Yes I guess anythingn has its price.
1998 BMW M3 3.2 Cabrio Alpinwei฿ III on Schwarz German spec 1 of 12
SMG SRA PDC AUC OBC GSM HK UURS IHKA FGR MFL
IG: https://www.instagram.com/iflok/
Wokke...just speechless...absolutely top shelf!!!
I have a question-
I'm basically running some M70 parts on a M73 as well. I saw no mention of how you handled the the difference in the length of the crank 'nose.' The M70 is about 13mm greater in length than the M73. The spacer/large washer is 8mm- leaving a difference of 5mm between the harmonic balancer and the crank. With the torque required to seat the bolt- I think there should be NO void between the two.
I was looking at taking it to my machinist buddy and have him make one 13mm spacer.
How did you handle this?
Richard
M70 on the left- M73 right...Spacer- notice the difference in depth. When mounted on the engine everything lines up-they both seat on the same place on the crank.... BUT the empty space between the crank and harmonic balancer makes me think....
M70
M73
Sorry for my heavily delayed answer. For some reason I wasn't informed via email about your reply.
Anyways:
I had the same headache and went to my machinist asking for a special "washer". But in his opinion it isn't needed. A long enough bolt will do it he said.
So I went ahead and bought 25 bolts of the proper length. I still have 20 in stock So if you need one....
Hello I read through the entire thread and ended up here.
I am doing your 'hybrid' conversion.
Do you mind making a list of the things you had to change? it will make it easier to me and to anyone who wants to do your conversion.
I compliment your eye for the detail. That must be the cleanest engine in the world.
I saw a lot of conflicting posts from you and from others , where people would confirm and then disconfirm something.
It would be helpful if there was a final edition. But I also,started to read through "kapitan" thread. Txgrwhite offered to send me some more info.
So I hope I'll be fine.
Thank you for your help,though. I can always start reading through the 18 pages again ;-)
Last edited by BMW2014; 03-09-2014 at 11:08 AM.
I don't think there's a definite guidebook on how to do this.
Current Cars:
1994 BMW 850 CiA (2017 km). My black on black Wokke'd 5.4l V12 autobahnmuncher
1992 Donkervoort S8AT (105k km). The mad dutch "Super 7." 300hp/ton of turbo power!
2013 VW Caravelle 4Motion (57k km). A dark wine red 180PS/400Nm 2.0 BiTDI rocketvan
2007 SMC F-Kart 50. 88cc of street legal go-kart hilarity, and a 1968 Cadillac Coup้ DeVille Convertible 472.
"The best way to go broke-by-german-car is to buy an 8 series bmw with a v12" - Perc
"Torque is like pron. You can't really define it, but you will recognize it." - ElToro
I don't think it's quite to that stage yet - definitely still at the "most, if not all of the info you need is out there somewhere, but you'll have to do a lot of reading/digging on your own" stage.I don't think there's a definite guidebook on how to do this.
Pretty much a "dig in, you'll run into a couple of snags here and there, but you'll be able to get help here to finish it up" project
I see...
Well, I was trying to plan ahead as much as I could as to what I will need to do the swap. The size of the project got me spooked a little, but once I can sink my teeth into it it will be more obvious as to what I need to do. The M73 isn't here , yet and so I was making a mental plan of what I will need.
Thank you all for your help so far
I say just jump on and start. Create a build thread and post progress and pictures. I am sure that most of us will pitch in our 2 cents as you move forward. We all want to see you successful especially after what you have gone through.
Currently I just don't have the time to set up a DIY manual. I'm trying to update this thread as much as possible in between by editing my initial post.
When sourcing the M73 try to avoid the M73N. It has a water cooled alternator and the water pump can't be used while the M73 pump can be used on the E31.
And if anyone finds some conflicting information just PM or email me and I will happily try to clear the confusion.
Thank you for the info on the M73N engines.
The conflicting information didn't come from you , but from responses that were posted after your posts. I hope I didn't insult you with my post.
Craig
1991 BMW 850i Diamond Schwarz / Silbergrau Hell Nappa
1998 BMW 540i (Supercharged) Arctic Silver / Schwarz Nappa
1999 BMW 528i Touring Titan Silver / Schwarz leather
1995 BMW 328i Cabriolet Schwarz / Silbergrau Hell leather
fantastic work!.............. much respect.
So, this tbread hasnt had activity in a while. Any updates?
'93 850Ci - Mineralwei฿ Metallic
2001 740iL - Titansilber
ALPINA B7 -Alpinwei฿ III
...the price of cool ain't cheap!
Well Im about to tackle this conversion. My M70 is toast. I guess I would be able to save it if I went through all the trouble of trying to save the M70 engine and completely rebuild it. But from what I understood its time consuming and pretty pricey compared to to this conversion since in my case, the rings are toast.
Anyway, I ordered a M73 from a '96 750 with really low miles. Comes with a 6 month warranty. I have about a week until the engine is in my garage. I already have the M70 out of the car.
I read this thread about 2-3 times and I copied and pasted the comments that will help me speed up the build instead of sitting and trying to figure out what to do. hahaha Ill probably run into that a few times but any little helps.
These are the items that seem to "scare me" the most:
-AC compressor pully from M73 compressor needs to be swapped over (smaller diameter). = My M73 motor has no accessories on it. So I how screwed am i for that? I am not sure If you can purchase the pully by itself.
-A small cut out is required on the power steering pump side for the lower CPS sensor. Can be seen on pic #3 = this picture is not showing up for me, actually a lot of pictures are not showing up for me in this thread. And the ones that I can see are blurry and have a giant "photobucket" watermark on them. I tried a few different computers/devices and same result. I am a little SOL when it comes to pictures from this thread. If anyone has a picture of this please let me know.
-The M70 PS pump has a support bracket which mounts to the side of the M70 upper oil pan. This breacket needs to be modified as well to make it mountable to the M73 pan.?= any picture of this? Or is this a more of a DIY as you go?
I was freaking about about the exhaust adaption issues but then I remembered.... I want to do a custom exhaust anyway. Use a X pipe instead of the resonators, use Magnaflow mufflers and install new catalytic converters (if anyone can recommenced a good brand for high flow cats please share), and new tips. I am thinking about just playing around enough "to make it work" for the time being and have a shop do a proper job. I know Wokke has his own exhaust solution that can be purchased for this so Im glad I have a back up if things change. Also while there is some discussion here about cutting and girding certain stuff, If I just swapped over the whole timing cover (front and rear) that should eliminate the the need for such work? It seems I am getting mixed information. I pretty much want to use as much of my M70 things as possible since it only had 110k miles.
The only other question I have is more or so tuning related. Since the ECUs are M70 ones, would Wokke V2 chips work and yield improvement? I know Wokke mentioned in this thread about using "remapped ECUs" but was that a custom tune or???
I will probably have a good amount of left over parts after this, so this might give me an excuse to deal with more V12s. I know whats going to happen with the M70 block already, Iv been wanting a nice automotive themed coffee table for a long time.
I'm in the home stretch on this one right now - I went the hybrid approach with M73 block/M70 heads (+Schrick cams) and all the accessories/parts from the m70 moved over also. We'll see what issues pop when it's time to drop the motor in...
FYI - if you're going to go with the M73 heads, you'll need to fabricate your own adapters for 2 of the 4 manifolds - no one has them (Wokke included).
[QUOTE=rockytt;30359540]I'm in the home stretch on this one right now - I went the hybrid approach with M73 block/M70 heads (+Schrick cams) and all the accessories/parts from the m70 moved over also. We'll see what issues pop when it's time to drop the motor in...
FYI - if you're going to go with the M73 heads, you'll need to fabricate your own adapters for 2 of the 4 manifolds - no one has them (Wokke included).[/QUOTE
I found another thread (https://www.bimmerforums.com/forum/s...73-Swap-Begin!), and yea you're right, seems like the rear manifolds from the M70 are plug and play on the M73 heads, but the front ones need to be modified. So like you are saying, either do a adapter plate or cut the M73 flanges on the manifolds and weld them to the M70 ones. I guess my confusion is that I thought I can use the M73 manifolds after removing the EGR stuff, and weld the holes and all that will be in my way are the M73 downpipes, which I thought is the main issue. Hence Wokke being able to provide with custom downpipes (as I was told). I guess there is multiple ways you can go about this?
Worse case is I design the adapters on CAD and have someone machine them. I wish I had space for a CNC machine (might be my next investment), all I got is 2 3D printers that at best I can run prototypes for fit and test purposes.
I guess my other concern is getting the most out of the M73 with the M70 electronics. It seems like I can use wokke V2 chips and I should be fine? Or do I need a custom tune? I can do a chip swap but I have no experience when it comes to tuning. There is a lot of tuning shops with dynos where I live but I am hesitant as most of these tuners just see modern cars with turbo engines. My ultimate future back up plan is that I keep my M70 heads, fully rebuilt them, dish out the $1700 for Schrick cams and build a 2nd motor and maybe swap that into a future E31 or E32 or maybe my own E31. Id like to stop working on this particular E31, its been in the making for about 9 years now. I only owned it for 3 out of the 9 years.... hahaha
- nope - there was talk of this, but zero demand, so he never made these for production.Hence Wokke being able to provide with custom downpipes
M73 w/M70 electronics + Wokke V2 chips is a great way to go. Someone had done a custom tune for the M73 setup with M70 electronics and it provided no gains over the Wokke chips. Toughest part of that build is just the exhaust manifolds/downpipes. (And IIRC, it was 1 front and 1 rear from the other side that needed to be modified - check with dragon850 though)
- tough to find these days, I got lucky and found a fellow board member who'd purchased a set for a future build that never happened.dish out the $1700 for Schrick cams
Thanks!
Im getting all excited about this swap. My dad will be helping me with it, at the end of the day I like to plan ahead, my dad just wants to jump straight in and go piece by piece when we have both motors side by side. So hes telling me not to worry.
I still have a few questions:
-I purchased Bosch 62415 injectors for my M70 3 months ago. Will these still work or am I looking at getting different injectors for everything to work together?
-Thinking about getting the Elring 11129059239 Cylinder Head Gasket Kit or the Reinz one. To me it looks like most of the stuff is there. Can anyone confirm?
-Thinking about getting a new water pump. Just because with all the older BMWs i owned, the water pump seems to be the one thing that always goes. For this build its the M73 water pump thats used? Please correct me if I am wrong.
-I am not sure if I have the ASC+T option. I do have a ASC button near the shifter. Im only asking this because of what I read here about the oil pan. Curious to find out if I have +T option, how does one find that?
-I was told that with this swap the 3.91 diff would be a great choice. Is this true? I do plan on driving the car on the highway etc. I do have the 4 speed auto in my car. I read somewhere the 3.91 diff isnt the best for a daily driver or highway driving.
Do the "diff" swap, it's worth it.
Considering the stock ratio is 3:64 going to 3:91 isn't that radical. Swapped diffs years ago & I still cruise effortlessly up/down the "405" @ 80mph here in Southern California during the hours from 4am to 6am....weekends only!
1993 850Ci.....18 years & 165,000 miles and counting!
Bookmarks