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Sensible tuning turns the MGA into a very capable and enjoyable sports car, as we reveal
The car that bridged the gap between old school MGs and the swinging 60s, is it any wonder that so many regard the MGA as Abingdon’s best sports car? When compared to the hairy-chested Healeys and tough TRs that were its contemporaries, the MGA maybe seen as just a little bit too pretty and pert to be a true performer – but history over 60 years show those ‘experts’ were wrong and today an MGA can be turned into a cute yet contemporary performing classic.
Before you start
The MGA shares a lot of its underpinnings with the TF1500 which preceded it – the chassis is a development of the T-Series item, brakes were drums all round, and the 1489cc B-Series engine in early cars was to the same specification as in the aging TF.
This commonality and simplicity, makes running an MGA a sound proposition however. In particular, the BMC B-series engine is an ideal candidate for performance mods given the number of MG and MGB specialists out there, and there’s good interchangeability of parts.
The B-Series is a well-known and wellsupported engine – no nasties lurk apart from weak cranks on early 1500 units; a later 1622 fits but needs machining work, unlike the 1558cc Twin Cam cranks but these are extremely expensive, as you’d expect. Check that the oil pressure reads between 50psi and 60psi at 3000rpm; blue smoke indicates worn piston rings or cylinder bores. Cylinder heads have been known to crack, with the first outward sign being a blown head gasket, so it’s important to ascertain if your engine is fit enough to tune.
Bodies and chassis rot big time so keep a regular check on things. Front and rear chassis legs should be kept an eye on although floorboard supports are the first bit of the chassis to corrode along with the wooden floorboards! Wings and sills are often crusty – costly to replace and hard to line up, but repairs can be effected to the original panels if need be but restoring an A to a capital state isn’t exactly cheap.
As it’s a B-Series, like the MGB, but smaller and sweeter a lot of the tuning practices applied to a B can be adapted, and this includes fitting the 1798cc lump but specialists advise using the early three bearing MGB unit, as it looks like an MGA unit and retains the mechanical speedo drive. The stronger but not quite so freerevving five-bearing units are slightly larger and require more work to install, but chrome bumper models at least have the engine mountings in the same place. Against this we’re told that the late rubber bumper units are the toughest of the lot.
Going the MGB route nets you an extra and reliable 20 or 30bhp straightaway – the same as you’d get from cylinder head mods, a hairy cam to a standard MGA engine, but for far less cost. Also the 1798cc engine can be taken out to 2-litres fairly easily.
There are also more tuning parts available for the MGB spec engine – better aftermarket pistons, for example – and the MGB spec engines benefits from stronger crankshafts, says leading but now retired MG expert Bob West.
So, unless you have strict capacity limits for FIA racing or rallying, an MGB engine is the wisest modification. MGA engines need a stronger crank, better quality pistons, a hot cam like a Piper 285 plus you’d need to do a lot of work on the cylinder head to achieve standard MGB poke – to get 95-100bhp out of an original 1500 would cost far more and take far longer to achieve than fitting an MGB and further tweaking.
The 1622 is a better compromise and you can take a 1622 out to 1798cc easily, but the MGB unit is the best option for large scale mods. As a rule, a 1622 yields two-thirds the power a 1.8 achieves.
However, it’s not plain sailing. Early three bearing units mate straight to an MGA gearbox and starter motor if you desire an original-looking installation. Depending upon how late you go, the list of new parts grows; a new front plate, back plate, modified fan pulley and fan belt, modified radiator positioning – with more from rubber bumper B engines. It’s not worth the effort for most.
All units benefit from better breathing for and perhaps a session on a rolling road dyno to fine tune what you have already with perhaps sports air filters (£60 K&N) and better carb jets and springs – all worth 5bhp minimum which isn’t bad for a £100 outlay. We’d add electronic ignition too.
Then it’s the exhaust manifold and system to be uprated followed by a bigger valve gas-flowed cylinder head and a hairier camshaft but the latter can spoil what’s best about the B-Series: low rev torque.
If you slot in a hairier cam you may need to look at Weber DCOE carbs although the SUs are okay unless you lust for top end revs. You can get away with single DCOE – manifolds are available. Typically, you’re looking at £700 for respected Stage 2 heads, £400 for a good cam and around £3000 for a nice 1950cc road engine from the likes of MGOC or renowned MG tuning name Oselli.
An alternative, which was a very popular period mod, was a supercharger. MGOC sells a Moss-developed kit, while Peter Edney has made his own set up based on an Eaton unit. Both claim something like a 30 per cent power increase on a standard tune engine but the three grand cost makes it an expensive exercise although it is reversible and an ‘in period’ modification.
Even though the B-Series is as old as the hills, something new always springs up, such as alloy £1000 cross-flow cylinder heads (the standard design is very restrictive), fuel injection and modern ignition mapping and roller rockers, the latter which is a substitute for a cam change – but they can cost £800 and only viable if the old ones are shot.
Fancy something different? Frontline will fit a Rover K series as a turnkey conversion which will cost £13,000 and should yield about 140bhp. Using parts from a scrapyard and a lot of ingenuity it could possibly be done at home for less than a professionally built car would cost, but Frontline are the experts on these MG conversions. Honda S2000 engines have been put into MGAs before but involve a massive amount of structural work. The other option is the Mazda engine we use in the LE50, offering 214bhp as standard with a six-speed manual or auto box. It weighs a mere 84kg so would push an MGA along rather rapidly indeed.
What about an MGA V8? Some years back, we drove one converted by Warren Kennedy (Classic Restorations) using the tried and trusted Rover unit and apart from startling performance seemed tailor-made for the job.
Handling the power
While it sounds logical, fitting the MGB overdrive gearbox presents major issues because it cannot be done without extensively modifying the transmission tunnel. It’s even hit and miss whether the standard seats will fit and even if you strike it lucky, the gear lever still resides too far forwards, claims West. “It’s a messy conversion!” he once told us.
A better option is to fit a five-speed conversion, and the Type 9 box from the Sierra is the most popular but while fitting kits are available, the chassis rails must be in excellent order as these will carry the cross-member for the Ford box. It’s suitable for 1600 MGAs but the 1500cc will need a 1600 engine backplate for the conversion to be viable and even then – as in the case of Morris Minor adaptations – you need decent power (80-90bhp) to be able to successfully ‘pull’ that added ratio. Finally, the transmission tunnel cover will need modifying, and many find the MGA gear lever boot is too restrictive for the Ford shift pattern; use a late MGB gaiter. A kit is available from Hi-Gear Engineering (www. hi-gearengineering.co.uk, Derby 01332 514503) at £850 and it can also supply a gearbox for £745 (that’s for a standard MGA 1500-1600). Cars that are fitted with any combination of MGB engines and clutches can be catered for with parts which they can supply. Peter Gamble at Hi-Gear adds they’ll have brand new gearboxes available during 2017.
That’s good news because, if properly done, this sole mod transforms the MGA driving capabilities, as apart from that additional ratio, the intermediates are better suited to the engine curing the yarning gap between 2nd and 3rd. The other alternative is to up the final drive gearing (the standard spec is a bit low) by using a later MGA or 3.9:1 MGB crown wheel and pinion but in-gear punch will accordingly suffer.
Turning to the suspension, it’s a case of how extreme (read costly) do you wish to corner. Hoyle Engineering (http://www.hoyleengineering. co.uk, Surrey 3932555), for example, offers modern front coilover kits and an independent rear suspension derived from the Ford Sierra if you really want to go mad with your MGA; ideal for those who want to fit high power alien engines, such as a tuned V8. But at over £900 in parts it’s not necessary for the average owner and, besides, such dramatic changes alters the inherent character of the car.
In actual fact, the top MGA specialists advise keeping the ‘back end’ as soft as practicable for a decent ride and more importantly more forgiving handling. MGA guru and racer Barrie Carter further warns against fitting a Watts linkage and Panhard Road to control axle movement for the same reasons. Up front a better front anti-roll bar along with quality lever arm dampers (there’s a lot of cheap nasty recon imports warns West) are all that the typical road user should need to make an MGA pretty spot on. On the other hand, of course, you can go much further for track work including telescopic and coil damper conversions, but again it changes the car’s character – which you may or may not like.
Disc brakes (with standard or EBC GreenStuff pads), naturally from an MGB (or Volvo 200) is doable but it’s not a simple swap plus it requires MGB wheels which look odd. A four-pot front disc kit is going to hit you for over £700 plus you’ll need the hubs, of course to fit, but with only 90-100bhp either the standard drums or their competition alloy replacements suffice (try NTG of Suffolk who has specially-made ones on the shelf) plus look at Mintex’s new line of classic brake linings using modern materials for guidance. But don’t fit servo warns Bob West as it upsets the balance.
Power steering conversions are available, such an MGF derived set up, but not really needed and cost around £3000; opt for EZ electric power steering one if you want PAS as you can regulate assistance. There’s no shortage of wheels or rims and TR6 ones fit okay and look better than MGB ones. Roll along on 165 section, and no wider tyres (Carter recommends the Avon CR65 tyre), for road use.
Basically, it depends how fast you want to make your MGA go – and stop and traditionalists like West reckon many popular and accepted mods are an overkill, claiming that the stock drum brakes are fine if good linings are fitted. Ditto the lever arm suspension set up, using quality units and 400lb springs plus a thorough overhaul of the king pins and trunnions, does the job. “A well sorted MGA still on drums and lever arm dampers is a lovely car,” he maintains.
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