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Triumph TR4/TR4A

Published: 28th Jun 2011 - 0 Comments - Be the first, contribute now!

Triumph TR4/TR4A
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Overhead valve, in-line four-cylinder 2138cc, 100bhp (TR4A, 104 bhp)

Sundry items

Every 3000 miles, or annually (whichever comes first)... Check clutch and brake fluid levels. Examine the steering rack gaiters for splits/leaks. If damaged, the gaiters need to be replaced at once, to prevent the ingress of dirt and moisture to the rack. Check/re-lubricate front wheel bearings. Check all electrical connections; inspect all wiring for damage. Assess the condition/security of all running gear components, steering rack mounts/attachments/gaiters, and suspension mounting bushes, also the ball joint gaiters. Ensure that all suspension mounting bolts/nuts are all tight. Check the shock absorbers for deterioration/leaks. Examine propeller shaft couplings. Inspect the underbody for damage and rectify paint blemishes.

Fuel system

Every 3000 miles/annually, examine all fuel system pipework and check/top up the carburettor dashpots with light machine oil. For further details check workshop manual specific to your version (TR4s and early TR4As were fitted with twin Stromberg 175CD carburettors; later TR4As were equipped with twin SU HS6s). With the engine fully warmed up, check/re-set the carburettor balance/mixture settings (use proprietary equipment for precisely balancing the carburettors); consult your workshop manual for full details. Clean gauze type air filters in fresh paraffin (dry, then lightly re-oil using engine oil before re-fitting), or renew paper type air filter elements, in each case every 12,000 miles (or sooner if visibly dirty; check every 6000 miles). At each service, ensure that the breather pipework is clean. Every 12,000 miles, clean the fuel pump’s filter.

Cooling system

All year round, use top quality anti-freeze mixture containing corrosion inhibitors. Consult specific product instructions for mixture strength. Ideally use distilled or de-ionised water in the cooling system, rather than ordinary tap water. Every 3000 miles/annually, inspect the radiator, all hoses and their securing clips, the fan and the water pump. At least once a year examine/carefully clean with a soft brush the exterior of the radiator. At least every three years, drain the system, remove the thermostat and reverse-flush prior to re-filling the system with fresh anti-freeze solution. At each service, check that the fan belt is in good condition and correctly tensioned – that’s approx. 3/4in. (19mm.) deflection under firm hand pressure, applied mid-way in longest belt run. Cooling system capacity, including heater: Approx. 11 pints (6.25 litres).


At least every 3000 miles or annually, whichever comes first, check the fixed brake pipes, flexible hoses, master cylinder and servo/pipework. Renew any ailing components AT ONCE. In addition, closely scrutinise the front brake pads and discs (look for scoring and/or warping). Closely inspect the rear shoes, cylinders and drums (remove the drums for a full inspection). AVOID INHALING DUST FROM THE PADS/SHOES IT MAY CONTAIN ASBESTOS. USE A PURPOSE-DESIGNED BRAKE CLEANER FLUID TO DAMP IT DOWN
Check handbrake operation and re-adjust the mechanism if handbrake lever travel is excessive after having adjusted the shoe to drum clearance at the rear brake backplates (consult your workshop manual for full details specific to your model). On the TR4 the cable adjustment is carried out adjacent to the handbrake lever; on the TR4A the adjustment is effected at the rear axle. In all cases, after adjustment, ensure that brakes are not binding with the handbrake lever in the off position. At least every 18 months/18,000 miles (whichever comes first), change the brake fluid.


Spark plugs: NGK BP6HS or equivalent. Gap 0.025in. (0.635mm.). Check/clean every 6000 miles or annually (whichever comes first); renew regardless every 12,000 miles. Apply a little copper-based anti-seize compound to plug threads on installation; this will help to prevent seizure of the plugs within the cylinder head. Firing order: 1-3-4-2 (No. 1 cylinder at front of car). Contact points: Gap 0.014 to 0.016in. (0.36 to 0.41mm.) corresponding with dwell angle reading of 13 degrees. Check/clean contact breaker points every 3000 miles or annually (whichever comes first); renew regardless of state every 6000 miles. Distributor cap, rotor arm and high tension leads: Every 3000 miles/annually, clean and check condition, ensuring that all connections are properly made. Distributor: mechanical aspects: Every 3000 miles/annually, remove the rotor arm and apply a few drops of engine oil to the rotor shaft, also to the distributor shaft/cam bearing and mechanical advance mechanism (via apertures in the distributor baseplate). Apply a smear of grease to the distributor’s cam. Timing: Set by reference to the pointer on the timing case (Top Dead Centre or T.D.C.) and a hole in the crankshaft pulley. Static setting: 4 degrees Before Top Dead Centre (BTDC)

Valve clearances

Every 12,000 miles, check the valve clearances, which should be 0.010in. for both inlet and exhaust valves, with the engine cold. Remove the valve cover (always fit a new gasket on re-assembly), then check/adjust the valve clearances using the Rule of Nine. Check the gap on valve No. 1 with valve No. 8 fully open, No. 2 with No. 7 open, No. 3 with No. 6 open, and so on; in each case the sum of the valve numbers is nine. If any of the gaps are found to be incorrect, re-setting is straightforward; a conventional screw and locknut system is employed. Re-check the gaps on completion of any adjustments.


Engine oil: Ideally change the oil and filter at least every 3000 miles or annually (whichever comes first). Drain the oil (using an 11/16in AF socket or ring spanner on the sump plug) after a long run, to aid lubricant flow from the sump. Remove the oil filter housing plus filter element, and clean the casing plus associated components in fresh paraffin; wipe dry before re-assembling with a new filter element. Note: Modern spin-on/spin-off filter conversions are readily available from TR specialists. Use good quality, full bodied multigrade oil, for example SAE20W50 or 20W60 and preferably a classic oil. Please dispose of old oil and filter in an environmentally friendly manner – local councils provide waste oil collection points. Refill sump capacity, including filter: Approx. 10 pints (5.68 litres). Every 12,000 miles/annually, clean the engine oil filler cap’s gauze (swill in fresh paraffin or engine degreasing fluid, and fully dry before re-fitting). Gearbox/overdrive oil: At least every 3000 miles/annually (whichever comes first), check/top up the gearbox/overdrive oil level (with the car horizontal); the oil should be up to the base of the threads in the filler aperture. Top up if necessary with SAE 90EP hypoid oil. Every 24,000 miles/two years (approximately), drain the gearbox (and overdrive, where fitted). Tackle this job after a long run, when the oil has fully warmed up. When the old oil has completely drained, wipe clean the drain plug(s) and aperture(s), re-fit the plug(s) and re-fill with fresh oil. Gearbox/overdrive, total refill capacity: Approx. 2.75 pints (1.56 litres). Rear axle oil: Approximately every 3000 miles/annually (whichever comes first), remove the filler/level plug and ensure that the oil is up to the base of the threads in the plug aperture. Top up with SAE 90EP hypoid oil: dry capacity approx. 1.5 pints (0.85 litres). Note that no drain plug is fitted to the axle. At each service ensure that the axle breather is unobstructed. Check at each service that all handbrake operating mechanism pivot points move freely and are properly lubricated. Other aspects: Every 3000 miles/annually, lubricate the carburettor pivot points/controls, and accelerator pedal pivot. Every 3000 miles/annually, lubricate the hinges and lock mechanisms (wipe off excess lubricant). Every 3000 miles/annually, re-lubricate the dynamo rear bearing (with a few drops of engine oil). Every 1000 miles, re-lubricate all lubrication points (consult Triumph literature for full details). TR4: 22 lubrication points; TR4A; 24 lubrication points. Note that some owners/specialists recommend lubricating the front and rear trunnions with EP90 oil, rather than grease. The important aspect is to ensure that lubrication is carried out regularly. Note: Some (original type) water pumps are fitted with a grease nipple, and regular re-greasing should be carried out. On some later pumps, a little water pump grease can be introduced via the small access aperture in the body of the unit.

Best Mods

  • Even if you want to keep the car standard, TR experts reckon the 4 was somewhat under cooled even when new, and using unleaded fuel makes them run hotter still. Fitting a bigger, modified radiator is a popular and worthy mod – try Radtec.
  • That big lusty engine can be taken out to 2.2-litres if it needs reboring (which being a sleeved unit is easy – and with usual head, cam and breathing mods (of which there are plenty of tuning parts available from specialists) can kick out a useable 130bhp on the road that’s enough see off many a TR6!
  • The TR4’s handling is inherently superior to the later big sixes due to a less heavy lump up front; just the usual spring/damper upgrades will suffice for road use along with harder bushing although this will make the ride harsher, especially on the early 4 which doesn’t have the IRS fitted.
  • Incidentally, the disc brakes on pre-1964 TRs were better than later cars – even the six pots – as they were bigger! This means that so long as they are in proper order, the normal set up (with uprated pads of course) is suffice to handle up to 150bhp although you can go more extreme with larger vented types if you so wish.

Top Tips

  • Mechanically the TR4 and 4A are as tough as a pair of regulation army boots. The engine’s wet liner design means the bores can be re-sleeved ad infinitum, which means almost open ended engine life provided these power units haven’t been horribly abused. Look for a 70lb oil pressure and watch for oil leaks.
  • Although straightforward, gearboxes can get tired with layshaft problems. The 4A had a diaphragm clutch, which is more failure prone, so judder, slip and thrust bearing noise may occur.
  • If you need a new clutch soon then bear in mind that the original 4A clutch was a Laycock unit, which is apparently becoming scarce. Many owners fit aftermarket Borg and Beck units, but these aren’t quite as longlasting.
  • In the 4A a lot clutch backlash could mean worn drive shaft splines although equally these could relate to worn universal joints.
  • As you come to expect from a classic Triumph the front suspension trunnions are a weak point as they can seize up if they are starved of servicing – they really can’t be lubed too often if you want to protect them.
  • Chassis rot like any other old classic. Check the trailing arm locating areas on 4As, as these are particular rust traps. Body locating chassis outriggers – a common rot point, and often badly repaired- and the chassis arms located under the boot floor can give trouble on both the 4s and 4As.

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