What are e31 8 series like.

GazM3 · Post by **GazM3** » Wed Oct 08, 2014 2:57 am

Hey there chaps.
What are the e31 8 series like. Mildly interested in one 1990 850i auto.
Are they relatively easy to convert to manual. Here in Melbourne we can have limited use registration for 25yo cars so this could be doable.

Also had a look at a nice 74 2002 with 5spd ual webers and s14 2.3 crank. Car has door and boot rust though.

Pod · Post by **Pod** » Wed Oct 08, 2014 8:59 am

I've been looking at them for a couple of years, but have not yet taken the plunge!

From what I've been told by a friend who knows these cars well, it appears that the 840 is a better buy, being slightly better on fuel consumption, with little difference in performance due to the lighter engine.

The later 4.4 litre engines are better as the 4 litre had the problems with the Nikasil blocks - however many people consider that at their age now, any issues should have been dealt with years ago!

Having said all that, I desperately want an Alpina V12, 6-speed manual

Brucey · Post by **Brucey** » Wed Oct 08, 2014 12:28 pm

850i or a tweaked 2002? I know which is going to be more fun... but then again, absolute power corrupts absolutely. Or just the appearance of it, even.

The M70 engine (850i/850Ci) is basically two M20s nailed together but with hydraulic lifters and a load of unnecessarily complicated electronic gubbins added. The M73 engine (850Ci) is larger and has another 20-odd dobbins.

The standard manual gearbox is a Getrag S6S 560G and an S6S 560Z will also work I think.

An 850CSi would be fitted with an S70 engine and that is a rare beast indeed.

There is a load of info here

http://www.e31.net/models.html

The M70 motor makes 296bhp stock and even Alpina didn't manage to get more than 350 out of it for road/autobox use (which makes sense in a way; that is exactly what you would get from two mildly tuned M20s).

The E31 is a heavy car. The 850i is claimed to be ~1800kg and the 850Ci is listed at 1955kg. Think of an E24 with four big blokes in it (plus you!). The mechanically related E32 750i is only a tiny bit heavier than the 850i and substantially lighter than the 850Ci with the M73 motor, apparently...

The E31 is a lot more aerodynamic than the E24 so it is ultimately faster at the top end despite the extra weight. Weirdly it is claimed that the E31 shell is actually lighter than the E24 one... so somewhere they just larded it up with a load of heavy luxury stuff. It seems hard to believe that they added over 300kg of it though; even the 840i (which has a lightweight V8 in it) is still listed at ~1800kg weight.

hth

cheers

GazM3 · Post by **GazM3** » Wed Oct 08, 2014 8:11 pm

Thanks for the good description. Lots of gizmos mean lots of potential problems also. Still the e31 I was looking at is not much of a project car where the 2002 needs 7k worth of body repairs. The 2002 appeals as it's infinitely modifiable where the 850 maybe only can put one of wolf's chipset in and stick a manual in there. Still say with 320bhp and manual even if it's 1800kg it will go well. Can also install my 3.73:1 gears to help it out.

sharkfan · Post by **sharkfan** » Wed Oct 08, 2014 8:32 pm

They are a little heavier than 1800kg;

E31 840i: 1,895kg
E31 850Ci: 1,955kg
E31 850CSi: 1,975kg

Brucey · Post by **Brucey** » Wed Oct 08, 2014 9:06 pm

there is a whole load of electronic/display stuff that routinely goes wrong in the E31 (like many other BMWs of the period) so you need to check everything very carefully to be sure it works.

I forgot to mention; the manual gearboxes are rare; Getrag sold their remaining stock of new gearboxes off a few years ago and don't intend to make more boxes or spare parts for them. They can be rebuilt at present but presumably at some point some spares will go NLA and won't be replaceable.

Some folk have made an adaptor by rewelding an autobox bellhousing; the stock autobox is a ZF4-HP24-EH and has a removable bellhousing; this makes a good starting point for attaching 'something else'.

In round numbers a stock E31 850i has about the same power to weight ratio as a 635CSi. A 250bhp E24 would be a close match for a 320bhp E31 up to ~100mph but the E24 would probably be quicker in the twisty bits.

7K of welding on a 2002? Hmm... I'd take that as an ideal opportunity to learn to weld, myself. I can't see how you could spend that much on just the boot floor and the doors...?

cheers

GazM3 · Post by **GazM3** » Wed Oct 08, 2014 10:24 pm

Haha I'd live to have the time to do it. There is rust in the doors lower wings arou the top of the boot trim and Wherever else. Would be 7k with fresh paint can get car for 3.5k and another few k of tidy ups. Good 2002's go for 15-20k here locally.

With the 850i can get for 12k prob
Needs 2-3k of fix ups. Most good condition 850's go in the low to mid 20's. With a factory manual they would be worth 25-30k easily.

bfons · Post by **bfons** » Thu Oct 09, 2014 6:08 pm

After 4 6ers, and my love affair with the E31, I finally took the plunge a few years back.

It took me about a year of half ass looking to find the one I wanted. I wanted a Manual, 850, the right color combo, the right condition, service records, etc.

I finally *settled* on the Black/tan 1995 840ci. Yes it was an auto and an 840 (not the 850 I wanted) but at the end of the day, V8 isn't much slower than the V12.

As much as I wanted a manual tranny, I'm now ok with the Auto.

To answer your question... "What are e31 8 series like?"

Picture a car that can float smoothly on the highway or run up the Mountain twisties with no problem. A car with timeless lines. A car that gets looks and thumbs up everywhere you go....

That's what an E31 is like...

Now the negative

Be prepared to tackle electrical issues.

henryc · Post by **henryc** » Thu Oct 09, 2014 6:19 pm

I agree with Brian. These are one of the coolest cars.
I've owned my 91 850i for three years after lusting for one since 1991. As usual, buy the very best example you can find from someone who had the means to support its service and repair requirements.
It helps if you know someone with a BMW GT1 for diagnostics - a big help and better than guessing what's wrong. Like Big Coupe there is a strong 8 Series group- you can find them on bimmerforums E31. There is also a BMWCCA chapter now exclusively for the E31 folks-
http://bmwccae31.com/

When I'm in my garage, I can't believe I'm so lucky to own both an E24 and E31. / henryc

henryc · Post by **henryc** » Thu Oct 09, 2014 7:53 pm

Forgot to mention-
The 850's take two of everything-
two batteries (in the trunk)
two fuel filters
two air filters
two ign coils
two dist caps/rotors
two cabin filters
but just one oil filter

If you do regular maint and service on your E24, you can easily do the same on the E31. I read where they say you have to remove the intake manifolds on the V12 to change the spark plugs, but this is not true. I have full access to both banks- standing in front of the engine, leaning over and slide my hand in on each side. Plenty of room.
Although these cars are now 'vintage' I get lots of comments about "is that the new BMW".......
/henryc

Post by **bcadmin** » Thu Oct 09, 2014 8:00 pm

Uhhhh...

I had to change both batteries since I didn't use a trickle charger. I'll never make that mistake again

And it is funny. I've been asked a few times "Is that the new BMW?"

Post by **bcadmin** » Thu Oct 09, 2014 8:01 pm

And another no brainer

Like the E24

Don't expect to haul anybody around in the rear seats

GazM3 · Post by **GazM3** » Thu Oct 09, 2014 8:33 pm

I really like the look of the 8 series. They look super cool and in Australia the numbers were so limited that they will hold their value and even climb. I've heard electrical bad stories for all bmw's but I guess with 2 of everything the v12 is especially complex.

The problem is the "best ones available" are like 20k more. The one I was looking at is about 7-8l underpriced. I do t generally buy my cars as speculators to sell but it's nice to if you have to sell them you make money rather than lose.hmmm. Decisions decisions.

cecotto479 · Post by **cecotto479** » Fri Oct 10, 2014 8:43 am

I've always fancied one, but never had the bottle to buy one.

I worked on the view that if one came up at a price that I could afford to "take a punt" on it on the basis that if it went tits up, I could stomach just binning it, then I'd go for it. But the possibility - or probability - of horrendous repair bills meant that even a "good" well historied one was just too much of a financial gamble and a dead one was just worthless.

Prices in the UK at least are beginning to firm up a bit and well historied, tidy one are on the up. The 850 Csi is definitely the one to buy to keep if you can find a good one. A cheap early 850i would still do the job if you just fancied a bit of short term E31 action.

I am astonished by M Coupe prices in the UK just now too. I saw one at a classic car auction a few weeks ago make the sort of money you'd expect to go into a franchised dealer and pay for it. If you want one of them, buy now.

sharkfan · Post by **sharkfan** » Fri Oct 10, 2014 9:16 am

cecotto479 wrote:
I am astonished by M Coupe prices in the UK just now too. I saw one at a classic car auction a few weeks ago make the sort of money you'd expect to go into a franchised dealer and pay for it. If you want one of them, buy now.

I take it you mean M6/M635 prices - I'm not so surprised, prices have slowly risen to about two years ago then taken off - the prices of rotten projects has now risen to nearly the price of a half-decent car from 10 years ago and those in the know or have BTDT with regard to E24 restoration costs have already snapped up most of the good/restorable/saveable cars.

cecotto479 · Post by **cecotto479** » Fri Oct 10, 2014 5:56 pm

I said "M Coupe". That's what I meant. If I'd meant M635 CSi that's what I'd have said.

GazM3 · Post by **GazM3** » Fri Oct 10, 2014 9:38 pm

Lots of old bmw's have risen significantly in the past 2 years.
E30 325is over 15k
E24 635csi 18k m model 30k and up
E31 840 850 25k and up
2002 15k and up
Even the humble e35 m3 is 15k and up.

There has been movement upwards of e28 and e34's.

The only cars falling is the e34m5 and the later model m models are still nosediving. Mid 20's gets u an e46m3 which is about te same money for an good e36m3 Evo.

Our exchange rate is about 0.87 to usd and 0.57 to uk pound for comparison.

Overseas it seemed the classics are about the same but the new models depreciate even quicker.

cornershop · Post by **cornershop** » Sat Oct 11, 2014 11:19 am

I was weighing up an 840 before I bought the E24; I was also comparing it with a 928s2 but I was scared off in both cases by potential horror stories re electrical gremlins - yes,I believed what I read on the internet.

Too late for me now, but something like this would have ticked all of my boxes

http://bicestersportscars.co.uk/car-sal ... 8-s2-auto/

ron · Post by **ron** » Sat Oct 11, 2014 3:09 pm

cornershop wrote:http://bicestersportscars.co.uk/car-sal ... 8-s2-auto/

That is a lot of money for an S2. I've been looking for a GTS for quite a while now. I shall find the right one day.