Triumph TR7
Published: 26th Feb 2014 - 0 Comments - Be the first, contribute now!
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Do you drive this great classic or are thinking of buying one? Here’s how to ensure that you get the best out of your car for years to come
Shock horror! The TR7 is actually a decent sports car and this much maligned GT has a lot going for it 32 years since it was axed. True, the Rover-powered TR8 is something else again but there’s a lot you can do to tune and improve the basic 2-litre as this feature shows with the help of leading TR7 specialist Robsport International (01763 262263) who deals in all types of work for this Triumph as well as making certain parts. S&S Preparations (01706874874) is another expert.
1 ENGINE OUTPUT
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The engine is a halfway house Dolomite Sprint using an eight valve head and while you can fit the 16V top end, a simpler method to gain Sprint power is by head and cam upgrades. With re-jetting the SU carbs, up to 110bhp is attainable, or 120bhp with twin Weber DCOEs yet with more flexibility over the 16V. A budget tune consisting of a sportier exhaust manifold and K&N air filters works well for under £400 from Robsport, topped by a session on a rolling road, we suggest.
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It’s half a Stag engine which means similar head problems. A rubberized-type of gasket was originally planned but BL’s accountants wouldn’t have it. TR7 specialists such as Robsport of Hertfordshire http://www.robsport.co.uk can supply British Gasket alternatives which are an improvement so, if you’re rebuilding your engine, one of these is well worth fitting. You should also always use a rust-inhibitor coolant to stave off corrosion and the resultant clogging of the waterways as these engines are prone to overheating.
2 BOTTOM END
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In the real world the 2-litre engine in eight valve tune developed not much more than 95bhp so don’t believe the brochures! There’s not a great deal of ‘stretch’ to the engine apart from the usual rebore allowances to around 2100cc but it may be worth going for to gain a bit more torque. While it looks enough similar to an 1850 Dolomite unit, manifolds and other parts differ. The long timing chain is quite rattle-prone after the miles mount up although it doesn’t slip like the Stag’s.
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Crank end float isn’t a problem on these Triumph units which is good news although when rebuilding pay particular attention to clearing out the water ways; sump can’t be dropped in situ. V8 conversion kits are available and popular but it costs more than you think to do it properly. The Saab engine which originally was Triumph Dolomite is not the same engine anymore and won’t fit without drastic alterations.
3 STEERING AND SUSPENSION
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For a sports car, the TR7 was softly sprung so uprated dampers and springs are a priority. Even if you like it as standard, most drivers would appreciate the ‘anti-dive’, kit marketed by Robsport. These are simple blocks which fit between the anti-roll bar and crossmember and lower its angle to give a more even keel under braking. Polybushing tightens the chassis up well. More extreme mods include Ford Sierra top mount bearings for the front struts which improve the steering as well as making it a bit lighter.
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A simple but effective design; damper, spring and mounting bushes usually go, especially the front shockers. Harder polybush ones last a lot longer. Rattling steering columns due to worn bushes. Sloppy steering is usually down to the column couplings wearing out. It’s not a Dolomite-derived suspension but a design that was to be shared by the Dolomite’s replacement and so not interchangable parts-wise.
4 TRANSMISSION
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Soon after the TR7’s introduction, a better five-speed gearbox was made optional – it’s the Rover SD1-derived unit. In absolute terms however, the original four-speed gearbox cars (which are now becoming more collectable, incidentally) feel a bit faster due to the four-speed ratios being stacked closer together. However, if you’re doing lots of motorway driving, the five-speed box is the better bet. A heavier duty rear axle was provided for the five-speed and TR8s and can be utilised on lesser models.
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The original TR7 4-speed transmission featured a Marina/Dolomite sourced unit. Most featured the Rover SD1 ‘77mm’ five-speeder which apart from being slicker is also sturdier, although worn synchros (watch for gear clash) on second and third are pretty common as miles mount up. The three-speed Borg Warner automatic, while hardly sporting, is generally very reliable and doesn’t detract from the Triumph’s GT appeal too much.
5 BRAKES
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If the system is in good order and an anti-dive suspension kit is fitted (it costs under £30), then the brakes may well suffice. If you need new pads, then a change to EBC Greenstuff is well worthwhile even if you don’t drive fast and inexpensive when compared to off-the-shelf replacements. Uprated callipers, which can be sourced from the Capri 2.8, TR8 or the Rover SD1, are a cheap upgrade but needs mods to fit, or you can opt for a superior nut and bolt four pot brake kit such as Wilwood.
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Rear set up not Dolomite derived but apart from usual servicing holds no real worries. Rear discs can be grafted on; Lancs-based S&S Preparations has a kit, but you need the complete axle so is it really needed? Five-speed cars have better rear brakes anyway.
6 WHEELS AND TYRES
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As standard the TR7 ran on 165 x13 wheels and 175 or 185/70 tyres. These days, it’s not uncommon to see cars rolling on 14inch alloys and in fact it’s essential if much bigger brakes are fitted. If you use Capri anchors, wheel spacers may be needed. A move up to 14 inch wheels not only allows a much wider choice of rims and tyre sizes but it’s the icing on the cake to making a TR7 handle extremely well, claim the experts. Believe it or not, but MGF wheels fit Dolly/TR7 hubs and a low cost mod. A power steering kit costs £1320.
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Original plain steel wheels are usually swapped for alloys. Fitting poly bushes all round, on convertibles in particular, can make the ride too harsh, so you might want to stick with normal OE-spec rubber bushes, certainly in key areas. If the steering is too heavy once fatter tyres are fitted, consider aforementioned Ford Sierra top mount mod or a tailored power steering kit.
7 TRIM
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As standard, the TR7 boasts an excellent cockpit that’s even better than later MGF – the trouble is that it didn’t age well. Ratty trim is common and there are few really showroom condition cars left. Happily Robsport is remaking an increasing number of trim parts and accessories. Sunroofs, either glass porthole or sliding fabric, were popular and make cockpit more airy although, these days, ‘solid’ roofed coupés are more sought after.
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Various styles and types of trim were tried and some like the tartan seat pattern on later models even though it’s hard to replicate now meaning a lot run around with naff seat covers to hide the deterioration. The TR7 is a lot more watertight than early TRs, and this includes the convertibles if the hood is of good quality. As always, regularly inspect the rag top for wear, damage and ageing – many didn’t fit particularly well when new.
8 BODY AND CHASSIS
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Apart from certain custom mods there’s not a lot that you can do to improve the looks of the TR7 although some, like the Janspeed racer added rear buttresses. Certain colours to disguise the swage line and those MGB-like rubber bumpers helps the looks – some owners used to fit a boot mounted spoiler to balance the looks. We’ve seen some examples sporting a vinyl roof, while BL works rally car look is good. As far as we know you can’t convert coupé to a rag top.
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Rust is the main concern. The major rot areas are the chassis rails, floorpan, bulkheads and inner front wings, especially at the strut top mounts. Other major areas include the A posts and rear suspension pick-up points, all worth keeping an eye on. Sills are a real worry as they comprise of an inner, outer and strengthening panel (the latter on the rag top), again regularly check. Those huge bumpers mask valance rot and can droop, or drop off if their glued mounts fail.
9 DETAILS
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Later post 1977 TR7s are technically identified by a garland replacing TR7 transfer on the snout. Speke cars were built from 1974-1978 and were made of better materials, but sadly build quality was lower. Better, more powerful headlamps are well worth fitting. And like all ‘pop up’ headlamped cars, flashing the lights as a warning seems to take an age to take effect – consider fitting additional driving lamps under the front bumper if it unduly bothers you.
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The fuse box is located in glove box and rarely gives trouble but the electrically-operated headlamps can do. Contrary to popular opinion, it’s generally not the motors which fail but more down to dodgy electrical wiring and contacts that can collect road dirt and damage. Apart from Marina switchgear and stalks, there’s not a great deal carried over from other BL products.
SERVICING DATA
ENGINE OIL: Approx. 8 pints (4.5 litres), including filter
GEARBOX: Four-speed manual gearbox SAE 90 EP; capacity approx 2 pints (1.1 litres). For five-speed SAE xx EP; capacity 2.7 pints (1.5 litres)
N.B. For If the gearbox is completely drained, Triumph recommended it must be refilled with Hypoid 75W gear oil (best speak to a TR7 specialist about this)
REAR AXLE: SAE 90 EP oil; 2.25 pints (1.3 litres) for four-speed manual gearbox; 1.6 pints (0.9 litres) for five-speed
COOLING SYSTEM: 13 pints
SPARK PLUGS: Champion N12Y or equivalent. 0.024 - 0.026in
CONTACT POINTS: 0.014in - 0.016in
IGNITION TIMING: 10 degrees BTDC static (vacuum hose disconnected)
TAPPETS: Inlet, 0.008in (0.20mm.), exhaust, 0.018in
AND ANOTHER THING…
It’s not necessary to go down the V8 route if you want more from your TR7! Veloce Publishing has a very good book on tuning and improving TR7s as part of its Speed ‘Pro Series’. Another ‘must’ is the new definitive DVD on the history of the TR7 by TR Drivers Club member and TR7 expert John Clancey. A comprehensive four hour viewing, it dispels many of the myths and general misinformation that has dogged this car for years, with interviews on those who played a major role in the car’s design – many speaking out for the first time!
Classic Motoring
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