Engine
The TR4/TR4A’s 2138cc four-cylinder powerplant is simple, strong and reliable. Derived from the post-war Standard Vanguard unit, it’ll cover 100,000 miles before needing significant attention, although oil leaks from the timing chain cover are an expected part of Triumph ownership. The scroll seal fitted at the rear of the crankshaft also lets oil out; this is only a problem when the engine is running but the vehicle itself isn’t moving. Once the engine is up to running temperature you should be seeing 70psi on the gauge.

The TR5 and TR6’s smooth 2.5-litre straight-six offers huge reserves of torque. With regular oil changes and proper servicing the units will take 120,000 miles quite happily – some owners have seen more than twice this before major surgery is required.

Check for play in the crankshaft thrust washers by pushing and pulling on the bottom pulley. The job is made easier by depressing and releasing the clutch – there should be no more than 0.008in movement. It may also be possible to feel and hear a clonk as the crank moves. Any detectable movement means the thrust washers may have dropped out, which could be serious and may involve the sourcing of a replacement block or even engine. If the thrust washers are still in place it’s possible to replace them with oversized ones, without having to remove the engine first.

See if the original canister type of oil filter has been replaced with a spin-on version – they cost less than £40 so if there isn’t one there you’ll get an idea of how well kept the car is. The original filters had no anti-drain valve, leading to the bearings being starved of oil on start up, whereas the spin-on type keeps the system primed allowing the oil to circulate much more quickly. Once up to temperature check the oil pressure; it should be showing 50-60psi on the dial at 2,500rpm.

The engine is also famed for oil leaks, and rattles at start up. Thankfully these characteristics can be engineered out without too much difficulty or expense. All parts are readily available, and it’s an easy engine to cut your teeth on if you’re buying a project.

It won’t be hard to spot if the engine has worn out. Blue smoke when the car is accelerated points to bore and/or piston wear, while blue smoke when the engine is started indicates worn valve guides – and the requirement for a cylinder overhaul. Rebuilt unleaded heads are available for around £300 to fit yourself or from £500 to have someone do it for you. If you can see black smoke as the car is accelerated quickly, it’s because the fuel-injection metering has been set up to run rich. Not only will this mean steep fuel bills but it will also make for premature bore wear if it’s been that way for a while.

Other well known fuel injection problems revolve around difficult starting from hot, fuel vaporisation and misfiring on start up. These are well known problems and easily remedied by one of the many specialists, or the job can be done at home without any special tools. All parts for the injection system are readily available either on an exchange basis or even outright on a number of components. A common conversion on the fuel-injection system is the replacement of the Lucas pump with a Bosch item, which solves most of the problems of overheating for which the Lucas pump has achieved a reputation.

Replacement powerplants are readily available through the basic engine being common to the 2.5 saloons. Running second-hand engines can be bought from £50, although you’ll have to spend at least £200 to get one that won’t need rebuilding before long. However, for the purist who doesn’t want a saloon engine with an MG prefix, genuine second-hand TR6 engines start at £250.

Transmission
The four-speed gearbox rarely gives problems, as it’s just as tough as the engines. But once 100,000 miles have been racked up the bearings will begin to grumble and it’ll start to jump out of gear. Another common casualty is the layshaft bearings; when cruising you’ll hear a rumbling in all of the intermediate gears, which disappears when top gear is engaged. It can also be identified when the car is stationary with the engine running, by a rumbling noise which disappears when the clutch pedal is pressed down. The only option is a rebuilt gearbox, for which you can expect to pay £350 plus your old one. Overdrive was fitted as an option to give a seven-speed ‘box which gives few problems except for the classic electrical ones in which either the solenoid or the wiring loom play up.

If the clutch isn’t set up properly on any of the cars there’ll be problems. Make sure the clevis pin which connects the clutch pedal to the master cylinder isn’t excessively worn and that the slave cylinder is mounted with the bleed nipple facing upwards – the cylinder can be fitted upside down very easily. This will allow the hydraulics to be bled properly, as if they’re not, the baulk rings in the gearbox will take a battering through the clutch not giving the necessary clearance.

With around 145lb ft of torque available, the transmission will have taken quite a beating if the car has been driven hard. Accordingly, universal joints on the propshaft and half-shafts may be worn; listen for clonks as drive is taken up when the car is driven off. Also get underneath the car and look at the differential’s mounting points, which can be distorted or even torn away by repeated fierce acceleration. Because of the torque levels, the clutch may have seen better days. Make sure it engages smoothly and disengages well before the pedal reaches the end of its travel.

Overdrive wasn’t fitted as standard until 1974, and it’s worth buying a car with it. If fitted but faulty, it’s probably wiring problems, which are easily fixed. Look out for things like broken wires, dodgy relays or loose Lucar connections. It could be because the overdrive unit has clogged up inside or because the solenoid has packed up. CP, CC and CR series TR6 up to commission number CR641 had an A-type overdrive unit fitted. The CF and CR series cars (from CR567) were fitted with a J-type unit. Overdrive solenoids are available from £80, but if the unit just needs cleaning out it will take only a morning of your time.

Check for wear in the propshaft and driveshaft universal joints by using a wrench to turn the shafts while the brakes are on. Any play will be instantly noticeable and if the propshaft is worn out you’ll have to pay around £150 to replace it. Also check for wear in the driveshaft splines which cost around £165 each side to fix – if you’re having to replace these it’s worth investing in a fresh, stronger set from Neil Revington, which are better made and longer lasting. Propshafts need to be greased every 3000 miles if they’re not to seize and they can also go out of balance when the universal joints are replaced, so make sure they’re reassembled in the correct way.

Suspension, steering and brakes
Neither the front nor the rear suspension have any inherent problems, although the rear of the TR4A can be improved by fitting telescopic shock absorbers. Uprated springs are available for the TR4, and these should be fitted without the aluminium spacer that normally lives between the top of the spring and the top spring mounting. But many DIY owners don’t read the instructions and end up fitting the whole lot, which raises the ride height and upsets the handling. You should be able to get just two fingers between the top of the tyre and the rear wheelarch – any more and it’s sitting too high, probably because it’s riding on the wrong springs.

The front trunnions have a habit of seizing because they haven’t been lubricated properly when fitted. This strains other parts of the suspension – especially the drop link on the wishbone – so check their condition by jacking up the car from underneath the wishbone and making sure the trunnions are swivelling properly. Wheelbearings aren’t renowned for their strength; play can be adjusted out, but count on having to replace them if you notice any play.

If wire wheels have been fitted, you need to check for loose or rusty spokes as well as rim corrosion. The splines that hold the wire wheel hubs in place can also wear, so jack up each corner and check for play by trying to rock then spin the wheel while the footbrake is applied. Any obvious movement between the wheel and the hub means the splines have worn. A replacement set costs around £250 including the spinners. Conversion between wires and steel wheels is easy on these cars because the same hubs are used for either model and conversion requires only shortened wheel studs to go along with the set of wire wheel spline adaptors.

Brakes have no inherent problems, but if there is a fault of any sort it’ll be easy and cheap to fix. The brakes have an in-line servo as standard and unless the car has been uprated the stoppers are more than adequate for the purpose. However, the handbrake is poor even with everything in good condition.
Servo assistance was an option on the TR4 and TR4A, but standard on the TR5 and TR6, so don’t always expect to see one fitted to earlier cars. Whether or not there’s one fitted, the brakes should be up to the job, but the handbrake is notoriously poor at holding the car on a hill.

Bodywork, electrics and trim
These cars have a separate chassis, which can rot in all sorts of places and can only really be repaired properly if the bodyshell is removed first. But the construction of the TR4A, TR5 and TR6 mean many chassis repairs can be undertaken with the body in situ. The worst-affected areas are usually the diff mounting brackets (which can snap off), so pay close attention to what state the offside front and nearside rear units are in, as these are most affected by the torque going through the diff.

The centre section of the chassis also needs careful analysis because it bulges as it gets weaker. TR4s survive the best because the chassis is less complex – the TR4A-TR6 have internal strengthening where the rear suspension is bolted to the chassis, and this is an area that corrodes quite readily. Also, because of the very different shape that the later cars have from the TR4, these suffer from flexing that can crack the chassis. These later cars also have differential mounting brackets that are more prone to problem than those on the earlier TR4. The TR5 and TR6 is the worst affected of them all, because the amount of torque put through the diff can cause the mountings to break off altogether.

Poorly repaired accident damage is another probability. The chassis isn’t especially hardy, so even small parking nudges can end up causing distortion. The areas most commonly afflicted are the front suspension turrets, the mounting brackets (the points from which the wishbones pivot), outriggers, steering rack mountings and the suspension itself. Look for distorted metal (particularly kinks where the chassis gets wider on either side of the sump), cracks, naff plating and uneven tyre wear which all give the game away.

Despite the use of a separate chassis, the bodyshell does give some structural strength, especially on the TR4A-TR6 which have a more flexible chassis. Because of this it’s especially important to make sure the main shell is sound and that the doors, wings, sills and floorpans are in reasonable condition. Make sure the drain holes, which should be obvious on the underside of the sill, are all present and correct – if they’re blocked up then the sills will probably be rotting through from the inside. The tops and bottoms of both the doors and wings can rot away, and where the front wings are concerned you have to inspect the inner as well as the outer wing very carefully. The battery sits behind the engine and the metal beneath it rots readily, so if it doesn’t look too great remove the battery and inspect more closely – you’ll probably be glad you did.

Also check the door gaps as they can open up at the top if the chassis has been weakened by corrosion, or if the car hasn’t been properly braced when the sills have been replaced. B-posts and door tops can also succumb to the dreaded tin worm as can the lip of the boot lid so ignore these and you might just regret it. But if the panel gaps are excessive or hideously uneven it could be because the car has been restored very badly. They weren’t put together especially well on the production line, but most will have been restored by now. If a car has been badly rebuilt it’ll be a lot more hassle putting that right than starting with an unrestored example.

Another sign of a bodged rebuild is missing beading along the seam between the top of the rear wings and the deck. The rear wings bolt on and filler is often used along the tops of them while the beading is left out. Speaking of bodges, make sure the footwells are in good shape, as a common bit of sharp practice is to weld replacement panels over already rusty ones – it might look OK but the corrosion will still be there and the car may well be weakened structurally as a result.

Incidentally, because TR5s are worth more than TR4As, it’s not unknown for a six-pot engine to be dropped into a TR4A and passed off as a TR5 – it has to be a TR4A (and not a TR4) because of the independent rear suspension. A TR5 chassis number will start CP, while CT means it’s a TR4, CTC is a TR4A and if it’s a TR250 it’ll start with CD. All these cars have a commission plate, which is located on the nearside front inner wheelarch – always worth a look.

Unless the interior resembles a scene from The Young Ones, a bit of scruffiness inside the car isn’t anything to worry about because everything is available. The Surrey hard tops were always an option, and are now sought after – if the car you’re looking at doesn’t have one but you’d like one, expect to pay at least £400 for a decent example.

The electrics are straightforward; if there are any problems, everything can be fixed easily and cheaply. Replacement parts are cheap and apart from connections not connecting properly there’s little to worry about. A new wiring loom is available for about £200 and it’s not that tricky to fit – a specialist will charge £400-£500 to replace it for you. The only exception to this is if the windscreen wipers are playing up. If it’s the motor that needs TLC there’s very little to worry about, but if it’s the rack that’s unhappy you’ll have to remove the dash to get to it.

If the heater unit seems to be completely ineffective it’s probably because the air vent at the base of the windscreen isn’t open. Just raising the flap by a few degrees makes all the difference between a misted up windscreen and a clear one.

Conclusion
The Americans knew they were onto a good thing, which is why most of these were exported to the US. Now they’re coming back here, and being converted to right-hand drive in the process. Such a job is quite involved but no problem if the car is being properly restored. Also, don’t assume that if you’re buying a car from the US that it’ll be rust-free; they’re often very corroded.

There’s plenty of scope to buy something that will swallow all the money you throw at it, but if you take your time and look at plenty of cars, you’ll see there are some superb examples to choose from.
Buy a good example of any TR, look after it and drive it sympathetically, and you’ll be able to sell it on without losing your shirt on it. If on the other hand you’re looking at buying a car to treat as a project there are plenty of earlier cars on offer (TR5 projects are rarer) along with a decent supply of parts that means you won’t grind to a halt because you’re missing a crucial component.

Whichever route you choose, get ready to listen to everybody you ever meet while out in your TR, because they’ll all want to relate at least one anecdote to you about their friends, relatives or neighbours who ‘used to have one of those’.