The joy of the original BMW M3 of 1986- ’91 is how it begs to be driven. This screaming little four-pot, known in BMW-speak as the E30 version, is fast, agile and forgiving – like a grown-up Mini Cooper ‘S’ or a Caterham Seven with a roof. It’s also a great bargain – £10,000 buys a good one – that should prove reliable an not much more expensive to run than a humber 318i. Tempted? Mark Hughes explains how to buy this left-hand-drive sports saloon of wondrous virtues and few downsides – Classic Sports Car
Body, style and interior
There’s more than a touch of Q-car about the original M3 Aerodynamics features – front air dam, raked rear window, wing on the tail – distance it visually from a standard 3 series, but most people wouldn’t believe this unassuming saloon can hit nearly 150mph. As these cars grow older, one great virtue becoming clear; they suffer little corrosion. Although early ones weren’t quite as well rust-proofed, all M3s last incredibly well and any rot that develops is trivial. Accident damage accounts for the only significant bodyshell problems, as poor repairs trigger rust. Spotting the tell-tale signs of a shunt sometimes needs and practised eye – so it makes sense to have an expert assessment. The worst scenario is to buy; without realising it, an M3 with a twisted bodyshell or front chassis legs that are visibly out of line.
There are no problems over parts available because everything can still be obtained through BMW. Better still, the original M3 is the cheapest to run of all BMW Motorsport cars. The four-cylinder engine is simpler to maintain than BMW’s ‘six’, and so much of the running gear is pure 3 series. The car’s trickery lies not in masses of special components, but in the ingenious way that BMW contrived the design from mass-produced building blocks.
Technical and mechanics
Clever engineering created a little jewel of an engine for the M3. As found in all E30 M3s apart from the Evo III, the 2302cc four-cylinder unit shares its 93.4mm bore and 84mm stroke with BMW’s 3.5 litre ‘six’, which was used in four-valve form in the M1 and M635CSi. So it was created as essentially a four-cylinder derivative of an existing race-proven ‘six’, with a shortened version of the bigger unit’s four-valve head.
The incredible thing about this engine is its bullet-proof record, despite the ability to develop nearly 100bhp per litre and rev its heart out to 7000rpm. It’s generally cheaper to service than any BMW ‘six’ and just as robust. But the timing chain assembly must be replaced at 100,000 miles, even though this isn’t on the factory service schedule. Lots of M3 owners have learned this the hard way by having to fork out £4000 or more to rebuild an engine full of bent valves and damaged pistons. If this advice is ignored the timing chain will eventually fail without warning, sometimes when starting from cold. The chain tensioner relies purely on oil pressure, so chain backlash can occur when pressure is low and cause the chain to jump a tooth on the crankshaft sprocket. Using a relatively thick oil (10/40 Castrol GTW Magnatec is ideal) is important because the engine runs quite hot (about 100 deg C), causing the oil to ‘thin’ and encourage chain backlash. Any timing chain rattle indicates use of the wrong oil – even though it might be of high quality – not problem with chain.
Timing chain replacement sensibly goes hand-in-hand with a top-end overhaul (usually just valves and seals) and costs £2000-£2500, but the unit should then sail on for another 100,000 miles. First time round the clock there’s hardly any bore or crank wear, but some bottom-end work (crank bearings, oil pump and possibly pistons) becomes necessary at 200,000.
M3s run very rich when cold – the individual butterfly housings pour in a lot of fuel – and flood easily. Apart from the long-term effect of fuel getting into the oil and thinning it, the engine can also drop to two or three cylinders. Don’t blip the throttle: hold the revs at 2000rpm and it will slowly clear. If the car won’t start, the plugs will have to be taken out and cleaned. Hunting at low speeds is often caused by air leaks through the thick rubber block that cushions the inlet manifold. This block typically needs to be replaced every two years at a cost of about £250.
Misfires are often caused by cracks in the distributor cap or a burnt-out central electrode. On the four-branch exhaust manifold, check that each branch is secured to the block by all four studs, as these are prone to falling out or snapping off. The radiator construction, with a plastic header and metal core crimped together, can lead to leaks, indicated by white staining. There may also be signs of leaks around the water pump, which starts to develop play beyond 60,000miles. Alternator alignment changes as bushes perish and the belt can get thrown off the pulley at high revs. Optional air condition is very reliable but expensive to repair when it breaks. Check operation of the electric fan, which is single-speed before 1988 and two-speed thereafter, failures are quite common because wires can snap.
So much of the M3′s exquisite finesse as a driver’s car depends on mechanical integrity, above all on the chassis side, that it’s pointless buying a car that hasn’t been properly maintained. The good news is that most have, as the typical owner Is a knowledgeable enthusiast who’s not short of a bob or two. It’s not that an M3 is particularly expensive to maintain, but rectifying problems on a neglected one can lead to some hefty bills.
The moral, then, is to buy the best you can afford. That means spending £9500 minimum from a dealer of £8000 as private buy. Any less raises the likelihood of greater long-term expenditure on things such as suspension or gearbox synchros. As Barney Halse of Munich Legends, the principal source of wisdom for this Best Buy, says: “We won’t sell £7995 M3s, but we do repair a lot of them.” Remember, too, that £2500 needs to be set aside for timing chain renewal on any car approaching a six-figure mileage. History is important, but there are better credentials than a fully stamped service book – almost M3s were well looked after by BMW dealers in their early days. More telling is the recent pattern of maintenance and use: the better buys come from enthusiasts who sometimes choose to entrust their car to a specialist rather than a factory dealer.
Don’t be too fussy about which model to choose. One of the special editions or the ultimate 238bhp Evo Sport would be a desirable possession, but the best car to buy is the one in good condition at a fair price. Extra power and chassis tweak may be worth a few tenths of a second on the track, but a humble D-registered non-Evo is just as much fun. Long term collectability, however, favour one of the short-run derivatives. It’s necessary to be sure that an M3 will suit you. If your regard for BMWs is centred on silky-smooth, torquey six-cylinder engines, you’ll probably hate a rough, gruff little four-cylinder engines that delivers nothing much below 4000rpm. Neither is the M3 sensationally fast, because, above all, it’s a handling machine: a TVR might be better if you want a real grunt. Cabriolets are worth the most, typically fetching about £2000 more than an equivalent saloon. The purist might not like the loss of body rigidity, but there aren’t many open four-seaters to match a ragtop M3 for speed, style and handling – great for summer days out with the family or friends.
Buying in Germany, where most M3s were sold, may be an attractive idea if you know what you’re doing – especially at current exchange rates – but you could come a cropper. There are cautionary tales of £5500 M3s brought back from Germany that then need horrendous expenditure to put them right.
There’s only one way you can go wrong with an M3 and that’s to spend too much money on the wrong car. Bright paint and blacked-up tyres can make any tired old car look wonderful, and this happens with M3s too. A well-maintained example isn’t costly to run, but rectifying all the wear and tear on neglected cars does get expensive – and the robustness of BMWs means that some owners skimp on maintenance.
The ideal M3 is a cherished specimen, owned by an enthusiast and with good history. You’ll get a glorious driver’s car that’ll be spell-binding to hustle along your favourite roads.