BMW V-12 1995 M-73

What engine are you torturing? Is it inside some car?
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bill
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BMW V-12 1995 M-73

Post by bill »

Hello All,

I have just purchased a BMW V-12 from LKQ junkyard. Condition unknown.

I will run a leak down test to see what it needs to have done.
Wanted to get it running ! It needs spark and fuel . I am open to suggestions! Have no preconditions .
Would like to leave open the option of turbocharging at a later date. Also, I can raid the junkyard for Fuel injection and ignition parts .
GM coil on spark? VAG throttle body? BMW throttle body?

Thanks!

bill
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Re: BMW V-12 1995 M-73

Post by AndreyB »

VAG ETBs are the ones we are most comfortable with please go with VAG even while probably same Bosch as many other vehicles.

Do you plan to have some engine stand or wooden crate while you are working on it? As it it's unclear what you have and what you do not have. Please mount it and write what you have and what you do not have. What is your plan for coolant system - inside the car or outside the car?
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Re: BMW V-12 1995 M-73

Post by AndreyB »

Let's take two steps back: what is your long term goal with this M73?
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Re: BMW V-12 1995 M-73

Post by bill »

yes, i will mount it on an engine stand.

I would like to make the V-12 a runner,
and then stick it in a future project car.

Making it workable is mainly
1-- assessing the leak down ( rings and valves) , bearings, timing chain, gaskets, headgasket, water pump, etc --- and bringing them up to snuff.

2-- getting the Fuel injection/ spark going... so it runs.
the option i would like is a single ECU running all 12 cylinders, and spark. Preferably that will accept some turbo boost also. (someday)
Nobody seems to make anything above 8 cylinders. So...
The most likely option is TWO ECU's like BMW had set up originally. But NOT a BMW unit. Somebody else.

3-- getting a manual transmission / clutch going. That will probably be the hardest part. Maybe a BMW? Or chevy or ford tremec with custom adapter plate? not sure yet. The Flywheel, Clutch and pressure plate from a V-8 BMW will fit on the V-12, but not the transmission. https://www.drifthq.com/products/pmc-motorsport-adapter-plate-bmw-v12-m70-m73-s70-bmw-m20-m50-f0m50-m7?variant=11639646355503 https://transmissionadapters.com/collections/bmw/products/bmw-v12-to-manual-trans

4-- put into a car and tear around

5-- maybe turbo someday.

Thanks !!

bill

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Re: BMW V-12 1995 M-73

Post by AndreyB »

We have a proven https://github.com/mck1117/proteus board by @mck1117 which is supposed to run M73 by itself and I have two of these boards.

At some point I will finally run my M73 on my proteus. As we speak work is happening on making proteus a bit more mass-productionable. I will probably run my M73 on my proteus before you have coolant in your M73.

Funny options are for me to sell you one of my proteus boards with a proven M73 harness or an even funnier option would be for me to sell you my whole M73 setup since technically I do not really need it and one day I would like to switch to N73.
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Re: BMW V-12 1995 M-73

Post by OrchardPerformance »

Hi Bill.

Unless the engine has been abused then you will probably find that mechanically it is pretty solid. They are very tough engines and the rings/bores are long lived.

Rod bearings are normally the first things to show wear, they are cheap and easy to change but you will need rod bolts, rod bolts are shared with the other engines but are either 53mm or 47mm long, be sure to get the right ones.
The bearing shells are listed as unique to the M73, however I was damn sure that the rods are the same between the M73 and the later M52 engines Thus the rod shells from the M52 should also be the same.
This is not the first time I have seen weirdness of this kind, it often comes down to one part having an extra surface coating or QA process applied, things that don't matter to the home/race engine builder.

Head gaskets can go, they have the same issue as the M20 of leaking out external to the block, how bad this is and if you can live with it is up to you, normally pretty good for sealing internal to the engine though (water to oil/bores).
If you decide the gaskets need doing then change the plastic cam chain tensioners while you are in there and give the hydraulic tensioner cylinder a strip and rebuild.

Cam journals will look like someone has used an angle grinder on them, that means they are "normal", I have seen BMw engines of this generation with scored cam journals after less than 25k, they just go like that but keep running fine.

You will find this invaluable for parts - http://bmwfans.info/parts-catalog/

Manual transmissions are a problem.
The best solution I have seen is the kits from eastern europe that allow a 6 cylinder gearbox to be used. There are some 6 cylinder boxes that will handle the torque of a turbo M73, especially the 5 series diesel box.
https://pmcmotorsport.eu/product-eng-836--PMC-Motorsport-Gearbox-adapter-plate-BMW-V12-M70-M73-BMW-M57N-M57N2-GS6-53DZ.html
They also offer flywheels but do not seem to list them with a price at the moment.
Previously they were about €1000 for the kit which when you see the cost of an 850CSI manual flywheel, clutch and an gearbox might seem like a good deal.

It is always possible to convert a manual box by hacking off the bell housing and welding it to a 6 cylinder box as well.

Turbo charge it and you can expect turbo LS numbers. A stock engine at 7psi will break the 600hp mark.

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Re: BMW V-12 1995 M-73

Post by bill »

Hello Andrey,

At some point I will finally run my M73 on my proteus. As we speak work is happening on making proteus a bit more mass-productionable. I will probably run my M73 on my proteus before you have coolant in your M73.


I am sure you are right! I am juggling lots fo stuff right now...

Funny options are for me to sell you one of my proteus boards with a proven M73 harness or an even funnier option would be for me to sell you my whole M73 setup since technically I do not really need it and one day I would like to switch to N73.

How much is a proteus board cost? and how much for the whole M73 setup?

On another note, i have been following your reverse engineering of the Ionic Ignition-- of the SAAB. I was the one ( Hank the Fourth) who posted the original question on Speeduino-- https://speeduino.com/forum/viewtopic.php?f=12&t=2332
Your posts and Youtube clips are super interesting.

Have you done anything further with Ionic Sensing? Is Rusefi compatible with Ionic sensing?
Apparently some of the newer BMW's are also using it.

Another note: Copart had a BMW 760 for sale up in boston. Sold for $300 plus copart fees. a couple months ago.
Keep an eye out if you want a V-12 with direct injection.

https://www.salvagereseller.com/vehicles/history/type/car/make/BMW/model/760_LI
Price History
Make / Model Year Title Type Primary Dmg Millage Bid Sale Date
BMW 760 LI 2010 SC - SALVAGE CERTIFICATE Front End 127,869 $4,000 USD Mar 17, 2020
BMW 760 LI 2004 ST - SALVAGE TITLE Front End 66,886 $150 USD Feb 19, 2020
BMW 760 LI 2006 SC - SALVAGE CERTIFICATE Front End 186,962 $625 USD Feb 14, 2020
BMW 760 LI 2007 SC - SALVAGE CERTIFICATE Burn 0 $200 USD Feb 13, 2020
BMW 760 LI 2004 SC - SALVAGE CERTIFICATE Undercarriage 210,698 $90 USD Feb 3, 2020
BMW 760 LI 2004 ST - SALVAGE TITLE Rear End 0 $1,100 USD Jan 28, 2020
BMW 760 LI 2006 SV - SALVAGE VEHICLE TITLE Side 75,928 $3,200 USD Jan 16, 2020
BMW 760 LI 2004 CQ - DLR/DIS/EXP - CT OTHERS Mechanical 97,285 $2,400 USD Jan 14, 2020
BMW 760 LI 2003 CZ - DEALER ONLY CLEAN TITLE Minor Dent/scratches 130,748 $1,500 USD Dec 30, 2019
BMW 760 LI 2006 SC - SALVAGE CERTIFICATE Side 104,322 $950 USD Dec 11, 2019
BMW 760 LI 2004 CT - CLEAN TITLE Mechanical 51,823 $4,500 USD Dec 5, 2019
BMW 760 LI 2006 CT - CLEAN TITLE Normal Wear 127,359 $1,600 USD Dec 4, 2019
BMW 760 LI 2013 FV - FLOOD SALVAGE VEHICLE TITLE Water/flood 82,102 $8,900 USD Dec 3, 2019
BMW 760 LI 2010 ST - SALVAGE TITLE Mechanical 95,499 $3,250 USD Dec 2, 2019
BMW 760 LI 2006 SC - SALVAGE CERTIFICATE Vandalism 134,182 $400 USD Nov 1, 2019
BMW 760 LI 2003 CQ - DLR/DIS/EXP - CT OTHERS Mechanical 141,688 $250 USD Oct 17, 2019
BMW 760 LI 2006 ST - SALVAGE TITLE Front End 117,812 $1,450 USD Oct 8, 2019
BMW 760 LI 2006 CT - CLEAN TITLE Mechanical 134,186 $250 USD Oct 7, 2019
BMW 760 LI 2010 ST - SALVAGE TITLE Minor Dent/scratches 82,242 $11,000 USD Sep 30, 2019
BMW 760 LI 2003 CT - CLEAN TITLE Minor Dent/scratches 138,365 $650 USD Sep 16, 2019
BMW 760 LI 2003 CT - CLEAN TITLE Normal Wear 152,588 $1,850 USD Sep 5, 2019
BMW 760 LI 2014 SC - SALVAGE CERTIFICATE Front End 103,502 $5,000 USD Aug 23, 2019
BMW 760 LI 2006 SC - SALVAGE CERTIFICATE Vandalism 89,933 $3,100 USD Aug 19, 2019
BMW 760 LI 2004 CQ - DLR/DIS/EXP - CT OTHERS Mechanical 0 $350 USD Aug 15, 2019
BMW 760 LI 2003 SC - SALVAGE CERTIFICATE Front End 141,284 $800 USD Aug 6, 2019
BMW 760 LI 2006 SC - SALVAGE CERTIFICATE Normal Wear 0 $850 USD Aug 1, 2019
BMW 760 LI 2003 CT - CLEAN TITLE Front End 0 $600 USD Jul 1, 2019

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Re: BMW V-12 1995 M-73

Post by bill »

Hello OrchardPerformance,

Thanks for the notes! Those will come in good use soon.

The Tranny will be the biggest problem. BMW manual transmissions are extremely rare around these parts. Especially a diesel model. I will probably end up with a Chevy or Ford Truck tranny. something that can handle the torque.

I did buy a present for the engine... some twin turbos off the N54 engine--

they have the same 91mm bore spacing, so should work with a bit of work
this should take care of the right side...

now i just need another set of 2 turbos for the left bank of the V-12
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Re: BMW V-12 1995 M-73

Post by stefanst »

bill wrote:
Tue Mar 31, 2020 6:39 pm
[...] now i just need another set of 2 turbos for the left bank of the V-12 [...]
Double-twins? I'm listening.....

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Re: BMW V-12 1995 M-73

Post by bill »

The BMW N54 engine has 91mm bore spacing. and Two turbos. for the straight six.
So i grabbed the twin turbo setup off of one N54, and that should fit the M73 left bank.
Just have to wait for another 535i to appear in the junkyard, and i can do the M73 right bank

Of course i have to pipe the oil and coolant to the turbos, but the install on the manifolds / head should be pretty straightforward.
Will have more updates next week on that.

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Re: BMW V-12 1995 M-73

Post by bill »

Looks like the turbos will fit okay . if they are turned up, not down (Since the starter is in the way).
need to fabricate an adapter plate, since the exhaust manifold bolt pattern is different, but that is not hard.

that is all the news for today...
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Re: BMW V-12 1995 M-73

Post by AndreyB »

Engine stand? Crank button & cranking power? Coolant? :)
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Re: BMW V-12 1995 M-73

Post by bill »

its on the stand now
should be cranking over tomorrow

more news to come soon
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Re: BMW V-12 1995 M-73

Post by bill »

Ordered the Proteus board.
hope to bring some fire to this monster soon

!!!
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Re: BMW V-12 1995 M-73

Post by AndreyB »

Bill I see a lot of stuff missing between ECU and wroom wroom :)

Show us your coils and your throttle bodies :)
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Re: BMW V-12 1995 M-73

Post by mck1117 »

bill wrote:
Sat May 23, 2020 6:04 pm
Ordered the Proteus board.
Your board is in the mail! I'll PM a tracking number.

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Re: BMW V-12 1995 M-73

Post by bill »

mck1117 wrote:
Sat May 23, 2020 10:18 pm
bill wrote:
Sat May 23, 2020 6:04 pm
Ordered the Proteus board.
Your board is in the mail! I'll PM a tracking number.
THANKS!!!

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