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V12 vs V8


Chewievette

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Well, I've been thinking again...

I recently stumbled upon a rather good deal for a BMW 5.0L V12 out of a 1992 850i Problem is that I have to buy very soon or it'll be gone. I need to know how big of a hole will I be digging for myself if I buy this motor? I realize that Parts are expensive, to say the least, and I'll have to resort to fabricating everything. My other option is to buy the sbc I was originally planning on and drop that in. Both are about the same price(initial cost) so that's not a problem. I guess what I'm asking is, is it worth it? I'm building this car as my weekend beater/show car, so power isn't really a deciding factor. I really want the V12 simply for the WOW factor at the shows, but a good reliable V8 is always a good thing. I did some searching on the site and saw a few people doing this swap but no one had it running yet. and nothing very recent (most BMW V12 threads came up as dead links, old server?) I know that I'm the one thats going to be making this decision, but I'd just like to get some input before I dive in head first. All input is welcome.

Thanks.

 

Btw: My car is a 1979 280ZX.

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I've been flipping through my repair manual and looking at the pictures to see what kind of clearance I'd have and I noticed that the ZX has a crossmember that's set twards the rear of the car and that the steering rack is behind the crossmember. I'm not familiar with the early Zs but I seem to recall this being a huge sticking point of this swap. It looks to me like the crossmember is directly in the middle of the engine, and if I'm not mistaken this is where it is on the BMW as well. assuming that my straight six and the v12 are approximately the same length then I will have minimal fit issues, correct? Does anyone have a picture of the early z's underside that shows where the front crossmember is?

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We have one V12 guy here goes by DOT. He has a Jag 12 in his S30. I know this is not a BMW and not an S130 but his is a finished running car. He could have some valuable advice.

 

To say fitment issues would not be a problem is a huge assumption. As an example just look at Auxilary's rotory swap. Small motor, big engine bay, and he still has to notch a frame rail to get it to fit.

 

Initial motor cost is a small percentage of the swap cost. A safe rough gauge of the price of a V8 swap is to figure out what you think it will cost and them double it. If you decide to go V12 I would say quadruple that number.

 

I'm not trying to discourage you, I'd love to see it. Just go in with your eyes wide open. You don't want to get half way through and give up after spending a ton of money.

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I contacted dot and we are in the process of trading PMs, I also contacted 240zoom who is doing the BMW V12 S30 swap.

 

I'm not saying that fitment wont be a problem but it seems that everyone is worried about the oilpan, so I wanted to point out how I want to get around that. To be sure I'd have to have both the car and the motor in the same place at the same time.

 

If I do decide to go with the v12, I'm going all out. I'm not going to worry about the cost, it'll either cost four times more all at once or cost the same four times longer. I'm going to take my time and do it right, giving up is not an option.

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When I was searching last night I read that an option might be turning the oil pan around, but I hadn't read anything else about it. well I just found this picture of the bottom of the block and from what I can tell it looks like it was designed to do that. What do you think?

 

http://img.photobucket.com/albums/v11/chewievette/Cars/bmwpan.jpg

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showphoto.php?photo=780

I don’t know about the swapping the pan around. It looks like the rear is part of a bell housing support.

Chelle had said she used a dry sump oiling system as used on the MacLaren. The system cost about a grand.

 

I would be tempted to make a sandwich plate with a sump on the rear. It depends on the internal oil lines.

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http://album.hybridz.org/showphoto.php?photo=780

I don’t know about the swapping the pan around. It looks like the rear is part of a bell housing support.

Chelle had said she used a dry sump oiling system as used on the MacLaren. The system cost about a grand.

 

I would be tempted to make a sandwich plate with a sump on the rear. It depends on the internal oil lines.

Oh man! That is exactly what I want to do someday :twisted:

Just gotta find a donor car.

 

Dan

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I've been doing some more research and thinking and I'm basically sold on the idea of doing this swap! I need to sneak a peak at a first gen to compare crossmembers, but from the pics that Glenn sent me (Thanks!) It looks that the 2nd gen's crossmember is almost entirely behind where the first gen cross member is! Which is rather encouraging. but as I said before I wont know for sure until I get both the car and engine in the same place! If anyone has the motor out of their 1st gen, I could use a couple of measurements, please PM me. I guess I'm going to bite the bullet and pick up the V12.

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Thanks for the help and encouragement guys, I'm sure going to need it! Thanks for the pics Tim! I think I can use some of that.

 

Edit1:

This is the new V12 but I assume the pan is similar...

http://img.photobucket.com/albums/v11/chewievette/Cars/123-3.jpg

DOH!! I just noticed that the new v12 is rear sump... this pan might bolt up to the older engine ...hmmm. Probably just wishful thinking.

 

and I just like this pic:

http://img.photobucket.com/albums/v11/chewievette/Cars/album_pic.jpg

 

Edit2:

Wow, this is getting expensive already!! I just found out the shipping is costing more than the motor itself! I think its funny, but oh well. I just want it here!! Not that I can work on it... but it feels good to think I'm getting something done!

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  • 2 months later...

Heya - I was just wondering how the project is coming. Did you do a drysump setup? I was digging around here at home and I have a bunch of pics of the engine setup- I've been playing with the car some lately tearing a few things down so we can repaint it and so my memory is kinda refreshed on all the issues with this swap. To refresh everyone's memory we are running a 1992 BMW V12 with a T-56 six speed. We are running a dry-sump system and this setup is in a 1977 280z chassis with a 250 GTO style body

Chelle

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Well, I havn't made too much progress lately. I located another source for the engine but I havn't been able to get it yet. I've been dealing with a ton of other issues around here including a couple of things on my daily driver acting up. Not to mention its Verrrrry cold right now and I dont have a heated work area, so its difficult to get motivated enough to brave the cold. hopefully I can get a bit further on this project when it warms up.

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Hey Chelle:

I wouldn’t mind seeing some pics on how you put the engine and transmission together and maybe a description on how the fly wheel, clutch and pressure plate issues were handled….

Please and thank you...

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Hiya :)

Engine and trans was easier than ya might expect.

Use a stock BMW manual trans flywheel and pressure plate. The pilot bushing on the BMW is the same size as the T-56! So that requires no adapter. The T-56 we used has a hydrolic throwout bearing so that was "easy" too. Hardest part was the bellhousing. No other BMW uses the same bellhousing, and on the rare 6-speed V-12 the bellhousing is part of the trans. Fortunately the Automatic uses a seperate bellhousing very similar to what we are all used to seeing on RWD manual trans cars.

So, "all you need to do" to bolt a T-56 to one of these engines is use the BMW flywheel and pressure plate and a T-56 with the clutch disk that matches it with the T-56's throwout bearing and couple it all together with a modified BMW bellhousing.

To modify the bellhousing you need to mill off enough off the back to have the length of the input shaft right. It will require you to build up some material as well to make the mounting solid, but it's really not as scary as most assume.

Will post some pics this weekend

Chelle

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Oh and another thing is the dry sump setup is nice and eliminates like 5" of height which HAS to come out. With a drysump these will fit in a stock body z-car, with the stock crossmember. Putting one of these engines in a GTO style car requires additional lowering by either modifying the crossmember or modifying the firewall and setting the engine far enough back to be behind the firewall. There is a lot of room behind the dash to do this if you eliminate the stock heat/ac unit, but not something the typical home builder is going to be willing to try.

The engine is super easy to install a dry sump in - my earlier suggestion of trying to put the pickup at the back with a rear sump mod will NOT work. The oil pump is huge and takes up a large bit of the volume of the front sump and is driven by a chain off the front of the crankshaft. You can't relocate the pump to the back. Once you remove the stock pump there are no holes to plug or anything... you remove the chain and pump and put on a modified pan that's flat and set the engine in. The pressure line from the dry sump goes into the drivers side of the engine where the external filter braided line attaches.

Will post the pics later

Chelle

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Is the pressure plate and flywheel particular to the V12 or will a set up from a six work? Are there any balance weights on the flywheel to be concerned with?

Where is the oil pump now located and how is it driven?

Thanks.

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Glen,

Well I don't know if the flywheel is same as any of the other BMW's but I ordered ours new at the BMW dealer and list price was only just over $300.

There aren't any obvious counterweights.

The Oil pump was driven by a chain and is now mounted on the bottom left side of the engine (external) and driven by a belt.

Here's some images

First one - wow.. looks too big! (but don't worry - it does fit)

BMW_oil.jpg

Here's the massive front sump:

BMW_oila.jpg

And here is why the pan needs to be so huge:

BMW_oilb.jpg

BMW_oilc.jpg

BMW_oild.jpg

With the pump out and tin bottom pan off, there's a lot of wasted space!

BMW_oile.jpg

BMW_oilf.jpg

Here's a dry sump external pump on Jay's Ultima

drysum1.jpg

Here is what he did to modify his oilpan. He sawed off the kicked out sides and made a flat pan.

drysum2.jpg

drysum3.jpg

 

Will get some pics of my pan - we took off quite a bit more of the front of the pan.

Chelle

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Thanks for the pics Chelle. It's nice to finally see the inside of one of these motors to get an idea of what’s going on. The modifications don’t seem to be all that extreme. Nice work on the pan and sump.

I hope your instalation turns out this nice.

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