Triumph TR4 Buyers Guide

Assume the car has been restored at least once, the German guide advised in 2009, and that a closer look may show it needs doing again; the condition of the body against the asking price is the deciding question. Between a TR4 and a TR4A, the insurer's guide finds no great difference to weigh apart from the TR4A's independent rear suspension, which gives a better ride, though there are fewer TR4As to choose from. A left-hand-drive TR4A may have the live axle of the cars built for North America, so check which it is before buying: the commission number shows it, and identification explains how.

The German guide suggests taking a screwdriver, a small hammer, a magnet or a paint-thickness gauge, an angled mirror on a handle and a strong torch, and, better still, an experienced club member. Both the German and the American guides advise joining a club first, and the Vintage Triumph Register's sums up the alternative in an old proverb: "Marry in haste – repent at leisure."

The TR4, TR4A, TR5 and TR250 share a body shell that the German guide calls largely identical, differing in their lamps and in the inner wings (fenders), shaped for the four or the six, so many panels interchange. Rust collects where dirt does, and the German guide's list is long:

The Vintage Triumph Register adds the trailing ends of the front wings, where mud collects, and the upper rear arches, and reminds buyers that "The fore/aft strength of the car counts on solid sills". Uneven gaps at the doors' trailing edges point to a sagging sill or frame, or a poor restoration, the insurer's guide notes. Glass-fibre panels are not original; they were fitted when steel ones were scarce. The windscreen (windshield) frame is part of the structure, and the insurer's guide also says it is one of the few pieces of metalwork that cannot be bought new, though supply changes; look for filler in it. Check for leaks too, with the hardtop and without: the hardtop of Motor Sport's test car of 1963 let water in at a window joint.⁠source 2​source 3​source 4​source 1​source 6

The TR4's frame is largely the TR3A's, with a wider front and new mountings for the steering rack. The TR4A's is new, and its rear half is the part to worry about: crossmembers welded between the side members, with reinforcing plates over and under them that rust from the inside, out of sight. The German guide warns that repairing them is laborious and that a reconditioned exchange frame may cost less. The TR Register's guide finds the front half of any TR frame most prone to damage in accidents.

The German guide's checks, from front to back: the front horns of the frame, for kinks and crushing; the brackets of the lower wishbones, which crack and break, especially from the TR4A on, tearing at the seam where they are welded to the steering-rack mounts, and which should be renewed with the cross-bracing that the TR6 had from the factory; the diagonal braces from the spring towers to the frame; the four side members, tapped for rust, though the middle of the frame is rarely damaged; and the rear end, for accident damage and rust where dirt has held water. The insurer's guide adds that the outriggers and rear suspension mounts "can be vulnerable". The Vintage Triumph Register has even come across a TR4 frame carrying TR4A panels.⁠source 3​source 2​source 4​source 1

On a TR4A with independent rear suspension, the differential hangs from two bridges between the rear side members on four studs, which the German guide calls too weak for the engine's torque. They tear out, and the damage can be judged only with the differential removed; a repair should add a reinforcement and a torque stay. The Vintage Triumph Register describes the warning sign:

At the front, the wishbone bushes should have no play; the German guide noted in 2009 that polyurethane bushes were widely fitted and that new rubber ones were often poor. The stub axles turn in brass trunnions, which wear quickly if they are not lubricated, or are greased with something that hardens: the guide advises gear oil, and reads cracked old gaiters as a sign of long neglect. Split gaiters on the upper ball joints let water in. The steering rack develops play, and soft rubber mounts on the frame horns make the steering vague; firmer mounts were sold, the guide added.

The live axle of the TR4 and the American TR4A is robust, though the bushes in its spring eyes and damper links wear, and tired springs sag. The TR4A's independent rear suspension has universal joints that need lubricating, sometimes awkwardly, and wear noisily; the Vintage Triumph Register suggests the TR250's rubber gaiters over the inner joints. Its splined half-shafts could bind under power even when new. Wire wheels wear at their splines, hubs and spokes and should be checked regularly, and weak brakes, the Vintage Triumph Register finds, often mean badly adjusted rear drums.⁠source 4​source 2​source 7​source 8​source 9

The wet-liner four is tough. The German guide expects normal valve-gear noise but no knocks or rattles, and no leaks except perhaps from the rear main seal on an engine without a modern lip seal. It suggests a compression test on a warm engine, with all four cylinders reaching 10 bar, and, more reliable, a leak-down test: air escaping at the oil filler points to the rings, at the carburettor to an inlet valve, at the exhaust to an exhaust valve, and coolant rising in the radiator to the head gasket. Brown foam under the filler cap may mean a failing head gasket, or only a car used for short trips. The Vintage Triumph Register's guide recommends the same tests, with the oil pressure read on a separate gauge and the coolant tested for exhaust gas.

The oil pressure, hot, should be over 3 bar (40 psi) with the engine at 3,000 rev/min, the German guide says; Motor Sport's test car of 1963 showed about 4.8 bar (70 lb/sq in) in normal running. Low pressure may be cured by a new oil pump and big-end shells, the Vintage Triumph Register notes. After about 5 km the temperature gauge should settle in the middle, and the German guide gives the opening temperature of the correct thermostat as 74 °C; overheating may mean a missing radiator shroud. Liners and pistons are made in a range of sizes, and the liners can be changed without reboring the block.⁠source 2​source 5​source 6​source 4​source 10

Every gear should engage without baulking. Listen for bearing noise: a grinding that stops when the clutch is pressed points to the gearbox's bearings, and a noise only with the pedal down to the release bearing. To test the clutch for slip, the German guide suggests trying to pull away in third gear with the handbrake on: a sound clutch stalls the engine. Overdrive should engage at once, dropping the revs by about a fifth; its faults may be electrical or simply low oil, the insurer's guide says, and the Vintage Triumph Register finds its adjustment simple. The insurer's guide thinks the gearboxes "a little more fragile" than the engines. At the differential flange the propshaft should have no more than 8 to 9 mm of free play, and the universal joints should be checked by hand.⁠source 2​source 1​source 4

The instruments should be the originals: overhauling them is possible but costly, the German guide warned, and in 2009 it counted them among the parts no longer being made, with the wheels, the steering and the horn push with its built-in indicator switch, though supply changes. Carpets and trim were being reproduced, and the guide pointed buyers to the originality guides for the correct patterns. Even new, a TR4A could rattle: one owner wrote to Motor Sport in 1967 of scuttle shake and of trim screws that needed tightening.⁠source 2​source 9

Tuning a TR4 was nothing new. In the 1960s the competition department of Standard-Triumph's American company offered tuning parts for the TR4 and TR4A, among them camshafts, an oversize-piston kit, Weber carburettors (promised for the TR4A in 1966), competition springs and anti-roll bars, and its owners' club newsletter announced a new camshaft in 1964. In the same issue a member advertised a Judson supercharger for the TR4. No source read covers six-cylinder or V8 conversions, so a car with one has to be judged on its own.

Copies of the works rally cars are built, and the body parts to make one are sold, so a works look settles nothing: notable TR4s explains how to tell the works cars from their copies.⁠source 16​source 17​source 18​source 19