Triumph TR4/4A

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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 ye

When you think about it, the TR4 sports the best of both worlds; the charm and nostalgia of the earlier TRs – but with the macho looks of the TR5 PI. This Triumph sports car is super easy to maintain and improve at home and you couldn’t wish for better back up and support from both the many owners’ clubs and the army of specialists. However, despite the car’s well proven and utterly orthodox design and construction, there’s a surprising number of pitfalls owners need to be aware of before you can spanner away in safety. Here’s our top tips…

1. Front suspension

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Uprated dampers and springs are mandatory. Revington TR sells various upgrades, with a full suspension rebuild (including new poly bushes, springs, dampers and anti-roll bar etc.) costing around £1700. A TR6-type anti-roll bar is an easy cheap mod but some say the benefits aren’t hugely significant unlike a full geometry reset coupled with fitting polyurethane bushes all round at the same time.

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Front trunnions need periodic lubrication or you risk a dangerous seizure; ideally, it should be EP90 gear oil, not grease, but the latter is far easier to handle with a gun.

Lower suspension wishbone mounting brackets are known to fall off so keep a regular eye on them. Springs known to sag which might sound advantageous, but tuners don’t really advocate altering the ride height for normal road use.

2. Brakes

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Improved DBA (Disc Brake Australia) or EBC’s wide range of performance discs equipped or EBC (or Mintex Classic) pads are good inexpensive mods at less than £150. Uprated callipers are next but not really vital unless engine is highly tuned or you envisage track work. Rear drums are adequate for all but the most extreme of uses, with just the addition of sportier linings, before opting for alloy Alfin drums to quell any fade.

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Strange but true – these earlier TRs wore disc brakes which are actually larger than the later TR5/6 set-ups – so opting for fuel injection hardware is a retrograde step! The rest of the brake design up poses no particular problems apart from routine service work – change the fluid at recommended intervals, of course, and swap flexible hoses with braided type for better pedal feel when the time comes.

3. Bottom end

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Wet liner block is easy to stretch; TRGB sells an 89mm piston and liner kit for 2.3-litres, costing £450 while TR Enterprises trumps this with a 92mm kit giving 2.5-litres, to provide TR6-beating torque although going above 2.3-litres isn’t warranted for road use. As a racing engine a lot of work is demanded to top 160bhp reliably because, the standard unit is not up to the job, so needs a steel crank, conrods and so on.

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Engine design means the bores can be simply re-sleeved, resulting in an almost open-ended engine life; it’s a bodge, but you can even rotate the liners to counter wear at the ‘thrust’ side. To prevent liners popping out with head off you need special clamp-down tool before you can turn crank. 60-70lb oil pressure shows good health but watch for oil leaks at rear of crank scroll seal, TRGB’s modern oil seal kit at £60 is advisable to cure this.

4. Engine output

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This unit may have also powered tractors but the ‘four’ can muster around 130bhp for reliable road use starting with a cheap session on the rolling road, paying attention to optimum mixture and ignition settings with better air cleaners, before a sportier exhaust; twin 1.75 SUs are ample for up to 130bhp before switching to Weber DCOEs. For whopping power hikes of up to 40 per cent go for a £3500 supercharger kit although ensure the engine is up to it first!

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Engine ideally needs unleaded additive or converting with hardened guides, as many experts reckon this four pot was somewhat under-cooled when new, leading to head gasket woes. An uprated radiator, with perhaps an electric fan for good measure, is a wise step, certainly if you intend to increase the horsepower or take on some long hot touring drives during 2018. Engines (stock or performance) cost £2000-£10,000 depending upon whether ready to go or as a DIY kit.

5. Steering & wheels

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Rack and pinion for the TR4, if in good order then it’s perfectly good enough in standard trim; speak to specialists involved in competition if you want a quicker, higher ratio rack – Revington TR sells them at just under £200. This will make the steering even heavier so consider power steering. The modern route is via Litesteer or EZ for a controllable electric set up although a conventional system pinched from a 2000/2500 can be adapted, so we’re told.

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Revington says its replacement steering racks are newly manufactured – and not recons – to the standard 3.125 turns from lock-to lock at just under £150 (it also markets a rack conversion kit for earlier TRs at £682, incidentally). As we eluded to earlier, the chassis geometry is highly critical for such an old design and should be set up by a known TR expert as, along with poly bushing, is said to be best £500 you’ll ever spend to make the car handle at its best.

6. Transmission

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Yes five-speeds are wonderful but don’t instantly dismiss the old fashioned overdrive as it potentially offers seven-speeds and comes into its own for tight hairpin rally roads after some uprating. The Rover LT77, Ford Sierra or a Toyota Supra fivespeed ’boxes can be installed; Revington offers a Toyota Supra conversion at some £4500 – it’s pricey we agree but the swap can be reversed back to original spec without any evidence. Flywheels can be lightened to aid throttle response; start with the already lighter 4A one, if possible.

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Infamous Triumph crankshaft thrust washer wear is still a problem. You need to watch crank pulley movement at the front of engine as the clutch is operated by an aid – if above 0.015in of play they can fall out. Oversized thrust washers can cure this plus, as sump can be easily removed, can also be done with engine in situ, but if bad, more involved repairs calls for a stripdown. Layshaft woes not unknown and overdrive units suffer from oil leaks and solenoid problems but it’s a sturdy unit generally.

7. Rear end

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IRS adds 100lb to TR4A’s weight and another reason why competition drivers prefer simpler earlier, more controllable rear end although TR experts say it’s not worth the expense and effort to swap unless fitting new chassis anyway. Adapting to telescopic damping pretty involved as well as costly but usually essential on TR4A for competition driving although you need to watch FIA regs. As with Stag, you can install a tailored BMW diff that’s a bolt on kit but it costs some £2000.

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Axles are sturdy but known to leak; full rebuild costs over £1000. Infamous Triumph spline lock affects 4A. Again FIA mods allows certain mods but for road use you can opt for modified driveshafts, although keeping a close eye on them and their u/js (all six of them) also helps reduce that ‘TR twitch’. SC Parts has modern CV driveshafts that are said to cure TR twitch and improve handling: £530 with hub.

8. Body and chassis

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CTM Engineering based in Southampton specialises in repairs or new chassis frames. Remember, a new chassis not only rids you of rust problems but it will be much stiffer and aid rigidity, talking of which, TR Enterprises sells a chassis stiffening kit for just £75 although the company adds that you need to decide how much you want to add before altering suspension settings – a roll cage also adds rigidity but too much of it spoils a TR’s handling.

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Outriggers rot badly and cost an easy £2000 because the body ideally needs to be removed, which is not a bad idea if major repairs are on the cards anyway. The front end hides a lot of nasties while reinforcing the differential and the trailing arms is not only a good move but essential if you contemplate converting the dampers to modern telescopic affairs. Rust around the rear diff area is common on As and can, if bad, lead to the unit tearing itself away from chassis, on hard driven cars!

And another thing…

Of the rare exotic delightful Dove… Doves of Wimbledon was a Triumph distributor but did not undertake the actual coachbuilt conversion but instead commissioned that work with Thomas Harrington Limited, a long established coachbuilder based in Hove, Sussex who was, at the same time, producing Sunbeam Harrington Alpines and Le Mans conversions for the Rootes competition department. As the company was also main dealer for Rootes cars, cessation of Dove production after around fifty had been produced – it was not as many as 100 as is widely mooted – was somewhat inevitable. The rare Surrey top (left) is worth looking after as they are rare; seals wear.