The sober looks of BMW’s classic coupe hide its blistering pace. We spend an Eighties-flavoured day with the 286bhp M6
Words Paul Wager • Photography Jackie Skelton

You might have noticed recently that BMW’s 6-Series has quietly shuffled off the price lists. Based on the cutting-edge technology of the most recent 5-Series saloon, it was an undeniably capable car and in 507bhp V10-powered M6 form was a rocket without many equals. But somehow it failed to catch the imagination of the BMW enthusiast and even when prices of used examples dipped to a price an average person could afford, they still weren’t popular with the BMW enthusiasts.

That, of course, is quite a different story from the first 6-Series (E24 in BMW-speak), whose loss was much mourned by enthusiasts to the point where the run-out ‘Highline’ models were pretty sought after. Part of the issue back then was that the car was never really replaced, as its successor was the 8-Series – a softer, bigger car altogether complete with V12 power.

Sure these have a strong enthusiastic following, but the Eights were slated by some as being too soft to carry the mantle of the mighty Six, although that was very much redressed by the BMW Motorsport-developed 850CSi with its 380bhp V12.

So, to discover just what made the original 6-Series so special, we took a pristine example of the range-topping M6 on a day trip culminating in a visit to BMW’s flagship Park Lane dealership for the launch of their BMW Classic venture. Although it would be more correct to refer to the car as the M635CSi – the simpler M6 designation was only ever used in the North American market.

EARLY DOORS
Our day begins at BMW’s UK headquarters in Bracknell, home to the German marque for the last 30 years and coincidentally right opposite the HQ of another middle-class icon, Waitrose. The car in question is a part of the small heritage fleet maintained by BMW UK’s press department and as such has had no expense spared on its upkeep: an important consideration since the 6-Series may be cheap to buy but can be frighteningly expensive to restore. The car park in front of the BMW building is rammed full of its latest models, the autumn sunlight glinting off their sharply creased styling and round here nobody bats an eyelid at the most exotic transport. The old 6-Series though, is different and as it’s brought round to the front of the building for us, the characteristic deep-chested exhaust note has people stopping to sneak a peak.

It’s at this point in our classic drive story that the car owner often tells you to watch for a sticking this or a broken that, but our 24-year old M6 is as pristine as a brand new road test car and we waste no time in spearing off into the remnants of the Bracknell rush hour.

Round here it really is BMW country. Not so much because the firm is headquartered in the town, but because that’s the car of choice if you live in this affluent part of the country, have a decent job and want a car which looks the part. These days though, the crowds of diesel 1-Series, 3-Series and of course new MINIs buzzing around are a far cry from the scene in the late ’80s when this M6 was new. Back then BMW wasn’t anything like the volume seller it is today and the range was much simpler. No SUVs, no MINIs, no 1-Series: just the 3, 5, 6 and 7-Series.

Our car may be 24 years old, but it’s more than capable of keeping up with the modern traffic. The M6 is often described as the result of dropping the M1 engine into the 6-Series, although in truth the engine was slightly revised for the M6 (and M5) application. Whatever the details, the 24-valve 3.5-litre six puts out a mighty 286bhp and since the 6-Series weighs only 1500kg, performance is strong even by today’s standards: 0-60mph comes up in just six seconds and should you fi nd yourself a handy stretch of Autobahn it won’t run out of steam until 158mph which makes it slightly faster than the electronically-limited supercars of today which are all (apart from Porsche) restricted to a mere 155mph...

SAFETY FAST
Bosch’s Motronic engine management means the car runs smoothly even from stone cold and makes these cars as easy to live with as any modern hatchback. In fact, squirting round the roundabouts as we head out towards the M4, the main thing to worry about is not overcooking things and performing an impromptu drift session.

BMW was one of the first makers to adopt electronic traction control but this M6 comes from the generation before that, relying on a good old-fashioned limited-slip diff to keep things under control. The M6 gained 15 per cent uprated springs and specially tuned Bilstein dampers, with a nice predictable feel to the handling that lets you know when you’re pushing a bit too hard. I’m not about to push this example that fiercely but I know from previous experience that the M6 can be made to go very hard indeed in the dry, although it takes a special kind of skill to keep up the pace on a wet road.

Many M635’s – and indeed many BMWs of this era – were supplied originally on the metric-sized Michelin TRX wheels and tyres and although the tyres are still available, the high cost of them tends to put owners off sticking with them. The easy option is to

switch from the 415 mm TRX wheels to a set of visually similar 15-inchers from another BMW and fit cheaper conventional tyres, but the TRX does have its supporters, notably the team at Longstone Classic Tyres, who once spent a long time telling me that if only I could try a car on new TRX rubber instead of the age-hardened semi-slick examples more commonly found then I would be convinced.

And here is my chance: BMW UK’s pockets are deeper than the average owner and this car wears what look like a pretty new set of matching 215/45 TRX GTs. The verdict? Yes, they’re really not bad at all and as a precursor to modern low-profile performance tyres they work well, these fresh examples not presenting the scary sudden breakaway for which they have perhaps unjustifiably gained a reputation.

MODERN LIFE
Spearing down the A329M towards the M4, I’m getting more used to the car, although I’ve driven this particular example a few times before. The throw of the gearshift is lengthy by modern standards, as is the travel of the pedals. But in other respects, it feels very modern – very modern, indeed. The leather-clad sports seats are electrically adjusted via a complex array of buttons on the transmission tunnel, meaning it’s easy to get comfortable and the mirrors are electric too. As we reach the sliproad for the M4, I’m being hassled by a rep in a hurry, anxious to get past me in his Audi diesel. Yes, I know these modern oil-burners can be pretty fast, but as I grab second and wind up the twin-cam six of my 24-year-old BMW, that four-ringed grille rapidly disappears from the mirror. It’s as torquey as you might expect a 3.5-litre engine to be and at lower speeds it’s really very docile, but evidence of the BMW Motorsport input is apparent as soon as you rev it hard – as it gets on cam, it takes on a different, crisper note and comes very much alive.

Our destination is another town redolent of ’80s boom, Newbury where the cellphone giant of Vodafone had its HQ and for many, the mental image of the 6-Series will be accompanied by an estate agent barking into a brick-sized mobile, which makes it somehow appropriate.

At a 90mph motorway cruise, the M6 is in its element, with only a touch of wind noise around the driver’s side window to spoil the party. Blame the frameless design for that and the difficulty of sealing a piece of glass against the roof – later BMWs used an electronic system where the glass dropped down as the door was opened, returning automatically as it was closed to sit inside a seal.

It’s at this point that I investigate the onboard computer which was standard kit in the range-topping M6. All the information you need is displayed here in glorious Sinclair-style red LEDs but rather than by pressing a column stalk, it’s accessed via an array of tiny buttons. I once met the BMW engineer who was responsible for developing this system, who admitted that it was very much designed ‘by engineers, for engineers’. It really doesn’t pay to linger on the average fuel consumption either: drive it hard and that M Power six-cylinder will be getting through the unleaded at a rate of well below 20mpg. Not that it would have been a problem back in 1986 when fuel cost £1.90 a gallon and economy was so far down the priorities that BMW didn’t even have a diesel offering in its UK line-up.

PICTURE PERFECT
We’ve arranged for photography in the grounds of Highclere Castle just south of the town and the understated style of the 6-Series blends right in with the elegant backdrop, to the point where I could just imagine myself in a parallel universe, crunching up the gravel driveway of my stately home in an M6, Roxy Music playing gently on the Pioneer cassette deck.

Magazine photo sessions can be hard work with older cars: panning shots mean you’re constantly accelerating past the photographer, braking, turning round and accelerating again, but the M6 comes from a modern era where there’s no overheating, no squealing brakes and no funny noises from the power steering.

With the photography over, we head back towards Bracknell and our appointment in Park Lane. Keeping away from the motorway, the M6 feels quite different – still rapid, but a real driver’s car too. As we get closer to London the traffic builds and we soon find ourselves in the kind of stop-start jam where a good two hundred of those 286 horses are entirely superfluous. The car may be perfectly happy in heavy city traffic, but the manual box makes it tiring after a while.

Eventually we arrive at our destination and after a day of experiencing the very best BMW had to offer in the ’80s, it’s somehow appropriate that as I stroll up to BMW Park Lane there’s a display showcasing BMW’s heritage. The event is the launch of BMW Classic in the UK, hosted at the Park Lane dealership which is spearheading the firm’s push to provide unrivalled support for its classic enthusiasts. It’s all driven by the ethos that the older cars exist to be used rather than mothballed – something which makes our blast around Berkshire seem entirely appropriate.

FACT FILE

1989 BMW M635CSI
ENGINE: 3453cc, 24-valve, straight six
GEARBOX: 5sp man
POWER: 286bhp at 6500rpm
TORQUE: 251lb-ft at 4500rpm
PERFORMANCE: 6.0secs 0-60mp
158mph top speed
CONSUMPTION: 18mpg
LENGTH: 4755mm
WIDTH: 1725mm
WEIGHT: 1500kg 

VALUES
You’ll pick up a cooking 635CSi for as little as £1000 if it needs work, but the M Power version will always command moreafter all, the engine alone is worth that much to someone who needs a replacement for their M5. Expect to pay £2000 for a rotten example needing bodywork restoration, around £5000 for a usable example needing only tidying and up to £10,000 for pristine examples. The very best cars are knocking £15,000, most of them late model Highlines from 1989.

NEED TO KNOW
BMW Car Club GB
www.bmwcarclubgb.co.uk 

THINKING OF BUYING ONE?
The M635, or indeed any 6-Series from the 628 upwards, is a car to buy with your eyes open because they certainly like to rot. Fixing it is expensive, especially since the front wings run at something like £500 each and sooner or later all 6-Series will need a pair. They rot all along the top edge, down the back edge adjacent to the door and at the front above the front bumper. If it’s caught in time a competent bodyshop can save the day. As for the engine, its motorsport origins make it a tough old thing. The single-row timing chain must be replaced at 100,000 miles, at which point fi tting the updated tensioner from the later M3 is a smart move. The valve clearances should be checked every 40,000 miles and it’s crucial to use the right concentration of antifreeze. Remember though, that if the worst happens, the powerplant is not related to the M30 engine in the regular 635.

Published in the January 2011 issue of Classic Car Mart.

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