Triumph TR5: the rare fuel-injected six (1967–1968)

The Triumph TR5 is the one the enthusiasts chase. It was built for barely thirteen months, only 2,947 were made, and it was the first of the TRs to carry a six-cylinder engine. To look at it is almost a TR4; to drive it is something else entirely, because under that familiar body sits a fuel-injected 2.5-litre straight-six making 150 bhp.

That combination of rarity, speed and the familiar Michelotti shape has made the TR5 one of the most valuable and sought-after of all the Triumph sports cars, the quiet, fast bridge between the four-cylinder side-screen era and the muscular TR6 that followed.

The first six-cylinder TR

The TR5 arrived in 1967 to solve a simple problem: the four-cylinder TR4A was running out of performance against newer rivals. Rather than design a new car, Triumph dropped a 2.5-litre straight-six into the existing body and added Lucas mechanical fuel injection, the system badged PI.

The result was a genuine step up. The injected six made 150 bhp, enough for a top speed around 120 mph and a 0 to 60 time of roughly eight seconds, quick for a 1967 sports car and a world away from the side-screen TRs. The car kept the independent rear suspension introduced on the TR4A, so it handled as well as it went. The only outward giveaways were the discreet PI badging and the new bonnet, because Triumph had spent its money on the engineering, not the styling.

TR5 PI versus the American TR250

The single most important thing to understand about the car is the split between home-market and American versions.

UK and European cars were the injected TR5 PI, with 150 bhp. American cars were a different animal: badged TR250, fitted with twin Zenith-Stromberg carburettors to meet US emissions rules, and making only around 104 bhp. The TR250 also wore the distinctive transverse “go-faster” stripes across the nose. Crucially, the numbers were lopsided: just 2,947 injected TR5s against 8,484 carburettor TR250s.

For a buyer the consequences are large. The TR5 PI is rare, powerful and the more valuable by a wide margin, while the TR250 is more common, softer and far more affordable. The badge on the tail, and the presence or absence of the injection system, tell you which you are looking at and roughly what it is worth.

What it is like to drive

The TR5 is a wolf in TR4 clothing. The straight-six is smooth and torquey, pulling hard from low revs, and on a properly sorted injection car the performance is still genuinely brisk today. It feels notably quicker and more grown-up than the four-cylinder cars, yet it keeps the compact size and the direct, mechanical feel of the side-screen TRs. With the independent rear suspension it rides and corners better than the early cars, and it makes a relaxed, fast long-distance roadster.

Buying guide: what to look for

The TR5 shares its structure with the TR4A, so the chassis is the first thing to inspect, particularly the rails towards the rear and the suspension and differential mounts, because a rotten chassis means a body-off rebuild. The usual body rot traps apply: sills, floors, lower wings and the boot area.

The defining mechanical issue is the Lucas fuel injection. It has a reputation for being temperamental, which is largely a question of correct set-up and a healthy metering unit and pump rather than a fundamental flaw; many cars now run uprated pumps. Because the TR5 is rare and valuable, provenance matters more than on any other TR: check the commission number, the documentation and that the car is a genuine injected TR5 rather than a converted TR250 or a rebodied four-cylinder car. Parts supply is excellent thanks to the shared TR6 mechanicals.

Why it is so collectable

The TR5’s value rests on three things: it is rare, with under 3,000 built; it is fast, as the first and arguably purest of the injected sixes; and it is significant, as the car that introduced the engine and running gear that would define the best-selling TR6. A good TR5 PI is now firmly into five-figure territory and the best cars beyond, making it one of the most valuable TRs. The TR250, by contrast, remains an affordable way into six-cylinder TR ownership for anyone less concerned about the injection system.

Owners’ clubs and parts

The TR Register and the TR Drivers’ Club both have strong followings for the six-cylinder cars and real depth of knowledge on the Lucas injection, which is exactly the expertise a TR5 owner wants. Mechanical parts supply is excellent because the engine and running gear are shared with the far more numerous TR6.

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