840ci vs. 850ci reliability, maintenance costs, and market value, all else equal

[Dash01]

In a side by side comparison of E31 840ci vs. 850ci with all else (i.e., color, condition, mileage, etc.) being equal, which model would typically be:

1. More reliable, especially as a daily driver?

2. Cheaper to maintain?

3. More valuable in an open market?

[Timm]

In my experience of the 840ci - only 5% of problems are engine related, 95% is the rest - and the rest is shared across all models!

[Coupenut]

In my experience with the 850i I haven't experienced any problems or issues that I can point to and say are unique to the 850 or even the 8 series. Every repair or maintenance item that I've dealt with I would expect to experience with any other BMW of similar age, mileage, or maintenance history, except of course the "two ofs" battery, and distributors. That probably gives me the same type of experience as Timm.

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[TedBobo]

In my experience of the 840ci - only 5% of problems are engine related, 95% is the rest - and the rest is shared across all models!

Same with my 850Ci.

[rjbaren]

I personally prefer the V8 to the V12.
The V12 boys call us four short, but in reality it comes out in the wash. V8s have 4 cams and 4 valves per cylinder. V12s have 1 overhead cam per bank, 2 cams total, and 2 valves per cylinder.
You can buy a 6 speed 850. It is easier to convert an 840 to a 6 speed than it is to convert an 850 to a 6 speed.
I don't care for two distributors and wires and plugs. You get 8 coils with the V8.
Seems like you have to remove the intake manifolds on the V12 ( I may be wrong about this) to do some maintenance and you don't with the V8.
Drive by wire on the V12, throttle cable on the V8. Which leads to a different cruise control set up.
Some guys wouldn't even consider an 840.
As far as collectability everyone seems to be in awe of the V12. 0nly 7-8 thousand V8s, all the rest are V12s.
In my opinion, a Euro 840 Sport individual with a 6 speed would be the coolest unless you are talking CSI, Alpine, and other rare tuner cars.

[8eights]

Most are scarred of the V12 even though it is extremely reliable. It also can handle lots of abuse, Bullet proof in a sense, If you can get any E31 in decent condition, I'd say get one before the price gets crazy. Fwiw, I would of been happy with which ever one landed in my lap but my second one would had definately been a V12

[Budget M3]

In a side by side comparison of E31 840ci vs. 850ci with all else (i.e., color, condition, mileage, etc.) being equal, which model would typically be:

1. More reliable, especially as a daily driver?

2. Cheaper to maintain?

3. More valuable in an open market?

1. Equal: 850 has more batteries and distributors; 840 has more internal moving parts, more complex transmission
2. Equal: no e31 is cheap to maintain
3. Equal: v12 will always have more "mystique" but fewer 840's were made; classic car buyers value both of these traits. That said, BMW will likely never again make a v12 coupe, so my money's on the 850.

[toomanyparts]

The V8 is for the unwashed. Get the V12 and put 315s on the rear and youtube it. Bruh.

[alex840]

A well maintained 840 or 850 are reliable, like any other well maintained car. FYI I have both....

With that hat being said the only thing that bothers me is when v12 goes to limp mode. It is very easily diagnosed and repairable but more of an annoyance if anything.

Never had an issue with 840ci leaving me stranded except my rear end falling off after an upgrade. 840ci is a very reasonable daily driver and has made it from San Francisco to San Diego many times, Tahoe, and with 3:64 rear end a hooooot to drive on switch backs.

In a side by side comparison of E31 840ci vs. 850ci with all else (i.e., color, condition, mileage, etc.) being equal, which model would typically be:

1. More reliable, especially as a daily driver?

2. Cheaper to maintain?

3. More valuable in an open market?

[XAlt]

The V12 is pretty bulletproof and easy to work on, just don't overheat.

[PabloRock]

This seems to be a question that pops up quite often. As a v12 owner, I of course prefer the 12. As far as maintenance, I have no experience with the 8, but my 12 has been very reliable over my 17 years of ownership. It was my daily for the first 2 years, but after that, just a summer driver. Since then, only a handful of issues have come up, that were all sorted out using this board. Aside from regular maintenance, I probably only put another $2k (if that) into the car to fix assorted issues that popped up. But keep in mind it is an old car, and as a daily, you are going to run into issues. And if you don’t wrench it yourself, it will be a pricey endeavor. I’m no mechanic, but so far I have not run into an issue that I haven’t been able to do myself (with help from the e31 community of course).

As far as value, I would think the v12 would be worth more than the 8. Not because of performance, rarity or reliable, but just because people seem to think it’s cooler. I get the "it's a v12?" all the time and they all want to see it. Just because of that, I think a 12 will be more desirable than the 8 down the road.

[TxGR8White]

1. Equal: 850 has more batteries and distributors...

Both cars have the same number of batteries - 2.

[dragon850]

OBD1 V12 Hands down... much more room for upgrades and bullet proof unless overheated.

[mbarrett635]

This car is OBD-2 and was upgraded. It is the holy grail of M73 850 automatics.

Attachment 612541

As a fellow M73 850 owner, I'm curious -- what upgrade(s) have you done?

Mike Barrett

[mbarrett635]

The blue car in the picture is CD05(347) (324) something like that. I do not own it. It is a Dinan twin turbo with Dinan suspension. Dinan exhaust, etc.

CD05001 has the following: Reflashed computer (no 160MPH limiter, more aggressive mapping), camber plates, euro m-sport springs, csi sway bars, revalved Bilsteins, polished intake ports, internally polished intake manifolds, air boxes slightly modded so all air goes to air filters. It came with what are called baby Brembos. All flexible brake lines are stainless steel. It came with servotronic steering (turns down power steering with speed).

This is a pic of CD05347 's engine bay.

Attachment 612561

Very nice. Who/where did you get your computer reflashed? I was always under the impression no one did that for the M73 cars -- I'd love to have that done.

Mine (CD05058) has camber plates, CSi springs, GregK sway bars, a Strong-Strut strut brace, and stock EDC dampers. It handles like its on rails. Mine also came with the baby Brembos and servotronic steering. I haven't done any mods to the engine.

I've also added the extended wood (on the doors, the lower dash and center console like the CSi cars), but in the matching birds-eye maple, along with the matching shift knob. To my knowledge, there isn't another car in the US with the extended birds-eye maple. There might be a CSi with it, if it was special ordered, but the only one I ever saw like that was the wrecked one from which I obtained the drivers side pieces.

Mike Barrett

[dragon850]

Very nice. Who/where did you get your computer reflashed? I was always under the impression no one did that for the M73 cars -- I'd love to have that done.

Mine (CD05058) has camber plates, CSi springs, GregK sway bars, a Strong-Strut strut brace, and stock EDC dampers. It handles like its on rails. Mine also came with the baby Brembos and servotronic steering. I haven't done any mods to the engine.

I've also added the extended wood (on the doors, the lower dash and center console like the CSi cars), but in the matching birds-eye maple, along with the matching shift knob. To my knowledge, there isn't another car in the US with the extended birds-eye maple. There might be a CSi with it, if it was special ordered, but the only one I ever saw like that was the wrecked one from which I obtained the drivers side pieces.

Mike Barrett

If you want the car to be quicker you need a differential upgrade, makes a huge difference on M73 cars.

[rjbaren]

I think that wood interior treatment is just beautiful. I would love to have the wood on the doors and lower dash. Your car is a real prize.

[dragon850]

Breaks away 1 tire that is
You will not loose top speed unless you routinely travel over 160mph. Fuel economy decrease is very very minor.
Have done several on M73 8s and man... what a difference. Night and day through the entire range.

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[dragon850]

TOO late we caught your (p)ullet mis-spelling and we're keeping it.

Hehehehe damn it

[dragon850]

Both tires break. And I know for sure and I'm not going to go take pics of the marks on the street to show you.

Suffice to say the limiter is not active.

With open diff it's difficult to get both tires spinning, usually you do a single wheel burn out.

[JDP530]

My old BMWs have LSDs that I installed myself. When rear wheels are off the ground you can rotate one side and the other side with rotate in same direction. If I am not mistaken, wheels with an open diff will rotate in opposite directions.

[dragon850]

My old BMWs have LSDs that I installed myself. When rear wheels are off the ground you can rotate one side and the other side with rotate in same direction. If I am not mistaken, wheels with an open diff will rotate in opposite directions.

Yes that is correct.

- - - Updated - - -

I have not changed the diff but the previous owner most likely put in a 2.93:1. Hence why both tires break. But I say it has a 2.81:1 because I didn't. The fact that both tires break leads me to believe so.

The 2.93 is not an LSD differential, it's still open (for US market cars). you may actually already have the 3.15 LSD installed who knows, lift the rear of the car up and see if wheels spin in the same direction and see if you could stop I wheel from spinning while the other one is still spinning. There is also a metal ID tag telling you what the ratio is for the diff the S in front of the number on the tag identifies an LSD.
The best possible ratio for M73 cars is 3.45LSD from my experience it's just awesome.

[Torston]

http://www.ebay.ca/itm/1995-BMW-8-Se...wAAOSwaZdZ2trq

Here's a low mile 840ci if anybody interested. I think even his buy it now is too low.

[adwebinc]

http://www.ebay.ca/itm/1995-BMW-8-Se...wAAOSwaZdZ2trq

Here's a low mile 840ci if anybody interested. I think even his buy it now is too low.

Wow... that is great mileage. Man, if I hadn’t just picked up a B7. And if I didn’t have 4 BMWs already... and if my wife would let me have just ONE more.


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[clubE31]

reliability:
- mechanically (840 and 850.....if maintained), really good (try to find a post on engine or gearbox rebuild......almost none)
- electrical: 90% of the problems and not that reliable and complicated to diagnose (just read the forum, ton's of posts)

Cheaper maintenance: 840 but not that much cheaper !

Value: go V12 or V8 manual

BUT all nice: these cars are complicated and expensive and driven daily it is NOT a cheap car to drive (everthing is EXPENSIVE on these cars, at introduction, years later and now it is a BMW classic... so twice as expensive).