M73 V12 in an E39 ? Anyone?

[kchilaka]

Has anyone swapped a V12 M73 Engine (5.4L) from the E38 7 Series into a E39 5 series. I searched google for such an engine swap but came up empty handed. The reason I was wondering about this swap is the following: 1. The E39 5-Series shares the M62 V8 Engine with the E38 7 series so there is a good chance that the E38 and E39 have similar engine mounts, work with the same auto transmission, have the same ECU (perhaps programmed differently), use the same accessories etc etc. 2. The M73 V12 Engine (5.4l) is an option on the 7 series (750il in the US and 750i /750il in Europe) so there is a chance that this engine (from an E38) might just be a drop-in replacement for the V8 in the E39 5-Series. 3. Discarded M73 V12 Engines seem to be very inexpensive from the Junk yard so instead of fixing a broken V8 Engine in an E39, swapping a V12 engine into a 5-series seems like a delicious proposition. 4. Why not a Turbo/Supercharger? Well, if you start with an E39 that has an engine that needs to be replaced, you cant turbo/SC it and have to get a new engine. If you have to get one anyway, why not a V12 Anyone have any thoughts/information/links on this topic?

[brahtw8]

There were a few E34 550is created.

I found this 2004 email from Brett Anderson of Koala Motorsport:

This car [E34 550i] was built by PTG circa 1990. There was a magazine article on it at the time that I have around here somewhere.

It was built as an automatic, and PTG said they'd "never do that job again".

I don't know it's ownership history until recently, when Steve Castle of
Atlanta bought it off of eBay. He immediately had it converted to a 6spd.

A year or so later, he sold it, presumably to the current owner. The engine
failed, owner took it to Leo, it had burnt exhaust valves. Badly burnt.
Leo sent me pictures.

Leo rebuild the motor, check with him to find out exactly what was done.

Oh, and the owner is incorrect in his auction text, it's not the only one in
the world. I have an 850CSi 5.6V12 and 6spd in an E34 M5, in the shop,
getting it's final touches.
;-)

Brett Anderson
KMS

Also here:

http://forums.bimmerforums.com/forum...highlight=550i

http://www.bimmerfest.com/forums/showthread.php?t=54301

http://www.m5board.com/vbulletin/showthread.php?t=39701

[kchilaka]

Holy crap.. V12 6 Speed huh.. Must be a mad ride.. Did read the other links: it is true that the V12 did not make too much more power...maybe thats why the majority of people prefer to go SC/Turbo.. But then, V12s are V12s .. kinda special .. God knows how much power one of those V12 engines can make if they have get the Original BMW M1 heads . One for each bank of cylinders...

[Hotswimmer]

Everything I've heard about the V12 is that it is hugely trouble-prone. Apparently, it was basically two of the in-line 6-cylinder engines kluged together, not a new, ground-up V-12 design.

[nightkrawler]

you wouldn't be happy with the v12 in your car, they were designed to be high speed autobahn rockets.. not really much power down low. and as said, they are problematic. there are 2 dme's in the car to control the engine, when one goes bad both have to be replaced and they are very $$$$.

[xatlas0]

Considering the M62TU makes almost the exact same hp/tq, there isn't much point to the swap. Plus, as already stated, the M70 is problematic.