Triumph TR5 Buyers Guide

A TR5 PI's commission number begins CP, and a TR250's CD; the engine number should agree, CP…E for a TR5 and CC…E for a TR250. Then come the details, and for a car built at Canley a British Motor Museum Heritage Certificate. Converted cars are the trap. TR250s have been given injection, right-hand drive and new badges and sold as TR5s, and Motor Sport warned of the stripe as long ago as 1996:

Identification explains the numbers, where they are and what a certificate shows. The TR Register adds two warnings: make sure the plate's number matches the registration document, and remember that every American car was built with left-hand drive, so a right-hand-drive car with an American past has been converted, well or badly.

Look at the frame before anything else. Its boxed members rot from the inside, the VTR's guide says, and show it first as blisters along the seams; the TR Register singles out the rear half, with the six-cylinder cars appearing to suffer more than the TR4A. Two places matter most, and both are under the car: the mountings of the rear suspension's semi-trailing arms, just behind the seats, and the mountings of the differential.

The German guide explains why the differential's mountings tear: the differential hangs from two bridges by four bolts, too weak for the six's torque, and the tearing usually starts at the right front bolt. A clunk from the back, the VTR warns, can be torn mountings or worn universal joints, which sound alike. At the front the German guide asks a buyer to look for kinks in the frame's tips, from accidents and kerbs, cracks at the lower-wishbone brackets, tears at the welded seams of the steering-rack mountings, and damage to the diagonal struts that carry the spring towers. Sagging sills (rocker panels) and doors that stick, the VTR adds, are a warning about the frame as well as the body.

Rust in the body starts in the same places on every car, and the guides list them:

The inner panels should be in the body colour, the TR Register says, not black or underseal, and the German guide notes that glass-fibre panels are not original. Cars that have come back from America need the same care as any other:

The six is strong, the VTR's guide says, and its weak point is the crankshaft's thrust washers: "These are the biggest failure point." The test needs a helper. Push the crankshaft pulley at the front of the engine towards the back, then have the helper press the clutch pedal, and feel whether the pulley moves forward. The guide allows between 0.18 and 0.33 mm (0.007 and 0.013 in) of end float; more than a fingernail's thickness means work soon, and near 3 mm (⅛ in) the washers may already be in the sump.

The German guide adds the rest. Test the compression and the leakage warm, and expect the oil pressure, also warm, to be above 3 bar (40 psi) at 3,000 on the rev counter; cold readings mean little. A rising level in a full, open radiator during the leakage test points to the head gasket, and so can brown foam under the oil filler cap, though short journeys cause that too. The temperature needle should settle in the middle within 5 km, the thermostat opening at 82 °C. For comparison, Motor Sport's new test car of 1968 showed about 4 bar (60 lb per sq in) at any steady speed over about 65 km/h (40 mph).⁠source 1​source 2​source 9

The injection matters on a TR5, but it is one item among several, and the clubs' guides put it there. Motor Sport's advice in 1996 put it in its place, "When purchasing, watch out for rust in the chassis and check the engine running, as the fuel injection system can give trouble", and the checks are these:

A TR5 that now runs on carburettors has been modified, and its commission number says whether it began as a TR5 or a TR250. How the system works, what went wrong in period and how owners cure it are on the TR5 PI page.⁠source 2​source 10​source 4​source 11​source 5

The VTR's guide covers the transmission and the axle. Listen for noise in every gear and feel for slack in the change. The Laycock overdrive should engage and release promptly, the German guide adds, dropping the engine speed by about a fifth. The differential's bearings are ball bearings; a failed one is often cured by a new differential, and a rebuild needs special tools. The rear hubs' bearings cannot be greased: slack found early means a specialist rebuild, found late scrap, and the guide's advice is "Farm out hub rebuilding!" There are six universal joints, sealed for life at the factory, though replacements may have grease nipples.

At the front, the German guide finds that modern rubber bushes for the wishbones perish quickly, and that polyurethane bushes are common. The trunnions in the vertical links run in brass bushes and need liquid grease or gear oil, never hard grease; hardened grease and perished rubber boots mean worn threads. Check the upper ball joints' gaiters, play in the steering rack, and its rubber mountings, which make the steering vague; aluminium and other replacements are sold. On a TR250 the lower wishbones were fixed to the frame by a second stud, a cure, by the VTR's account, for a TR4A failure.⁠source 1​source 2​source 12

The VTR's guide finds no electrical trouble beyond the usual troubles of the period. Originality is harder on a TR250, whose striped hoses and carburettor vacuum valve the VTR finds scarce; no new harness carries the plug for its American hazard flasher. Parts in general are well supplied, and what interchanges with the TR4A, the TR6 and the 2.5 PI saloon (sedan) is on parts and specialists.⁠source 1​source 12​source 2​source 3