Buyer’s guide: BMW 8 Series (E31)

By Malcolm McKay

| 24 May 2019

Classic & Sports Car – Buyer’s guide: BMW 8 Series (E31)

Why you’d want a BMW 8 Series (E31)

Unpretentious yet supremely elegant, the 850 was one of the most subtle super-GTs, with a remarkable 0.29 drag coefficient. This ultimate autobahn-stormer could cruise all day at 150mph, delivering the driver relaxed to their destination thousands of miles later.

Never really a sports car, even when BMW added a six-speed manual ’box and M-technic suspension as options, it came closer when the phenomenal CSi was launched in 1992 – after which the 840 joined the range as the entry-level model.

It feels vast on British country lanes and is laden with sophisticated comfort and driver aids: the CSi featured rear-wheel steering, traction control, electronic dampers, a 5.6-litre V12 engine and an adaptive gearbox.

The ultimate Alpina B12 5.7 manual boasted 416bhp; there was also a B12 5-litre automatic with 350bhp. The majority were 840s and most were automatics.

Official figures show that 3040 came to the UK, of which 850 were V12s. DVLA records cast doubt on that, showing 1215 V12s registered in 1999, but, equally surprising, just 306 left in 2011. Some have been crashed and others broken for spares, but surely not so many?

Of the V8s, the DVLA’s highest figure was 2001 cars; now it’s 1259, a more plausible depletion rate.

(l-r) Late-model 840Ci Sport handled better on stiffer set-up; David Hockney paints CSi, with muses Stanley and Boogie

They are extremely tempting as a classic buy. Prices have shot up in recent years, but you can still get a rough 840 or 850 for under £10,000, and a good one for less than £20,000, and cars of at least 20 years old are eligible for cheap insurance.

The 4-litre is arguably the best value, often better equipped than the 4.4s. Though officially limited to 155mph, most cars will go faster. Of course, the more complexity, the greater the danger of getting your fingers burnt but, because these cars were so well made, if you find one that has been properly maintained and cherished, there is little danger of being hit by horrific bills. That sub-£10,000 car, however, could easily cost another £10k to bring back to a decent standard.

Corrosion is unlikely to be a worry, but check for poor past repairs and, if the paint is fading, remember that resprays are not cheap. High mileage is rarely a problem: neglect is the main enemy and irregular use can wreak havoc, especially if the car is stored in damp conditions.

And don’t be taken in by a vendor saying: “The dash displays aren’t working, it’s probably just a fuse.” More likely, he tried to jump-start it and blew an £800 control module. Boffins can rebuild them for less, though it’s still a costly repair.

BMW 8 Series (E31): what to look for

Bodywork

See above for trouble spots

Engine

The heart of every 8 is a superb V12 or V8 engine. Look for oil, water and clutch-fluid leaks, plus non-standard parts, signs of tampering and recent major work that may not have been done properly. Fully synthetic oil is best avoided: it’s too thin and is consumed rapidly. A full service history is a big bonus, reflected in price.

If water level drops, air locks form and need a specialist fix – otherwise head gaskets can blow, leading to major problems if not repaired promptly.

Gearbox

Automatic gearbox problems are rare; its specification is better on later cars. Manuals can become notchy, though this can be rectified for £600-800.

Wheels

BBS split-rims are costly to restore properly: budget £250/wheel. Other types are a little less trouble. Quality tyres are vital: cheap brands can fail.

Interior

Most driver’s seat side bolsters have worn through, and the foam behind often breaks down. Budget £250-350 to replace worn panels and re-colour.

Most dash displays have lost pixels: a repair costs c£75; replacement c£330. Check that it all works: a jump without spike protection kills costly electronics.

Lights

Check pop-ups operate and reflectors are in good order. Dipped beam is very poor; HID upgrade with ballast in loom transforms it (£250 from Chris Burton).

BMW 8 Series (E31): on the road

The 8 Series has complex electrics, but the engines can go for miles

These were some of the first cars with ‘fly-by-wire’ throttles. They are packed with ECUs, each of which can cost hundreds, if not thousands, to fix if they fail. Viscous fan, water pump and cam-cover gaskets are common failures, needing hours of work to replace. Beware oil leaks from the upper and lower sump, plus timing-cover gaskets on V12s: £1500 minimum to do the lot.

Engines are immensely durable. The Nikasil liner problems on 4-litre V8s have virtually all been sorted and 180k miles without problems is not unusual; some V12s are up to 220,000 miles.

To check for a misfire, select park/neutral with the engine warm and ticking over, then floor the throttle and lift off – as the revs rise, listen for an uneven note. On the test drive, doing 30mph, accelerate hard and look for smoke behind. Poor running is often down to ageing Lambda sensors or throttle bodies out of sync, though it could be valves, stem seals or low compression.

With two tons and huge performance, bushes take a pounding: those in the front brake-reaction arms, plus rear top damper mounts and hubs fail (six-seven per side): listen for clonks, look for odd tyre wear and feel for wayward handling. New electronic front dampers are £800 each, but £150 inserts are an acceptable substitute.

The brakes should be excellent, but calipers stick on infrequently used cars. Automatic Stability Control units can leak – replacement is £3000 unless you can find a second-hand one. On a CSi, check that the rear steering works; you can feel it on roundabouts or tight corners. The £3k actuator solenoids seize, but can often be freed.

BMW 8 Series (E31) price guide

CSI

Show: £50,000+
Average: £30,000

850i / 850Ci / 840Ci

Show: £25,000+
Average: £10,000+
Restoration: £6000+

BMW 8 Series (E31) history

1986 Two-year development of 850i completed, but launch delayed due to strong 6 Series sales

1989 8 Series E31 introduced

1991 UK right-hand-drive sales begin

1992 850CSi added: 5.6-litre, 375bhp, manual only, improved aerodynamics (based on stillborn M8), new interior. Alongside 830Ci: 3-litre V8, 215bhp (not sold in the UK); 850i renamed 850Ci

1993 840Ci replaces 830 (18 built): 4-litre V8, 282bhp, five-speed auto or six-speed manual; electronic suspension option on 840 and 850

1994 850Ci gets 5.4 V12; airbags standard

1995 Servotronic power steering fitted

1996 850CSi production ends

1997 8 Series withdrawn from US market due to poor sales; 840CiA Sport special edition launched in UK, with adaptive auto gearbox

1999 Production ends

The owner’s view

Owner Chris Burton turned his passion for 8 Series cars into a business

“I bought my first 850 10 years ago,” says owner Chris Burton. “I love the preposterous V12 and the look of it: a good example is sublime to drive. It had always been a dream and finally prices were affordable. A couple of dashboard bulbs failed, so I took it to my local BMW agent: the parts were £1.75 and labour was over £400.

“I saw an opportunity: I began my career in the motor industry and set up a specialist 8 Series business – and I’ve never looked back. I went on the forums, answering questions. We keep growing and I’ve owned dozens of 8 Series cars in that time: currently I have a white 850 awaiting restoration.

“We’re enthusiasts first and foremost and often spend an hour talking with customers before we look at their cars.”

Also consider

Porsche 928 (left) and Jaguar XJS are alternative buys

PORSCHE 928 S4/GT/GTS

The final 928s had good handling and performance, but the ride was poor and, compared to the BMW, they lacked sophistication. GTS holds its value well; earlier cars are cheaper but often high mileage.

Sold 1986-’95 • No. built 20,725 • Mpg 15-23 • 0-60mph 5.4 secs • Top speed 168mph • Price new £72,950 (GTS, ’95) • Price now £17,000

JAGUAR XJS 6.0/4.0

The runout XJS was refined and rapid: it didn’t match the BMW’s ultimate equipment levels, but that makes it a less scary prospect to own today. Few 6-litre V12s were built; 4-litres are thriftier and plentiful.

Sold 1989-’96 • No. built 17,693 • Mpg 14-22 (6.0) • 0-60mph 5.8 secs • Top speed 161mph • Price new £50,500 (6.0, ’95) • Price now from £6000

BMW 8 Series (E31): the Classic & Sports Car verdict

The 8 Series has gone up in value recently

Unless you’re an electronics expert who also enjoys a challenge, go for as good an 8 Series as you can find and look after it: it will reward you with stunning looks and a consummate driving experience.

Buy unwisely, though, and you could spend many times your modest investment putting it right. They’ve gone up in value considerably over the past five years or so, but you’re still better off buying the best.

FOR

Superb, timeless appearance
Phenomenal performance
Outstanding build quality

AGAINST

Expensive to repair; parts pricey, too
Extremely complex, so not a DiY prospect
Useless rear seats

BMW 8 Series (E31) specifications

Sold/number built 1989-’99/30,621 (including 7803 for 840 & 18 for 830)

Construction steel monocoque

Engine alloy, ohc-per-bank 4988/5379/5576cc V12 or 2997/3982/4398cc V8, with EFI; 282bhp @ 5800rpm-380bhp @ 5300rpm; 295lb ft @ 4500rpm-406lb ft @ 4000rpm

Transmission six-speed manual or four/five-speed automatic, driving rear wheels

Suspension: front MacPherson struts rear five control arms, coils; telescopics, anti-roll bar f/r

Steering power-assisted recirculating ball, with 3.4 turns lock-to-lock

Brakes 123/4in ventilated discs, with servo

Length 15ft 8in (4780mm)

Width 6ft 1in (1855mm)

Height 4ft 43/4in (1340mm)

Wheelbase 8ft 91/2in (2684mm)

Weight 4152-4354lb (1885-1975kg)

0-60mph 5.6-7.2 secs

Top speed 155-170mph Mpg 13-22

Price new £56,850 (840Ci, 1995)