TR6 (1969 - 1976)
A design that began life as the TR4 in the early sixties evolving progressively through the TR4A (addition of independent rear suspension - IRS) and the TR5 (or 250 in the US) with the engine upgraded to the 2.5 litre straight six from 2.2 four and petrol injection (PI) added for the non US market place. The TR6 was launched in 1969 with the basic package comprising;
- Separate chassis
- Independent suspension all around (at the rear by semi-trailing arms and at the front by wishbones, both ends featuring the usual lever arm type dampers).
- 150BHP mechanically fuel injected 2.5 litre straight 6 featuring cast iron block & head motor. (1973 on cars being given a less lumpy cam and a rating of 125BHP in order to civilise their low end running characteristics).
- 4 speed plus overdrive (on 3rd and 4th) gearbox.
- Disc brakes at the front, drums at the rear
Most "cognoscenti" would no doubt confirm that the TR6 could be considered to represent the zenith of the marque's development, a "proper" British sports car in all respects. Designed by Karman of Germany, utilising the TR4 / 5's doors and inner tub to keep costs down, but with completely revamped front and rear outer body sections, gave the instantly recognisable and very masculine "classic" profile which has matured so well over the years.
TR7 (1974 - 1981)
The car built by British Leyland as the successor to the mighty TR6, with an overwhelming focus on the then perceived requirements of the all important mid-70's US market. The 7' was designed in-house (Triumph by this time having been absorbed into the British Leyland conglomerate) by Harris Mann (probably after having consumed too much cheese one night) with the "Wedge" being touted as British Leyland's "shape of things to come" which I suppose it was in various other forms.
The 7's design was a complete departure from all that had gone before, utilising modern unitary (or monocoque) construction and;
- McPherson strut front suspension
- Live rear axle and trailing arm rear suspension arrangement.
- 105bhp single overhead cam, twin carb'd 4 cylinder engine with cast iron block and aluminium head (the "slant 4" as sold to Saab for use in their 99 model)
- 5 speed gearbox (launched with a problematic 4 speed)
- Disc front brakes, drum rears.
The 7's most important departure from the tried and trusted TR formula though, was that it was not initially offered as a convertible at its launch in 1974 - a heresy that took until 1980 (79 in the States) to overcome. Its adoption of the 2 litre 8 valve slant 4 motor was also a bit on the disappointing side for a "serious" sports car.
It would also be true to say that the car was significantly compromised at its birth by a fatal combination of poor (non-existent?) quality control, political dogma (UK Trades Union and Corporate Management clashes) and the supposed impending US design legislation.
The TR7 really was the car that "almost was", with the 16V 4 cylinder variant never making it beyond the development stage and the V8 TR8 being produced just too late and in too few numbers to save it (the 8' now being perhaps being the most sought after TR of all).
The TR7 had a dreadful reputation, (I owned a late 70's Speke built example when I lived in the UK in the early 80's, it never broke down but it did dissolve very rapidly) but despite this, it outsold every previous TR model produced and eventually matured from the "ugly duckling" hard top piece of cheese (which in today's market appears remarkably fresh) to the sleek drop head pictured above.
A Sharper 7'
I suppose it's important to point out at this stage that our 6' is a completely standard "concourse queen" and remains totally unmolested (Lynne having forbidden medling as it is her car), whilst the 7' has been progressively "improved" over several years of ownership to meet my own personal definition of what a 2 litre 4 cylinder TR sports car should be. Sharp handling, well braked and quick. Such improvements comprising;
The 7 retains its 2 litre 8 valve unit, improved via the fitment of;
- Stage 3 polished and ported cylinder head (from S&S Performance in the UK).
- Competition cam & Heavy duty valve springs (supplied by S&S with the head)
- Twin 1.75 inch SU HS6 carbs replaced by twin Weber 45 DCOE's.
- Opto-Electronic ignition.
- Oil cooler.
- High output coil and low impedance HT leads.
- Stainless steel extractor manifold and large bore exhaust system.
The above package manages to wring a highly useable 110 - 120BHP (depending upon who's dyno its attached to) output at the rear wheels - 130 at the crank??. Unlike a standard 7', this car enjoys being rev'd hard.
Chassis & Running Gear;
- Koni dampers installed all around with lowered and stiffened springs
- 6 x 14 alloy mini-lite replica wheels fitted
- Ventilated discs and 4 piston callipers installed at front (in lieu of the weedy solid discs and opposed piston callipers of the original set up).
- Aeroquip braided stainless steel covered flexible brake hoses installed all around (no expanding rubber brake hoses to spoil feel).
- K-Mac castor / camber adjustment system installed to front struts, c/w strut brace. (These are best improvement you can make to a TR7)
- Anti-dive blocks installed to front anti-roll bar.
When we purchased the 7' in 99' its original interior was already long gone and its replacement was starting to look a bit tired. Having come into some cash a year or two after purchase, we opted to go the whole hog - ink blue Connolly hide was fitted to mimic the interior of the high spec Grinall V8 conversions. The seats were subtly reprofiled for better location laterally and pneumatically adjustable lumber supports installed. This was an expensive undertaking, but well worth it if you intend to keep the car for a number of years, as it still looks as good (better?) today than it did 5 years ago!
So, having made a not inconsiderable investment in the 7, just how does it compare to the bog standard 6?
The 7's Engine Bay
(Not quite as manufactured by BL in October 1981)
Weber 45's & K&N's
K-Mak castor / camber adjusters etc etc etc....
|The 6's bog stock engine bay |
(Better than built by BL?)
The upgraded 7' wins this comparison hands down - and so it should given the improvements made!
The 6's brakes over heat rapidly and suffer consequent premature fade when negotiating steep twisting downhill grades (just as the 7's did prior to being upgraded) or repeated braking from high speed, which can be quite un-nerving. Reports from other 6 pilots indicate that better pads could yield a discernible improvement in this department - (bring on the EBC Green Stuff). If the 7' was fitted with its original brakes, I think its lower weight and centre of gravity would make it a close run thing in terms of who could stop before hitting the car in front.
The 7' is capable of carrying far higher cornering speeds than the 6 given a smooth surface, but once again, given the mods made, so it should. If the surface is "poor" (and lets face it, they usually are) then the independent rear suspension of the 6' coupled with a far more supple ride allows it to achieve much better traction on exit than the 7, which tends to suffer from axle tramp as the wheels scrabble for traction. A different horse for a different course! The 6 always feels long, tall and narrow the 7' wide low and short.
The 6' has a very traditional understeer built into it, probably as a result of the weight of that cast iron 6 cylinder lump sat way out in front of the driver. It is never vague and uncommunicative, it just lets you know how long, thin and comparatively "tall" the car is.
Comparatively, the 7's steering wouldn't feel out of place on a go-kart. The original long travel mushy springs and "dampers" having been junked in favour of a much tighter / lower set up at the front, coupled with K-Mac castor / camber adjusters further enhanced with anti-dive preload blocks under the front anti-roll bar, combine to give a very precise degree of feel to accurately point the car where the driver would like it to go.
The bog standard 6' must take this round as this particular 7' has been tailored for a "firm" sporting ride, with minimal compromise for comfort (although it does remain reasonably civilised for road use). The 6' has considerably more suspension travel to play with compared to the (modified) 7, thus endowing the car with far more tolerance of poor surfaces than the taught 7. A standard 7' however is a different matter, with long travel (read mushy) suspension, with ride characteristics tailored primarily for the American market; its handling could be favourably compared with that of a small wedge shaped hovercraft.
The 6' also wins this round - the straight six engine providing lots of low down torque, with the 7's smaller, now more highly strung 4 cylinder power unit being unable to compete with the ‘beef' offered by the 6.
The 6' is fitted with a synchromesh 4 speed plus overdrive gearbox, giving (in effect) a fairly close ratio 6 speed unit. The action (on our 6 at least) is of a very precise "rifle bolt" nature, that doesn't tolerate indecisiveness when crossing the gate. The overdrive facility being a true joy to use; accelerating hard when overtaking through third and then third overdrive gives a real rush. No declutching or relaxation on the accelerator, just hold it flat and wait for the red line to arrive, then hit the O/D switch and the beast lunges forward again. All accompanied by that straight 6 exhaust note; Marvellous! Overdrive top providing a relaxed gait for longer trips.
The 7' has the good old BL 77mm gearbox installed as fitted to the SD1 V8. It features 5 gears in total with no electrically controlled overdrive facility (although overdrive was offered as a private option on some very early 4 speed 7's). The gears (other than 5th) are quite nicely spaced for the output of the 2 litre engine, with 5th being on the tall side for easy long distance cruising. (Although it is worth noting that the non-standard 14" wheels on my car have raised the gearing by about 10% which exaggerate this effect a little).
The 7' box's action is comparatively lax and a fair bit more tolerant than that of the 6. It has quite a long "throw" compared to the 6, but you can run up and down it with little drama, which is useful given the somewhat "peaky" nature of the tuned motor. I also remember from my ownership of a 5 speed 7 in the UK 20 odd years ago that first to second could be a bit reluctant on cold mornings due to the gearbox oil being a little thick. I can report that this is not an obvious issue when living in Brisbane however.
Comfort & Appointments
|The 7's interior (also not as supplied by BL in 1981). |
Ink blue Connolly hide, subtly re-profiled seats and pneumatic lumber supports ensure occupant comfort and safety. (See Stuart at "All Car Interiors" Lutwyche if you'd like one similar).
Comfort is the TR7's ace card in this contest, with the level offered by the "modern" 7' in terms of overall interior space, seat design and general ergonomics being much improved on that offered by the "classic" 6, making longer trips that much easier to bear in the 7'.
|The 6's interior (almost as supplied by BL in 1972). As traditional as a Chippendale chair (and just about as comfortable). |
(Motolita steering wheel being the only none original fixture here)
The aerodynamics of the 7 also ensure a much smoother "topless" ride than in the "sit up and beg" 6, who's upright windscreen generates a considerable amount of turbulence for both driver and passenger alike at even fairly moderate speeds.
The 7's acutely raked wind cheating screen and low sloping bonnet line coupled with low slung seating ensure minimal disturbance to the air flow over the car and therefore a much easier time for the car's occupants.
The 7's Cockpit - No original fitment tartan interiors here!
The 6's Office.
Should one drive this in carpet slippers and smoking jacket?
These two shots clearly show the major difference in the genetic makeup of these 2 TR's.
Is usability a high assessment criterion given that both these cars aren't that frequently used and when they are, they are both used solely for "pleasure"?
Let's assume that we have to drive them as our "daily transport" and then consider how they compare;
Both cars feature about the same luggage carrying capacity (although the 6 does have a very useful stowage area behind the seats), both cars are strictly 2 seaters, both have easy to use soft tops - hmmm tough call, but I'd say the 7' just pips 6' in the "usability" department (especially if its summer and the heat is causing the 6's fuel injection system problems with vaporisation!) as the more modern design is just that little bit more easy to live with.
The Classic Car scenes "X Factor" simply oozes from every nook and cranny of the 6, from its chrome wire wheels to its twin tail pipes and grunty 6 pot engine, all topped off by the best sounding exhaust note in TR history (Sorry - the throb of the V8 in the TR8 is just too American for me). A true British Bull Dog if ever there was one.
No matter how hard it tries, the 7 will never capture the 6's kudos in this (perhaps most important) regard as its just too "modern", with its rubber bumpers, unitary construction and civilised accommodation.
Interestingly, the 7' appears to be now well accepted as a paid up member of the venerable TR family, which perhaps 10 years ago was certainly not the case, whilst its aesthetics have aged very gracefully indeed over the 25 years since it was discontinued.
What was once considered "outrageous" or at best "radical" in terms of styling is now simply considered "TR7" by TR enthusiasts. Some people refer to the DHC (drop head coupe) version as the ultimate "hairdresser's conveyance" but I'd argue otherwise. With some careful upspec'ing a 7 (even a 2 lite one) can be given an "edge"
Pick one - OK the 6 has it (but the 7' has a sentimental attachment for me personally that the 6 doesn't (so Lynne, please don't ask me to choose).