Sprite & Midget make great track cars without going broke

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Sprite & Midget make great track cars without going broke

‘The beauty of the Midget,’ says arch A-series exponent Rae Davis, ‘is that there is so much you can do with them, whether it’s a modsports-type car or a hillclimber.’ A complete raceable car for the MGCC Midget Challenge – with three classes to choose from, or MGOC Class A for basically standard cars – could be had from £4000 up, though an FIA-spec car is nearer £25k – and you can spend more than that building one.

Engine
The technology here is the same as for Mini racers – though the rules are generally looser than for Appendix K cars, with MGCC rules allowing 1380cc, which ‘99% of 1275 blocks will go straight out to, although you must offset the bores,’ says Rae Davis. ‘Cooper S conrods, although they’re heavy, don’t break, and the cranks are pretty good too. You could build a decent engine using standard parts for £4000, although the sky is the limit.’

A proper big-valve unleaded exchange head is around £600; a complete roller-rocker 1380cc race engine £3180 outright from Peter May. Check your chosen series rules carefully, as some classes allow roller rockers and free carbs and manifolds.

Transmission
Straight-cut close-ratio gearsets with a new first gear are £560 from Rae Davis Racing; a full-house Quaife dog box is around £2500. ‘Midgets tend to unload their inside rear wheels in corners, so if you’re using an LSD it needs to be a plate type,’ says Davis. Halfshafts are a known weakness but RDR offers a two-piece replacement for £140 a side, ‘which stops the hub wandering about’.

Suspension
‘The general rule is stiff on springs, anti-roll bar and dampers at the front, soft on the rear springs but firm on the damping,’ says Davis. Front anti-roll bars are available in four diameters from 5/8in to 7/8in. The next job is to get some negative camber on the front; RDR makes a special top trunnion that stops the outside wheel going into positive camber in corners, without needing excessive negative in a straight line ‘when you’re only using three-quarters of the tyre width and you can’t stop them’. RDR uses longer-lasting Nylatron spring pan bushes, but the wishbone/spring pan needs local welding reinforcement. Spring rates are 371lb/in standard, while racers use anything up to 600lb/in, available from a wide range of sources including Moss Europe.

Dampers are an important factor, and RDR has developed an adjustable valve that screws straight in. Some race categories allow telescopic dampers, available from Frontline. Pre-1973 cars used beefier steering racks that have a faster ratio than later ones – but you need the corresponding mounting brackets and steering arms too, as they take bigger balljoints. Midget steering should be light, so if it’s stiff, off-kilter mounts might be straining the rack housing slightly, needing careful shimming to eliminate. Recon early-type racks cost around £80.

Wheels and tyres
Standard 13in maximum diameter and no point going too wide says Davis, as too much grip just pulls the centres out of the tin wheels (so they’re prohibited in MGCC racing). A 5in Minilite type is best, with some classes allowing wider, and MGCC specifying KN alloys. The MGCC roadgoing class and MGOC Class A use 175/60x13 Yokohamas as a control tyre. Dunlop Racing tyres are mandatory for Appendix K (Heritage GTS, Lenham GT Challenge).

Brakes
You’re usually stuck with the original tiny discs front, drums rear, when there’s not much you can do apart from change to decent friction material. Both Frontline and Peter May produce a 9in or 10in disc conversion, which may be allowable in some series, and there is the option of Metro four-pot calipers too. ‘Circuit cars don’t want much back brake,’ says Rae Davis.

Body and interior
MGOC rules allow seam-welding. Bolt-in roll hoops cost from £250, though as Davis says: ‘If you possibly can, get a cage fitted by a specialist. It not only looks so much better, I know which I’d rather be sitting in if I did roll it.’

Minimum weights vary from 510 to 705kg depending on age and class. Finally, don’t forget the old racer’s dodge of reversing the steering wheel to give more elbow room and a straighter-arms stance – there’s not much room in either a Sprite or a Midget.