 PI saloons, the Rover SD1, was slated to use an all-new, Triumph-developed OHC six. Delays with the latter, as well as British Leyland’s near-bankruptcy, kept the carbureted six alive in the big Triumph saloons until 1977, but the injected engine ceased production in the summer of 1975, also putting an end to both the 2.5 PI saloon and the TR6 PI. We assume that TR6 PI sales, which had never topped about 3,000 a year, did not justify substituting the carbureted six, although Rover-Triumph did install a carbureted version of the 2,498 cc (152 cu. in.) engine in the saloons.

The North American TR6 survived another year, but finally expired in July 1976, bringing production to 94,619 units. U.S. dealers were sad to see it go; the TR6 was an easier sale than the controversial new TR7 and had healthier profit margins to boot. The last TR6 off the line went to Bob Tullius, marking the end of an era.

GRANDFATHER’S AX

The late Triumph TR6s had shed almost every vestige of the original TR2 and TR3, but, like the old paradox of grandfather’s ax, it was still in some sense the same car, replaced bit by bit. Excepting the injected cars, which were really rather rare, the performance of the last TR6s was remarkably similar to that of their predecessors of 22 years earlier. The ride and brakes were better, there were windows instead of side curtains, and American buyers could even order air conditioning, but these were essentially refinements of the basic concept rather than a fundamental reinvention.

What had changed in the interim were Triumph’s customers. When the TR debuted, its central appeal was that it was a $2,500 sports car that could run with $4,500 Porsches and give a credible account of itself on a racetrack. Certainly, some TR6 owners raced their cars, as they had with the TR2, TR3, and TR4, but that was no longer the primary draw. In stock form, the TR6’s biggest selling points — at least in the U.S. — were its convertible top (a feature becoming very scarce in the North American market by the early seventies) and old-school flavor. It was retro years before that term was coined, a vivid relic of an era when rough-and-ready sports cars were the rule rather than the exception.

1968 Triumph TR250 front 3q
1975 Triumph TR6 front 3q
If you replace the head of the ax and then later replace the handle, is it still the same ax? It depends on your point of view — much like the differences between this TR250 and late North American TR6 (or, for that matter, the injected TR5 and TR6 PI). (author photos)

If the TR6 had become a sort of rolling nostalgia piece, more quaint than ferocious, that nostalgic appeal was also the main thing that kept it viable in its final years. Since the mid-sixties, Standard-Triumph executives like Mike Cook had recognized that the TR’s best defense against new threats like the American pony cars was to maintain its traditional character. Even if Leyland had been willing to finance an all-new unit-body sports coupe in the modern idiom, there was no guarantee that such a car would have been well received by buyers and it might well have alienated the TR’s existing audience. That is essentially what happened to the TR7: While it was more modern, more practical, and more comfortable than the TR6, most critics and many buyers felt the TR7 wasn’t fast enough, sporty enough, or pretty enough to compensate for the loss of the TR6’s torque, long-striding overdrive, or wind-in-the-hair joie de vivre.

Total production of the TR4/TR4A, TR5/TR250, and TR6 amounted to almost 175,000 units, well short of the cheaper Spitfire — which accounted for more than 314,000 units from 1962 to 1980 — and a fraction of the MGB’s tally, but still decent by Triumph standards (no pun intended). Interestingly, the federalized TR6 accounted for not only the lion’s share of TR6 production, but also close to half of all TRs built between 1961 and 1976, which says something about buyer priorities.

Considered another way, though, it makes perfect sense: The TR6, particularly the pre-1974 form, retained most of the virtues of earlier TRs while at least mitigating most of their worst shortcomings. If it was still a little crude and noisy, that was at least half the point, and if the stock performance wasn’t quite enough, there were ample ways to brighten it up. For a lot of people, those qualities are exactly what sports cars are all about.

# # #

ACKNOWLEDGMENTS

The author would like to thank Jeff Kyle and Peter Laurence for the use of their photos.


NOTES ON SOURCES

Our sources on the development of the Triumph TR family and on the travails of Standard-Triumph International during this period included Keith Adams, “Feature: Triumph TRs, 30 years on — The end of the line,” Octane October 2011, www.classicandperformancecar. com, accessed 3 January 2012; “All-independent TR4,” The Motor 13 March 1965, reprinted in Triumph TR4 – TR5 – TR250 1961-1968 (Brooklands Road Test Series), ed. R.M. Clarke (Cobham, England: Brooklands Books Ltd., ca. 1997), pp. 49-51; “A New Triumph TR Sports Car,” Cars Illustrated October 1961, reprinted in ibid, pp. 16-18; “A short history of Lucas Mk1 and Mk2 fuel /petrol injection” and “Triumph 2.5 P.I. Lucas Mk2 System” Lucas Injection, www.lucasinjection. com/, accessed 20 September 2012; “Auto Test: Ford Capri 3000 GXL,” Autocar 8 March 1973, reprinted in High Performance Capris: Gold Portfolio 1969-1987 (Cobham, England: Brooklands Books Ltd., ca. 1990), pp. 40-45; Sam Barer, “Triumph TR6 proves itself a reliable daily driver,” Sound Classics, reprinted at British Car Forum, n.d., www.britishcarforum. com/ files/ sammyb3.pdf, accessed 18 October 2012; John Blunsden, “TR4 on Test,” Motor Racing October 1961, reprinted in Triumph TR4 – TR5 – TR250 1961-1968, pp. 14-15; John Blunsden and John Sprinzel, “Coupe Winning TR4 on Test,” Motor Racing August 1962, reprinted in ibid, p. 37; “Boots and All Take No Notice of the Pictures: The TR5 Is All Male,” Car October 1967, reprinted in ibid, p. 78; Michael Cook, Triumph Cars in America (St. Paul, MN: MBI Publishing Co., 2001); Mike Covello, Standard Catalog of Imported Cars 1946-2002, Second Edition (Iola, WI: Krause Publications, 2001); James T. Crow, “Profile: Kas Kastner: ‘Anybody can give you romance, I can give you results,” Road & Track Vol. 29, No. 10 (June 1978), pp. 14-15, 18; “Design at BRE,” Brock Racing Enterprises, bre2. net, accessed 20 September 2012; Jim Donnelly, “Kas Kastner,” Hemmings Sports & Exotic Car #37 (September 2008), p. 60; “Enter, like a peal of thunder… Triumph’s petrol injected TR5,” Sports Car World October 1968, reprinted in Triumph TR4 – TR5 – TR250 1961-1968, pp. 90-93, 102; Edwin Storm’s Free Car Brochures website at the Old Car Manual Project (storm.oldcarmanualproject. com); Gregor Grant, “The Triumph TR4,” Autosport 14 September 1962, reprinted in ibid, pp. 38-39, and “The Triumph TR4A,” Autosport 10 September 1965, reprinted in ibid, pp. 70-71; Peter Garnier, “Around the Competition Departments, Part 3 – Standard-Triumph,” The Autocar 15 December 1961, reprinted in ibid, pp. 19-22; “Injection TR,” Motor 7 October 1967, pp. 54-57; “Invigorating Injection (Motor Road Test No. 19/68: Triumph TR5,” The Motor 4 May 1968, reprinted in Triumph TR4 – TR5 – TR250 1961-1968, pp. 79-84; Gordon Jennings, “At Sebring: Inside Triumph’s Triumph,” Road & Track Vol. 14, No. 10 (June 1963), reprinted in ibid, pp. 40-42, and “Kas Kastner and his Super Triumph: The car they couldn’t keep from winning,” Car & Driver Vol. 11, No. 8 (February 1966), pp. 48-49, 92; “Kas Kastner,” The Triumph Sports Six Club, n.d., www.tssc. org.uk, accessed 20 September 2012; R.W. Kastner, “Kas Kastner — Vintage Triumph Racing and More,” kaskastner. com, accessed 20 September 2012, and “P.I. Performance,” Triumph World April-May 2004, pp. 62-65; “Ken Miles and the editors of Car and Driver road test six sports roadsters,” Car and Driver September 1966, reprinted in Car and Driver on Datsun Z, 1600 & 2000 1966-84 (Brooklands Books), ed. R.M. Clarke (Cobham, England: Brooklands Books Ltd., ca. 1986), pp. 7-16; David Knowles, MG: The Untold Story (Osceola, WI: Motorboks International, 1997); William Krause, Triumph Sports Cars (Enthusiast Color Series) (Osceola, WI: MBI Publishing Company, 1998); David LaChance, “Rubery Owen,” Hemmings Sports & Exotic Car #78 (February 2012); Leon Mandel, “TR-250K: Salvation of an Empire,” Car & Driver Vol. 13, No. 10 (April 1968); Nicola Marras, “L’angolo della TR4: Group 44,” 2004, www.nicolamarras. it/ tr4/ group_44/ group_44.html, accessed 20 September 2012; Mark J. McCourt, “1968 Triumph TR250,” Hemmings Motor News January 2007; Bob McVay, “Triumph’s New TR4-A Features Semi-Swing Rear!” Motor Trend Vol. 18, No. 1 (January 1966), p. 53; “Multi-Purpose Triumph,” Road & Track Vol. 18, No. 6 (December 1966), pp. 92-94; Robert A. Myers, “Road & Track Owner Survey: Triumph TR4/4A/250,” Road & Track Vol. 20, No. 12 (August 1969); reprinted in Triumph TR4 – TR5 – TR250 1961-1968, pp. 99-102; “Opposed Valve Cylinder Head for Triumph TR3 and 4,” The Autocar 23 August 1963, reprinted in ibid, p. 48; Jan P. Norbye and Jim Dunne, “The $3,000 Roadsters,” Popular Science Vol. 195, No. 2 (August 1969), pp. 96-101; Terry O’Beirne, “History of 6 cyl Triumph engine,” Triumph Sports Owners Association Queensland Inc., www.tsoaq. org.au, accessed 25 October 2012; Harold Pace, Vintage American Road Racing Cars 1950-1970 (St. Paul, MN: Motorbooks International, 2004); David Phipps, “Triumph TR-4: A welcome new bundle from Britain,” Canadian Track & Traffic September 1961, reprinted in Triumph TR4 – TR5 – TR250 1961-1968, pp. 12-13; Bill Piggott, Triumph TR2 TR3 TR4 TR5 TR6 TR7 TR8 (Collector’s Originality Guide) (Minneapolis, MN: Motorbooks/MBI Publishing Co., 2009) and Original Triumph TR4/4A/5/6: The Restorer’s Guide (Osceola, WI: Motorbooks International, 2001); Productioncars. com, Book of Automobile Production and Sales Figures, 1945-2005 (N.p.: 2006); “Road Research Report: Triumph TR-4,” Car and Driver Vol. 7, No. 10 (April 1962), reprinted in Triumph TR4 – TR5 – TR250 1961-1968, pp. 25-30; “Road Research Report: Triumph TR-4A,” Car and Driver Vol. 10, No. 11 (May 1965), reprinted in ibid, pp. 61-68; “Road-Test Report on a Sports Car: The Fuel-Injection Triumph TR5 PI,” Motor Sport August 1968, reprinted in ibid, pp. 88-89; Graham Robson, The Triumph TRs: A Collector’s Guide, Second Edition (London: Motor Racing Publications Ltd., 1981); Graham Robson and Richard Langworth, Triumph Cars: The Complete Story, Second Edition (Pitlake, Croydon: Motor Racing Publications Ltd., 1979, 1988); Bill Sanders, “Triumph 250: Six Cylinders for ’68,” Motor Trend Vol. 20, No. 4 (April 1968), reprinted in Triumph TR4 – TR5 – TR250 1961-1968, pp. 86-87; “Sports Cars in Australia: TR4 Is Rugged, Fast and Stable,” Australian Motor Sports January 1965, reprinted in ibid, p. 69; Standard-Triumph Group, “Open up a whole new world of sports car driving!” [Triumph TR5 PI brochure 387/967/UK], c. September 1967, and “Take a good look at the hot new TR6 PI while you’ve got the chance” [advertisement, c. 1969]; Tim Suddard, “Rivals at Speed: MG vs. Triumph,” Classic Motorsports November 2005, www.classicmotorsports. net, accessed 25 October 2012; “The TR-4: It won its first medal standing still” [advertisement, c. November 1961], reprinted in Triumph TR4 – TR5 – TR250 1961-1968, p. 9; “The Triumph TR4,” Autosport 1 September 1961, reprinted in ibid, pp. 10-11; Wayne Thoms, “Race-Tuning the TR4,” Car and Driver Vol. 8, No. 2 (August 1962), reprinted in ibid, pp. 34-36; “TR-4 Street vs. Racing,” Car and Driver Vol. 9, No. 2 (August 1963), reprinted in ibid, pp. 44-47; “Triumph Before Tragedy: The Odyssey of the TR Sports Car,” Automobile Quarterly Vol. 28, No. 1 (1990), p. 29+; “Triumph Go All Independent,” Cars Illustrated April 1965, reprinted in Triumph TR4 – TR5 – TR250 1961-1968, pp. 52-53; “Triumph TR250,” Road & Track Vol. 19, No. 4 (December 1967), reprinted in ibid, pp. 75-77; “Triumph TR250 Road Test,” Road Test Annual 1968, reprinted in ibid, pp. 72-74; “Triumph TR4,” The Autocar 1 September 1961, reprinted in ibid, pp. 5-8; “Triumph TR6,” Car and Driver Vol. 14, No. 8 (February 1969), pp. 25-28, 84; “Triumph TR4: A Decade of Development (Road Test No. 26/62),” The Motor 11 July 1962, reprinted in Triumph TR4 – TR5 – TR250 1961-1968, pp. 31-33; “Triumph TR4A IRS (Autocar Road Test Number 2029),” The Autocar 28 May 1965, reprinted in ibid, pp. 55-60; “Triumph TR-4: How little does it cost to run a big sports car?” [advertisement, c. 1962], reprinted in ibid, p. 23; “Triumph TR-4: It takes more than bucket seats to make a sports car” [advertisement, c. 1965], reprinted in ibid, p. 54; “Triumph TR5 Petrol Injection,” Cars & Car Conversions September 1968, reprinted in ibid, pp. 94-96, 103; “Used Car Test 284: 1962 Triumph TR4,” Autocar 5 September 1968, reprinted in ibid, pp. 97-98; Roger Williams, How to Restore Triumph TR2, 3, 3A, 4 & 4A: Your step-by-step guide to body, trim and mechanical restoration (Dorchester: Veloce Publishing Ltd., 2009), How to Restore the Triumph: TR5/250 and TR6 (Dorchester, Veloce Publishing Ltd., 2001), and Triumph TR6: The Essential Buyer’s Guide (Dorchester: Veloce Publishing Ltd., 2006); and the Wikipedia® entries for the Triumph TR4 (en.wikipedia.org/wiki/Triumph_TR4, accessed 20 September 2012) and TR5 (en.wikipedia.org/wiki/Triumph_TR5, accessed 13 September 2012).

Additional information on British Leyland corporate politics, other Triumph models, rivals, and designer Giovanni Michelotti came from Keith Adams, “The cars: Triumph Herald/Vitesse,” AROnline, 4 July 2011, www.aronline. co.uk, accessed 4 January 2012, and “The cars: Triumph 2000/2500 development history,” AROnline, 29 August 2011, www.aronline. co.uk, accessed 10 January 2012; David Traver Adolphus, “Visionaries: Henry George Webster,” Hemmings Sports & Exotic Car #22 (June 2007), p. 60; “Autocar road test 1894: Porsche Super 90 1,582 c.c.,” Autocar 21 September 1962, reprinted in Porsche 956 Ultimate Portfolio, ed. R.M. Clarke (Cobham, England: Brooklands Books Ltd., ca. 2006), pp. 148-152; “Autocar road test No. 1956: Triumph 2000 1,998 c.c.,” Autocar 10 January 1964, pp. 66-70; “Autotest: Triumph 2000 Mk2 (1,998cc),” Autocar 16 October 1969, pp. 132-135; “Autotest: Triumph 2500S 2,498 c.c.,” Autocar 5 July 1975, pp. 25-29; Serge Bellu, “People in history: Giovanni Michelotti, a great free-spirited designer,” Auto & Design No. 154 (2005), p. 50; Griff Borgeson, “Pininfarina: Man, Myth, & Monopoly: Part One: The Early Years,” Road & Track Vol. 15, No. 4 (December 1963), pp. 34-39; Mike Cook, “Passing of a Pioneer,” Hemmings Sports & Exotic Car #20 (April 2007); “Giovanni Michelotti,” Triumph Sports Six Club, n.d., www.tssc. org.uk, accessed 9 January 2012; Edgardo Michelotti, “g m profile,” n.d., www.michelotti. com, accessed 9 January 2012; “Obituary: Lord Stokes,” The Guardian [London, U.K.], 21 July 2008, www.guardian. co.uk, accessed 20 September 2012; “Shaping up well (Motor Road Test No. 51/69: Triumph 2.5 PI Mk. II),” The Motor 25 October 1969, pp. 27-32; “The M.G. A 1600 Two-Seater,” The Motor 2 September 1959, pp. 86-89; and Jonathan Wood, “Obituary: Sir George Turnbull,” The Independent [London, U.K.] 24 December 1992, www.independent. co.uk, 13 October 2012.

Some additional background on the Dové GTR4 came from information cards entitled “The Dove Story” and “6285PG Provenance” that appeared with a surviving car at the 2010 Pershore Plum Festival Classic Car Show; Steve Dival, “The Dove GTR4,” TR Drivers, 2003, www.trdrivers. com/ the_dove_gtr4.html, accessed 18 October 2012; David LaChance, “Caged Dove,” Hemmings Sports & Exotic Car #79 (March 2012); and “Two Syllables: 1963 Dové GTR4 Hardtop,” Bring a Trailer, 13 December 2010, bringatrailer. com, accessed 18 October 2012.

Some exchange rates for the dollar and the sterling were estimated based on Lawrence H. Officer, “Exchange Rates Between the United States Dollar and Forty-one Currencies,” Measuring Worth, 2011-2012, http://www.measuringworth.org/exchangeglobal/, used with permission). Exchange rate values cited in the text represent the approximate equivalency of British and U.S. currency at the time, not contemporary U.S. suggested retail prices, which are listed separately. Please note that all exchange rate equivalencies cited in the text are approximate, provided solely for the reader’s general reference; this is an automotive history, not a treatise on currency trading or the value of money, and nothing in this article should be taken as financial advice of any kind!


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6 Comments

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  1. what engines will fit my 72 tr6? id like to
    put an early Toyota Corolla(DXL) or Nissan
    (Datsun)?????
    PLEASE HELP!

    1. Judy,

      I omitted your phone number — if you really want, I can put it back, but generally posting your phone number online is asking for trouble. If anyone wants to reach you, they can contact me via the contact form and I will forward their information to you.

  2. Thanks very much for your well-researched article. It brought back many happy memories of my all too brief years with my restored 1967 TR4A IRS. I’ve often fantasized about tracking down and importing a TR5, but your description of the overly fussy PI has driven the last nail in that coffin.

    1. A lot of mechanical injection systems are fairly fussy things, at least in street car applications. The big problem, from an ownership standpoint, is having someone who knows how to work on it when necessary. That can be a big headache with a system not ever sold in the U.S.

  3. Did I miss mention of the TR6 PI listed in the title link?

    1. It is described in the text (it’s not in the title, but the title was already getting long). However, the TR6 PI was in most mechanical respects a TR5 PI with the restyled body. There were some mechanical changes to rationalize production with the 2.5 PI and to back off on the cam timing for a smoother idle, at the cost of some power.

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