Triumph Spitfire Buyers Guide

A Spitfire's chassis is a backbone of two box-section steel beams with outriggers that carry the body tub, a modified form of the Herald's. The Herald's frame ran out to either side of its central members; the Spitfire's has only a handful of outriggers, so, as Practical Classics explained, its body depends on strong sills. Hagerty makes the same point from the other side: because the strength was built into the sills, rust there can be bad news.

The chassis checks still matter, chiefly for crash damage. The guide of the Triumph Sports Six Club (TSSC) says that kinks, cracks or distortion in the main members where the suspension is mounted mean crash damage, in which case "the car is best avoided". It calls the rails around the differential "a well known rust-trap" and says the centre section hardly ever rusts badly. The front outriggers, which hold up the bulkhead (firewall), take the water and dirt thrown up by the front wheels. Practical Classics noted that they have a drain hole and can be replaced without lifting the body; the TSSC adds that corrosion of the body where it sits on them is hard to repair properly unless the body comes off. On a Mk IV or 1500, check the short chassis extensions behind the front bumper too, for rust and for accident damage.⁠source 6​source 4​source 1​source 2​source 3

Look at the body with the car on level ground, then with it jacked up, and lift the carpets and the seats: Practical Classics warned that a carpet stuck down may be hiding the floor. Anglian Triumph Services, a Norfolk specialist, told Hagerty where the rot is found:

At the foot of each front vertical link, the upright that carries the stub axle, a brass trunnion joins the link to the lower wishbone; as the wheel is steered, the link screws up and down the trunnion's thread. British Leyland's brochure for the 1974 model year in the United States called them "patented screw-type lower bushings with built-in oil reservoirs". Starved of oil, the thread corrodes, tight spots develop and the vertical link is strained, Practical Classics warned, "to the point of breakage".

The rear suspension has trunnions too, about a third of the way up each rear vertical link. They can partly seize, but the only sure test is to disconnect the link from the spring and pull it in and out, which Practical Classics conceded no buyer would do while viewing a car. In 2021 Hagerty reported that Canley Classics sold a conversion that does away with the front trunnions; no source read says whether it is still made.

Rock the steering to feel for play between the steering wheel and the road wheels, and in the column and the rack. Vibration through the wheel, the TSSC's guide says, usually means worn wheel bearings, a worn rack or wheels out of balance. Bounce each corner of the car: it should rise and settle once.⁠source 1​source 6​source 9​source 2​source 3

The Spitfire 4, Mk II and Mk III have swing axles at the back. Each driveshaft is the lower link, and the transverse leaf spring bolted to the top of the differential is the upper one. Because the spring is longer than the shaft, a rising wheel gains a large positive camber, and the high roll centre lets cornering forces lift, or jack, the back of the car. Canley Classics describes what follows:

The period testers met the same habit, and road tests has what they wrote. The Mk IV and 1500 kept the swing axles and changed the spring to what Canley calls a swing spring: only the bottom leaf is bolted to the differential, and the upper leaves sit in a box on a pivot, so the roll centre can move and the jacking loads fall. Because the back of the car then resisted roll less, a thicker front anti-roll bar was fitted. In 1973 a longer spring and longer driveshafts widened the rear track by about 50 mm (2 in), and Motor Sport found in 1975 that the rear wheels' old habit had gone.

An early car may have been converted. Swing-spring kits for the Spitfire 4 to Mk III copy Triumph's own cure, and Triumph Sportscars, an Australian specialist that closed at the end of 2016, recommended a Mk IV rear spring and front anti-roll bar for early cars. Some owners fit the GT6 Mk II's rear suspension instead, which Triumph Sportscars thought gained little over a well set-up Mk IV or 1500 rear. None of these is original, so ask what has been done. triumphspitfire.com's alignment notes say that rear camber cannot be adjusted, and that camber outside the factory limits generally points to a weak or wrongly set spring, or to worn vertical-link bushes.

The rear wheel bearings were designed to be greased through a nipple, but the cars left the factory with blanking plugs where the nipples should be, Practical Classics found; left dry, the bearings fail, and the shafts follow them. A hub should come off with a proper puller or with heat, not a three-legged puller, and Canley Classics, which warns that a worn needle roller can eat into a shaft until it is scrap, found only the original Churchill tool reliable. On top of the differential a split pin in a hole serves as the breather: if it is blocked, oil is forced out past the flange seals.

On the test drive, noises point to their causes, from the wheel bearings to the propshaft that runs from the gearbox (transmission) to the differential:⁠source 1​source 10​source 3

Every Spitfire engine is an overhead-valve four with three main bearings, developed from the Standard Eight's 803 cc design. On the Spitfire 4 to Mk IV engines, Practical Classics warned, the thrust washers that control the crankshaft's end-float can drop into the sump. Watch the crankshaft pulley while a helper presses the clutch, or push and pull the pulley: caught early, the fix needs no engine removal, but left too long the crankshaft grinds into the rear main bearing cap. The Mk IV and 1500 engines are more prone to crankshaft wear and bearing rattle; the TSSC adds that the 1500's longer stroke was harder on the crankshaft bearings, and Motor Sport found its engine rough at the top of the rev range in 1975.

From cold, a few seconds of rumble before the oil pressure builds is normal, the TSSC's guide says. Listen for the tappets and the timing chain, watch for blue smoke under acceleration, look inside the rocker cover for a mayonnaise-like sludge, and check the head, sump and rocker-cover gaskets for leaks. Spitfires left the factory with an oil-pressure warning light, not a gauge, as Practical Classics and Motor Sport's testers noted. No valve-stem oil seals were fitted at the factory either. Canley Classics says seals can be added to the inlet valves, and that worn piston rings need a rebore.

Cars for Britain had twin SU carburettors; most American cars from the 1970 model year had a single Zenith-Stromberg. The "Waxstat" jets of later 1500s gave poor starting when hot, Practical Classics found, and the cure was the earlier jet with its choke linkage. For cooling, Pearson advised against an electric fan in front of the radiator and suggested a full-width radiator in place of the "slightly undersized" original. The engines run on unleaded petrol (gas): new exhaust valves and seat inserts are needed only if the valve seats start to recede, and the ignition timing need not change, according to Canley Classics and Practical Classics.⁠source 1​source 16​source 13​source 3​source 4​source 12​source 10​source 17​source 7​source 6

The Spitfire 4, Mk II and Mk III have no synchromesh on first gear; the Mk IV gained it. The 1500's single-rail gearbox was shared with the MG Midget 1500 and, in developed form, the Triumph TR7. Practical Classics noted that its internals fit the Mk IV's casing, that the casing fits the drivelines of the earlier cars, and that the gearboxes got better as the model evolved. The oil level matters, because the box holds little.

On the test drive every gear should engage cleanly and stay in, and the overdrive, if fitted, should engage and drop out cleanly in third and top. Overdrive was a Laycock D-type until a J-type replaced it at commission number FH60000, late in the Mk IV's run; John Kipping, writing for Canley Classics, tells them apart by the solenoid, on the right of a D-type and on the left of a J-type. A D-type's faults are often electrical, in the relay or the solenoid's contacts, and black, hairy particles in its filter mean its clutch lining is breaking up. On a J-type the solenoid causes most trouble, and the late units have a flaw of their own:

Kipping advised changing the overdrive's oil at least every 80,000 km (50,000 miles), without additives. The clutch is hydraulic, and the TSSC's test is to try to make it slip at 80 km/h.

Every Spitfire has disc brakes at the front and drums at the back. According to Triumph Sportscars, Girling 12P calipers were fitted to the Spitfire 4 and Mk II and 14LF calipers from the Mk III on, and a dual-circuit system came with the Mk III for American cars and about 10 years later for British ones; the 1978 British brochure lists dual circuits. Motor Sport noted in 1975 that the 1500 had no servo as standard.⁠source 1​source 11​source 12​source 8​source 10​source 3​source 15​source 17​source 13

Start with the numbers. The commission plate on the left of the bulkhead should match the car's papers, and the engine number's prefix should fit the car: FP is an MG Midget 1500 engine, and KC or KE a GT6 six. Identification explains the numbers and what a Heritage Certificate adds, and how American model years and titles work is on North American Spitfires.

Then look for what has been changed. Danny Hopkins surveyed Spitfires with other engines for Practical Classics in 2003, from the fitting of a 1500 engine to an earlier car to a Rover V8. Of the six-cylinder cars he wrote:

The radiators Hopkins found on converted cars came from Volkswagen, Saab and Renault. Hagerty adds sports seats, Minilite-style alloy wheels and performance exhausts to the common changes.⁠source 1​source 5​source 8​source 18​source 19​source 20​source 21​source 10​source 17​source 6​source 2

A Spitfire is simple to work on, with its body on a separate chassis, and most of its panels are made again: parts and specialists sets out what is made and what is hard to find. Replacement sills do not all fit alike, Hagerty's specialist said. The original hoods (soft tops) were vinyl, and mohair is a popular replacement, Hagerty says; check that it fits. The restoration manuals and buyer's guides in print are listed on the sources page.

In an advertisement, "restored" can mean only refurbished, and the Dutch Triumph Spitfire Club warns buyers that new sills painted over a rotten car are not a restoration.⁠source 3​source 1​source 2​source 8