Hi there and welcome to the forum!
What to look for when buying a Sprint!
1) RUST! anywhere and everywhere but particularly (but in no special order) front valance/nosecone, front wings, inner outer and centre sills, door bottoms, front and rear screen frames, rear of roof, "c" pillars, boot floor, rear wheel arches, front floor pans, front chassis rails where the subframe mountings go through, headlamp support panels and the bulkhead area where the flitches meet the heater duct.
Most of these problems are fixable but some, like the front wings and front panel are expensive/hard to get in steel and others like the screen frames, rear roof and bulkhead are tricky to repair and there are no cheat repair section available. The club supply to members a pretty comprehensive range of steel repair sections and GRP front wings and front panels which fit well and look good (I've used them and can vouch for this) Other body bits are available from Triumph specialists.
2) Mechanical, look for noisy engines, top end noise is common on Sprints but is not a good sign. Timing chain noise is bad news, inlet cam bucket sleeves can go oval and valve clearances go out. Water leaks are a perrenial problem and came in several flavours, also check for overheating, this can also have several causes but almost always leads to head gasket failure if not caught early. The clutch release mechanism can give trouble though the rest of the drivetrain is pretty robust as is the suspension. Sprint standard brakes are marginal at best but good upgrades are available.
3) Trim, Vinyl roofs are available but not cheap, likewise headliners. Expect the wooden dash and doorcappings to be a bit tired, new ones do turn up occaisionally but hard work will fix most and good used stuff or restored bits can be had. Seat diaphragms are weak and new ones are NLA but there are get arounds.The seat facing material tends to split in old age, a good trimmer will be able to produce a fair match in most colours but some, particularly blue and the rare grey are hard to get. Good used seats in the more common colours are fairly easy to source. The top of the rear seat is particularly prone to sun damage so look at this. Doorcards and (good quality) carpets are available but very pricey.
This is not intended to put you off and I daresay you could compile a similar list for almost any 70s British car. But be aware that you ARE looking at a 70s British car and use a suitably jaundiced eye! There are some rough ones out there but there are also some very nice ones and even more that are somewhere in between. Choose carefully and you will get a car that gives you a silly grin every time you fire it up and probably a lifelong love affair!
Cheers and good hunting! Steve
2 door '73 Toledo with Vauxhall Carlton engine OWF 797M (The Carledo)
Vermillion (and Rust) Sprint Auto EGP 247T (The Dolomega)
'91 Cavalier 2ltr 8v auto
'95 Cavalier 2ltr 16v auto
Spectrum Auto Services, Servicing, Repairs, MOT prep. Apprentice served Triumph Specialist for 40 years and home of Maverick Triumph.PM for more info or quotes.