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A quick teaser


Guest 240zoom

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Guest 240zoom

Yeah, twin turbo 5 litre v12 is filling me with trepidation (especially when putting my foot into it in a 2300lb car), but I'm sure the ooooh-aaaah factor will be worth it.

 

I'm struggling with the oilpan issue still. Haven't decided if I'm going to go with a dry-sump system or rework the front cross-member and steering rack...

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What transmission are you using? Are you going with the stock BMW unit? I'm starting to gather parts for my own V12 swap and I havn't a clue what to use for a trans! I can make an adapter plate or bellhousing if I have to. I'd love to hear any recommendations you have. Thanks.

 

edit: Just curious, but have you had the pan off to take a look in there?

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Guest 240zoom

Hi Chewievette,

 

I was originally going to go with a T-5 transmission (this was before the twin turbos entered the picture). Depending on the year of car it comes from (Ford's got the best range) the tranny can handle approx 300 lb-ft of torque. Just borderline for the stock V12 (Mine's a '92, so it should be about 340 lb-ft in stock form).

 

Obviously the turbos have forced me to re-think the transmission. I'm now going to use a T-56. Again, depending on the model, it should be good up to 600 hp/ 650 lb-ft of torque.

 

I'd have loved to use Audi's new 6-speed clutchless manual tranny, but mega-bucks ...

 

Soooo ... To use the T-56, I'll be making an adapter plate so the tranny will bolt up to the engine. I'm still researching the clutch and flywheel set up (which flywheel to use - you wouldn't happen to know if any other model BMW engine flywheels bolt up, would you?).

 

I haven't had the pan off the engine, but I've got the BMW shop software, so am pretty familiar with the internal workings of the engine after going over the blue prints. There's a pretty serious oiling system in there ...

 

I'd love to swap any information that we might have.

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I just started researching this motor last sunday so I cant imagine I'd be of much help. and from what I'm hearing this will be the most advanced engine I've ever worked on! I mean I've done work on turbines and large recips but this thing takes complex to a whole new level! I'd love to get my hands on the shop manual like you have, where did you get it and how much did it cost? So far I've been on a best guess basis and with an engine this complex, that's probably not a good thing.

 

I was looking at transmissions today and trying to find something suitable, the one that strikes me as best right now is the T56 but I read that a lot of people dont like the shift feel and a couple of other gripes about it. But I do think it needs a six speed, I mean if your doing V12 that just screams european sports car and there just isn't any else for a sports car than a six speed. I'll probably end up with the T56 also, at least for starters.

 

I'm sure we can dig up a flywheel that will work, its just trying to find the right one... Like I've been saying all along though, I cant know for sure until I get some parts to look at!

 

If this deal works out, I'll be getting a 1989 750il engine. Unfortunately it needs a rebuild so I'm trying to find a rebuild kit. My local BMW guys aren't being too friendly about it, so I need to find another source. Do you know where I can find one? My next stop is my friend at the local rod shop, maybe BMW would be more willing to sell to a business?

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Guest 240zoom

I haven't had much luck with BMW either - they don't seem to want to encourage the DIY crowd.

 

I have heard (but not confirmed) that the M70 (our V12) has a lot of interchangeable parts with the M20. The M70 is essentially two of these engines sharing a common crankshaft. BMW did some good engineering with this engine (a massive understatement) in that you could take the left-side head and bolt it right on to the right-side, etc. A common upgrade is to take the 4-valve-per-cyl heads off a new V12 and bolt them on.

 

The downside to the V12 is that the cylinder sleeves are aluminum, and don't use steel inserts. This adds substantial $ to the cost of a rebuild. One other route is to have a competent machine shop insert steel sleeves (I've run into someone who's had that done a year ago, but no idea what was involved).

 

I've found a company on the web that makes custom light-weight aluminum flywheels for our engine, but not sure of the cost. A similar replacement BMW flywheel runs about $400 CAD. Still investigating.

 

What are you doing for spark and fuel management? The stock BMW's use 3 (yes, 3!) ECMs to control all that stuff. Personally, I'm not going to mess with it (hard to get info from BMW, again) and will be running dual Megasquirts with dual MSNS for spark (or the new MSII when it's out).

 

If you really want to get the best shop manual (and pretty well the only one) you should buy the Bently manual for a 750/850. They're pricey (around $100+) but well worth it. Quite often you can find them on EBay in CD form http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=34211&item=7941588696&rd=1

 

I'll be setting up a build diary online with photos and notes soon, and will be happy to post the link once it's up.

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Well my main concern right now is getting the motor here. I'm buying from a guy in Oklahoma and Fedex is charging some outrageus amount so I'm trying to get a couple of buddys and get a road trip going. We'll see how that goes...

 

I'm going to decide on the ignition and fuel management when I'm doing the rebuild, but I want to backdate the management and use as much mechanical control as I can. I'd really love to run six two barrel carbs on this sucker! Look sweet wouldn't it? It shouldn't be too hard, I dont really see why. But I'm thinking that I'll have to use some sort of electronic ignition because I'd rather not try and adapt a distibutor system! This things going to be a Major headache! ...I cant wait!! I just have to keep reminding myself ...V12 ZX, V12 ZX...

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Guest 240zoom

V12 ZX, V12 ZX... damn that has a nice ring to it, don't it?

 

The V12 has two ignition systems ... one is the electronic system, and there's the fail-over system, which is actually distributor based. When everything's fine, the engine is controlled by the ECMs. If those fail, the engine goes into limp-home mode and uses the distributors exclusively.

 

If you look at the pic in my post, you'll see two dish-shaped plastic caps on the end of the heads. Below those are 6-post distributors that are driven by the cam shafts. I'm not sure, but I don't see why you couldn't use those to drive the spark (you'd have to check out how to control the advance).

 

6 carbs on that beast would sound nasty and look nastier :)

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Yeah, my idea for the six carbs is use the stock intake flanges and about 2in of the tubes then new flanges and mount the carbs to the stubs! Six Dual Cross Ram Carbs!! I'm getting anxious just thinking about it!

 

Ah, I'll just get it then strip off everything I dont like! It'll run just fine!! ;)

I'm sure I'll figure it out. It might take a while but with our combined efforts and lots of time tinkering it'll work.

 

Distributors eh? ...like this?

http://album.hybridz.org/data/502/8657bmwV12.jpg

(Pic is from dot)

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Guest 240zoom

Those dizzies are exactly right. They hide under the plastic covers. That's a purdy engine.

 

If you like, I could take a peek under the caps and see if there's any set up for advancing/retarding the timing.

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http://www.lambolounge.com/Chassis/Engine/BMW-V12/BMW.asp

 

Check out the last engine on this page, its has adapters to use chevy six distributors. Looks pretty sweet, I dont know how much room there will be for a setup like this, but still its most definately possible! It looks like all he used of the original distributors is the input shaft from the engine. Its really a pretty sweet setup. I like his intake too, looks awesome! Maybe this site can give you some ideas.

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Guest 240zoom
Looks pretty sweet, I dont know how much room there will be for a setup like this, but still its most definately possible!

 

engine.jpg

 

Chewievette,

As you can see, there's plenty of room before running into the radiator core support. The engine can also be set back another 2" or so too, depending on what tranny/adapter I come up with.

 

Ferd/289,

I agree, for ETs and acceleration, it's hard to beat an auto ... but damn, rowing through 6 gears with a snarling V12 in a 240 just has too much sex appeal!

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damn, rowing through 6 gears with a snarling V12 in a 240 just has too much sex appeal!

 

Amen brother!

 

 

If there is no mechanical advance on the distributor there are always other solutions. I used an Accel programmable timing control on the Jag. This product doesn't appear to be available anymore but there must be others out there. Chewievette six Webbers pushing through the hood would be nice. Fuel ejection is fairly simple once you get into it.

 

This swap is starting to look very appealing.

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  • 3 weeks later...

Gee, finding one of these engines is hard work!! When I started looking at this swap I had two that I was looking at but when I found out that shipping for them would be more than the engine itself, I started looking local. The closest one so far is a 3hr drive!! Now if only it'll warm up a bit I can hit up all the junk yards looking for one. but me knowing how I am, I'll probably end up just running around all day in the freezing weather because I'm too anxious to wait! I'm starting to think that rebuilding the motor is going to take as long as rebuilding the car ...which now that I think about it should work out perfectly. Interesting how that works isn't it? So the whole point of this post is to one, vent a bit, and I did so I feel better now... and Two because if you know where one of these engines is located ANYWHERE near West Michigan, PLEASE let me know, I'll chase any leads you can send my way! Thanks.

 

Btw: How's the car coming 240zoom? Any progress?

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Guest 240zoom

The availability of these engines seem to come in spurts. I actually found mine by using http://www.car-parts.com (search for '92 750 or 850). Ebay is too pricey for these it seems.

 

It only cost me $150 CAD to have the engine shipped freight from Ontario to BC (about 2500 miles).

 

I have made some progress, but not a lot that can be shown. I've ordered all the electronics that I'll need to assemble the fuel and spark management computers. I've also decided to with a dry-sump system so have been planning that for the engine. I'll be removing the stock oil pump and replacing the lower oil pan with a much slimmer pan that the dry sump pump with scavenge. I'll post some pics once I've got something set up.

 

(I've also purchased a 22,300 BTU kerosene heater for the shop 'cause, damn!, it's just too cold to work in there right now).

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  • 4 weeks later...
  • 2 weeks later...
...A common upgrade is to take the 4-valve-per-cyl heads off a new V12 and bolt them on....

 

240zoom,

 

Your BMW engine looks really clean!!! I sure hope to see it run someday. Despite being 2-v-per-cyl, with that twin turbo it is virtually a McLaren F1 engine!

 

I got interested in the BMW V12 swap(don't have enough money/time/space at this moment, but a bit knowledge can't hurt) and I did some research on this website and on others. I've come up with some questions :

 

Is it possible to use 2 BMW dohc straight 6 cylinder heads on the old v12?

 

Can the old V12 be bored out to bigger displacements? (5.0 -> 5.6 or more?)

 

How much did your engine cost? (I live in BC too, hence whatever cost it is, could apply to me as well)

 

Why is it that many of the old BMW V12 in the wreck yard are "burnt"?

 

Can a "burnt" engine be fixed to work again?

 

 

Thanks a lot

TheNeedForZ

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