MGB

Magazine Subscription

Subscribe to Classic Motoring Magazine and save over 20%

Subscribe NOW

Available at all good newsagents including WHSmith

Fifty five years on and the MGB still comes up with new surprises and with modern tuning tricks

Think you know how to tune and improve your MGB? Well think again because, like the evergreen Mini we covered a few issues back, there’s always something new to put the sting back in to a B – so don’t turn the pages just yet! MGBs can always be made into a fun sports car with just a few tweaks, some old, some new, some cheap and others not but at least there’s something for everyone wanting to make the most of this MG. And that includes you!

Before you start

There are so many MGB buying guides we needn’t go into specifics here; chances are if you’re buying a car to hot up you’ll know what you’re looking for and want to replace a lot of things anyway – a good bargaining point on an average car of which many are about.

Naturally, the big enemy with these cars is rust. MGBs were amongst the first monocoques made by BMC, and as such they were over-engineered to ensure they didn’t fall apart – but they still rot for England! The sills are particularly bad areas – there are seven pieces, and if the whole lot needs replacing it’s £740 per side to have done, and done well otherwise the doors won’t shut properly. In particular, the castle rails must be solid or the whole thing will flex, wobble, and safety will be compromised. Wings rot out too, as do inner wings in the engine compartment (they go all squishy) when pressed firmly. Check the suspension mountings closely; chances are if you’re going to give it more go it’ll be driven hard, and these areas will be put under more strain than normal.

Bear in mind that you can buy brand new shells from British Motor Heritage. Not a cheap exercise but there again nor is professional body repairs. Another good point is that BMH can supply ‘competition’ shells which are strengthened where necessary.

Mechanically, there’s almost nothing to worry about, however and anyway as we said earlier, a lot of the old running gear will probably be replaced (easy to sell on) in the quest for more of a B-sting.

Hotting up

There are so many MGB specialists and so many performance mods for the B-Series that we’d run out of room if we listed them all but, unless competition rule dictates otherwise, recommend a fivebearing unit for anyone looking to considerably increase power even though the earlier unit is freer running.

Budget tuning works well by centring around better breathing with the likes of K&N air filters and a sports exhaust, including manifold. This £3-£400 spend should liberate around 10 per cent more power – plus, we reckon, another 3-5bhp if you have the engine fine tuned on a rolling road to get the optimum mixture and ignition timing settings for that set up.

Want more go? Larger valves and gas-flowed ports always work wonders on the B’s cast iron head along with a CR of around 9.5:1 (don’t go higher), but think twice before installing a too racier camshaft (and there’s plenty to choose from) as it compromises what’s so good about the venerable B-Series – torque.

One alternative is to a roller rocker train which give a similar effect without an engine strip. Gas-flowed heads with alternative carb needles and springs should see an extra 10bhp – more on rubber bumper models as valve sizes were reduced – for around £6-700. According to the MGOC, there’s rarely any need exceed 1.75in SU carbs, unless it’s for serious race tuning, ditto DCOE Webers, although such a spec should see around 140-150bhp; nice but may be too race-like for road use. Supercharging has always been popular and this simple bolt on tweak can yield just as much bhp for around £3000 – try Moss or your MG specialist or MGOC for advice.

The stock five port head is hugely restrictive and if you have the money aftermarket eight port heads are available and there’s the option of a much lighter more efficient alloy head from Webcon for around £900 – the ultimate being a crossflow head design. The MSX is a fabulous bit of kit but you’re talking in the region of £1000 (sans valves and springs) depending upon spec and naturally the rest of the engine has to be A1 to cope with it.

Best and easiest route which, according to the MGOC, most owners now opt for, is a ready to drop in tuned engine. Two litres is the optimum size of a B-Series for road and track. Oselli sells a 1950cc engine which runs on unleaded in the region of £3000 (http://www.oselli.com) while the MGOC markets a a similar unit at just £2130; you pays your money… A 2.1-litre tune is also on the cards but this is said to provide a weaker (strengthwise) if punchier 140bhp engine and not recommended for reliable daily use but if you like the sound of this spec, MGOC will sell you one for around £3500.

Going further there’s several fuel injection and electronic mapping for the MGB, again Webcon can supply both. The Alpha mapping kit, which uses normal carbs, costs in the region of £600 and allows racier camshafts to be used successfully by ‘filling in the gaps’ they cause in the rev band plus provide a much smoother tick over and low speed running. Another option is the bolt on Mikuni carb kit from Moss.

Discussing distributors, the MGOC advises electronic ignition (who doesn’t these days?-ed) and preferably the popular 1-2-3 or Aldon types.

Ignoring going the obvious if sensible V8 route, Rover’s T series, a direct descendant of the B-Series, fits in the engine bay to a T and gives up to 200bhp in stock Turbo tune and half as much again when tweaked. We’ve heard of Triumph straight-six conversions for a different sort of MGC, but this messes up the weight distribution and affects the handling. A much better bet is Rover’s crisp K-series. Frontline does conversion kits where a turn-key car could be supplied from about £15,000. But you could build your own for less; MGF units can be sourced from £250 then hooked up to a Ford Type Nine five-speed box. Whilst it’s not an uncommon conversion, it’s still pleasingly different from the norm.

Sierra Cosworth engines have been shoehorned in along with the Fordderived Mazda engine, which formed the basis of Frontline’s magnificent MG LE50 – and there’s nothing to stop you building a replica. The cheapest way would be to buy a decrepit or crashed MX-5 as a donor car; for as little as possible if you’re particularly handy with the spanners.

Handling the power

It sounds strange to talk about cosmetic mods in a section on handling, but if your MGB is a rubber bumper, converting to chrome relieves it out over 40kg from either end at a stroke and will make the car slightly quicker and better in the bends.

By the same token, Webcon’s alloy cylinder heads also shave a useful amount off the car’s noseweight to promote better weight distribution, so there’s a further benefit of this costly upgrade. Rubber bumper cars need lowering, that goes without saying – but leave the standard B alone, advise the seasoned experts.

A general lowering kit would be in the region of £200-£250 (or £32.50 from the MGB Hive to simply remove the r/b’s suspension blocks!) although bear in mind that at the front the r/b front crossmember differs to chrome car’s one and won’t fit without altering the steering’s geometry unduly (speak to an expert).

Making an MGB get round corners quicker, safer is not new or rocket science and there’s a host of upgrades depending upon your budget and bravado but always start with uprated dampers; telescopic dampers, particularly at the stern, are best of all even though the ride quality will suffer. Stiffer springs are the next step but again, refinement suffers unless you opt for the latest ‘Parabolic’ type of rear springs which are a good compromise if ultimate handling is not the ultimate goal – if it is specialists such as Hoyle and Frontline market modern complete independent rear ends with coil springs and telescopic dampers at close to £2000.

Like the smaller brother Midget, keeping the rear axle in check is essential. A simple Panhard rod kit from the likes of the MGOC and Frontline does the trick and cheaply, at £295 and you also add anti-tramp bars.

MGB experts say to sharpen handling, thicker anti-roll bars are essential, which, in conjunction with telescopic dampers (try SC Parts Group), transform the car’s dynamics for just £100 or so. Go for 3/4inch one for road use. The two-part rubber bushes fitted to the front wishbones are an absolute abomination, and if you are looking at improving the handling of your car these should be ditched in favour of the beefier V8-type bushes – either rubber or better still uprated polyurethane.

The ultimate front set up also involves a ‘coilover’ telescopic conversion that comes with a top wishbone assembly (which can be removed at any time to return the car to standard). When fitted, a more positive ride, lighter steering, responsive suspension and, the ability to adjust the ride height are some of the rewards. There’s a variety of kits for road and track costing from £625 with the ultimate being MGOC’s Evo3 front axle at nearer £1500 or Hoyle’s broadly similar idea closer to £2000. Pricey, but as you need to overhaul these components anyway, it can become fairly cost effective.

At the very least, fit EBC Greenstuff pads or similar – we found a set of MGB pads on a well known auction site for just £33.95. More expensive are bigger anchors with four pot callipers; the R V8 front axle set up is considered ideal for this purpose if you have the funds. Rear discs conversions are available (try Frontline) but aren’t really needed for most road work although braided brake hoses give a better pedal feel.

When the MGB was launched, crossply tyres were the norm and the suspension’s castor angles were accordingly set up for them. However, even with the advent of radials they remained unchanged until 1974. A castor reduction kit from the likes of Brown & Gammons and Frontline reduces the angle of the dangle to more acceptable levels to lighten the steering and reduces the ultra strong self-centre action although it’s still heavy at parking speeds. At £90, it’s also a darn sight cheaper than power steering which typically costs ten times more. Talking of which, the MGOC has changed from its original Peugeot-rack and pinion electric kit to mechanical, because it provides a better feel says the owners’ club.

As an aside to the above are negative camber conversion kits. Moss Europe says these wishbone arms are recommended for road use and essential for competition as they improve turn-in. Once installed, the tracking must be corrected; Moss recommends a toe-in of between 1/8 to 3/32 inch. Good value at around £60.

You don’t really need five-speeds if your car has overdrive – as most have. Boasting six-ratios, it’s as good as a five-speeder, although the latter is better suited for track.

The Rover LT77 box, taken from the SD1 and the Sherpa van fit while Ford’s perennial but increasingly scarce Type Nine box has a rival in the shape of the MX-5 gearbox, care of Mazda itself and specialist Vitesse to market a fine BMH-approved alternative that is said to boast better ratios and a brilliant gearchange and what’s more, the B’a floor doesn’t need major modifying. A bit cheaper than a typical Ford conversion, at £2900, there’s also the distinct possibility of six-speeds but the clutch hydraulics need altering to accept an internal slave cylinder. So you see, the MGB keeps on buzzing!