The Original BMW M3

Expert Guide: E30 M3 – Total BMW

I’ve just come back from the BMW Car Club’s November track day at Bedford Autodrome and have reached a conclusion. The E30 M3 is probably the best car BMW has ever built. It’s not the biggest, the fastest nor the most elegant, but at the limit on the track you can experience firsthand what that engine sounds like doing its chuff at the red line and what it feels like to be thrown into bends at whatever speed without the driver fighting the wheel.

You see, the M3 was born for the circuit and I’d be surprised if there’s still a single example that hasn’t done a few fast laps at some point – could you say the same for the E36 version?

History

The M3 was launched in 1986 and it had little, if anything, common with the regular E30. The shell was different with boxy wings front and rear plus a revised add-on rear screen surround to rake it back for aerodynamics, a raised plastic bootlid and a boncled-in front screen. Only the doors and bonnet were shared.

Mechanically, the M3 was also totally different. Special Boge dampers, revised springs and suspension geometry plus thicker anti-roll bars with different mounting points, quicktrack, bigger E28 5-Series inspired brakes with five-stud wheels and hubs meant that nothing can be swapped over individually – it’s all or nothing.

The M3’s engine was the S14 16-valve 2.3 litre unit developed from the M63SCSi’s 24-valve. Based on the M10 engine, this unit used a 10.5:1 compression, steel crank, twin-chain-driven cams and Bosch Motronic engine management to deliver 200bhp. Sat behind this on European-market cars was a Getrag 265 close-ratio dogleg gearbox with direct-drive top, taken from the M535i, plus the 24-valve M5 and M635CSi. Power was fed to a special ZP limited-slip diff with 25 per cent lock up and a tall 3.25 ratio. USA model M3s used a standard pattern 260 gearbox based on the manual 735i unit with the conventional gate pattern, plus a 4.1 ratio diff was fitted.

In terms of standard trim, the early cars used 7X15 BBS alloy wheels while inside, standard Recaro seats were trimmed in the same houndstooth cloth that adorned basic cars like the 316 and 518i. The special instrument cluster used a 260kph (160mph) speedo, and 8000 rpm tacho and an oil temperature gauge where the econometer used to sit. An M-Tech 1 steering wheel, tinted glass and electric mirrors and windows, sunroof and onboard computer were fitted to UK cars.

The M3 was intended to be a volume car to pay for the racing, so they were built at the regular Munich factory in left-hand-drive. The M3 Convertible came along in May 1988 while the first M3 Evo was made between February and May 1987. With 505 built, the 215bhp Evo 1 had brake cooling ducts instead of foglamps, a differently cylinder head, lighter bootlid, deeper front air dam and a small lip under the rear spoiler.

This was followed by the Evo 2 in March 1968 and production finish in May. Numbering just 501 examples, the Evo 2 used different cams and an 11.5:1 compression to reach 220bhp. With remapped Motronic and a lighter flywheel it certainly felt better and the white cam cover and air duct with the Motorsport stripes made it look a bit white socks and shellsuit.

With the final drive ratio upped to 3.15, acceleration stayed the same but the top speed was increased from 146 to 152mph. Lightening of the plastic body parts and thinner glass (except the windscreen) saved 10kg in weight, while the wheels increased in size to 7.5X16. Oh, and it came in Macau Blue, Nogaro Silver and Misano Red only.

Finally we’ve got the Evo 3 Sport, of which 600 were built between December 1989 and March 1990. A long-stroke crank gave the Evo Sport a 2.5 litre engine, and special cams, bigger valves, oil-cooled pistons and sodium-filled vlaves added up to a whopping 238bhp.

Looking much like the Evo 2, the 3 was distinguished by slightly wider front arches, 10mm lower suspension and additional aerodynamic flaps under the front and rear boot spoilers. Add a rubber strip between the bonnet and wings and allegedly reprofiled grille vanes.

Inside, the steering wheel was replaced by a new suede-covered M-Tech 2 version and the new illuminated gearknob and handbrake grip were similarly trimmed. Evo Sport seats were now wraparound buckets with harness holes plus red webbed seat belts. To save weight, the map lights and grab handles were removed and the fuel tank replaced by the 62 litre standard E30 item. Add a plaque inside plus M3 logo sill kick plates and that was the Evo 3.

BUYING THEM

Buying an E30 M3 depends on what you want to do with it, so we spoke to Peter Walsh at PMW (07970 645599) about the pitfalls. You can buy a sound early one for about four grand, have a few laughs and providing you’ve looked after it, sell it on again a year later for the same.

There were very few original BMW (GB) supplied cars around as they were special order, but there are plenty of European imports of varying quality.

Body

The M3 is excellent body-wise but the scuttle can rot in the corners below the screen and, as with any E30 BMW, look in the boot and around the rear numberplate lights for dampness. Doors, arches, and bonnets don’t rot, but it’s not resistant to accident damage so look at all four grand cheapie to hammer around on track days then it’s not such an issue, as long as it’s straight.

Panels are plentiful new and used but don’t expect 20 quid repro wings. Non-working central locking is often down to a failed relay which is hidden inside the A-post behind the passenger’s speaker.

Interior

This isn’t really a problem as so many cars have been trimmed in leather from new or retrimmed. Original cloth is nice though, and it’s rare too. On cars with air con, ensure it works but if it doesn’t and you’re not bothered, it’s not a big job to take it out and refit a second-hand E30 heater unit. You’ll save weight too. Most cars have electric windows and some have electric sunroofs but when do these ever go wrong?

What can go faulty is the electronic heater valve which is shared with the regular E30. They’re cheap, but changing them is a chore. As with any BMW, the service indicator lights can play, but fitting a recon board from somewhere like Hartlake (01634 294115) is cheap and easy.

Engine

The M3’s S14 engine is a work of art. It’s small, light, revs like a food mixer and as well as knocking out at least 195bhp it makes nice noises too. Trouble is, because the M3 was designed to be enjoyed, many have been ‘enjoyed’ that little bit too much.

The timing chain problem have been exaggerated. They rarely break as they are a double-row chain and therefore very strong. The reputation came from the earlier M5 and M6 cars with the single-row chain, which at 100,000 hard-driven miles cold give trouble, but the M3 is better.

The tensioners tend to wear before the chain and these let the chains flap which wears the chain wheels too. Hartlake and PMW reckon that 100,000 miles is a good point to fit a new chain as a precaution and doing it earlier might mean that you can reuse the wheels. Buy a car with 160,000 miles that hasn’t been touched and it’ll need doing. At 100,000 miles, an M3 that’s had oil changes every 6000 miles with good oil should be OK. It’s rare to have a chain let go without warning and they get noisy first. As for the rest of the engine, providing it’s been serviced, the bottom end is fine and the head doesn’t crack.

Running problems are normally caused by air leaks or a dead idle air valve which shorts out a circuit in the ECU, resulting in an 1100rpm idle speed. Air flow meters rarely fail and are specific to the 2.3, but 2.5 units are the same as the M535i’s.

PMW recommend using oils of 10W/30 grade or thicker. Ordinary Mobil 1 and other 0W or 5W oils are too thin and can cause chain tensioner rattle resulting in a £2500 bill from some specialists when a reversion to something like Duckhams Hypergrade was all that was needed. PMW charges about £1200 for the chain job and that doesn’t involve cylinder head removal.

Blowing from the exhaust manifold is normally due to studs unwinding from the head and this is easily put right as arc nasty aftermarket exhausts. New catalysts are silly money but just remove a dead one and sleeve the exhaust. On a track day, add half-a-litre of extra oil or you’ll ruin the engine and PMW are supplying special sump baffles to prevent this. A failed electric fan will be due to the fan switch on the thermostat housing or the ballast resistor in the fan.

Transmission

There aren’t any real dramas here as the M3’s Getrag gearbox was designed to handle more power and torque than the S14 can give. That’s not to say it’s bullet-proof though, and running it low on oil plus serious abuse can kill them. But it takes a lot to ruin one and the first signs are rattling at idle caused by a worn layshaft and crunching into second down from third.

The rear oil seal can leak and many cars need the gear linkage rebuilding. Cure stiff gearchanges by running synthetic gear oil and as long as you don’t murder it, a noisy gearbox can be kept going for a long time.

Brakes, Steering, Suspension

It’s all different from the regular E30, but the M3’s suspension will wear out in the same fashion. Standard dampers are Boge gas and these last a long time plus they give great ride and handling. PMW look after a great number of M3’s that are used on track days and Bilstein shocks with Eibach springs are ideal combination.

They’re a straight swap for the Boge units and when combined with some lower and stiffer springs they become razor sharp on the track but aren’t too stiff for the road. Apart from dampers, the bits to check are the rear subframe mounts, front balljoints plus the front lower wishbone rear bushes.

These parts aren’t very pricey and by doing the work yourself you could return a wayward handling M3 to factory precision for £500. Check the power steering rack for leaks and the column coupling rubber disc for wear. New racks are pricey, but reconditioned ones can be supplied and fitted for around £280 with a year’s guarantee.

The M3 robbed the E28 parts bin for brakes as a lot of it is similar. Discs and pads are cheap enough from BMW and again, many cars have been modified with uprated parts plus braided hoses. Our recommendation? If you’re into track days then a set of expensive brakes is all very well, but for most uses you really can’t beat the genuine article in a BMW box.

If the M3 you’re looking at has got ABS then the light should come on with the ignition but go out when the engine is fired up. If it doesn’t come on then it’s an MoT fail. If it comes on above 60mph there’s problem and ABS parts aren’t cheap, although it’s normally a sensor. A non-working ABS pump is generally a dead relay caused by starting a car’s dead battery with a booster charger.

Running Them

If you’ve bought a nice historied M3 with stamps in the book then why not use a BMW dealer? Despite the mystery that surrounds them, they are a simple car mechanically compared to latest models.

Bridgegate BMW in Chesterfield is the only dealer we know of to come up with specific servicing deals for the M3 and looks after a number of them. What it can’t do, though, is fit aftermarket bits like Bilstein shocks or spiky cams and that’s where your independent specialist comes in handy.

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