Unique find

[ross1]

literally it's two M20s smashed together.

Wrong

[ross1]

i had an 1990 750il in black for about 5 years. I bought it in 2002 for $6k in perfect shape with about 90k miles, and that car kicked ass. The reputation for them being lemons is absolutely true though; if you pick it up expect to put money into it every 3-6 months. That being said, no car ive ever owned came close to the joy of driving that car and the comfort of the ridiculous luxury features that come with it, like power reclining rear seats. That car was the ultimate road trip machine. Even with 5 people in it you could 110mph at something ridiculous like 3000 rpm. When you kick it down into sport 1 setting, the whole car would lower and the steering wheel would tighten up for blast off. If i had the money to maintain own, id seriously consider getting another

Yes, they can be great. BUT
They are popular with penniless poseurs, pimps and such who cannot/do not maintain them.
IF maintained they do not break more than other high line complicated cars and will cheerfully and swiftly go 300k miles in grace and comfort.
There ARE more junks than good ones around so buyer beware.

[Streichholzschächtelchen]

Wrong

it is two m20s.

[nando]

Wrong

really?

75mm stroke, 84mm bore? yep.
SOHC, 2v head? yep.
91mm cylinder spacing? yep.
runs on Motronic 1.3? yep.
one Motronic computer per bank of 6? each as if it were an M20? yep.
batch fire? yep
distributor ignition? yep

it may have some differences, but it's pretty obvious that they started with the M20 as a base to build the V12s.

[ross1]

really?

75mm stroke, 84mm bore? yep.
SOHC, 2v head? yep.
91mm cylinder spacing? yep.
runs on Motronic 1.3? yep.
one Motronic computer per bank of 6? each as if it were an M20? yep.
batch fire? yep
distributor ignition? yep

it may have some differences, but it's pretty obvious that they started with the M20 as a base to build the V12s.

Yet they share nothing so at the risk of argueing semantics they are not "literally two M20s", if so the cams would be belt driven and it would be an iron block. Other than bore spacing and bore/stroke dimensions didn't all of BMW's engines of 1988 meet the rest of your criteria?

Bosch didn't have a twelve cylinder system hence the twins.
BMW sold this as redundancy/reliability. I believe the M70 was a clean sheet design with a 5 liter displacement drawing on existing known and good architecture.

[bastianshaw]

what SPECIFICALLY is expensive to fix?

[CrusherCurtis]

What?
The E32 was argueably the finest car of it's day, bar none. It's build quality is better than any since.
Having said this it IS ghastly expensive to repair V12 models which have suffered from deferred maintenance. I know.
When all is right they are magnificent cars. Sadly, once no longer the current hot stuff they typically fell into the hands of those unable or unwilling to maintain them. That any remain running at all under those circumstances is testimony to the original quality.
The cheapo wheels on the OP's example scare me and are indicative of likely "wrong" ownership, as is it's "mate" in that driveway. When new it likely cost more than the home it now sits by.
They are available sometimes for a few hundreds dollars after an owner gets a staggering repair estimate.

LS400 was the best of its day hands down