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Thread: M70 Build

  1. #1
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    M70 Build

    With the eco down turn my prioreties have changed a bit and money has dryed up for the moment is there still any interest in a HO V12?

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    Ho m70

    Hello,
    What do you got?
    Thanks,
    Joe

  3. #3
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    YES...There's always been an interest...What you got going?

  4. #4
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    http://s220.photobucket.com/albums/dd109/smokumxxx/M70/
    Im doing a N/A engine only.
    Old engine with modern tech
    finding some one to do the cam and unraveling the heads
    has taken alot of time.
    Last edited by smokum; 04-12-2011 at 10:53 PM.

  5. #5
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    The heads- geometry is laid out for you right here-

    http://www.mwrench.com/Whitepapers/B...Geometries.wmv

    Cams....It's this one or a custom grind...

    http://store.vacmotorsports.com/schr...set-p1113.aspx

  6. #6
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    Thanks rich454
    i have already read everything thats out there,
    to be honest those cams are not worth the trouble of getting ,im going full rollor and beehive valve spring setup.
    Also the style of intake im planing to use is of a ram type.
    Those cams dont even come close to the lift i need and have modded the heads for.

  7. #7
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    I'm still at the mock up stage in my build- dry sump is taking more time resources than I expected... So I really haven't started the final engine build. I have a running mock up engine- then going to build the second one I have laying around here.

    Since the pistons are positive deck- I see problems w/ milling the heads...and piston to valve clearance...

    What's your thoughts on duration/lift- w/o screwing up drive-ability?


    Looking at your flow numbers....I guess if you use the 1.5:1 to compare it to a similar sized V8- it's really not that low...

    Here's a generic formula-

    .257 X cfm X # of cyl.'s = est. hp

    Fortunately my car will weigh in 1000-1200lbs than an 850 and about 1500lbs than a 750...

    Richard


  8. #8
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    Lookin good on the vette,
    Well rich since it doesnt compramise any R&D that i have done on the heads
    I will tell you that you can have custom pistons made for the M70,
    Rings and all will be around 140 per piston which i think isnt so bad.
    But if you are on the cheap you can resurface the heads and retard the cam timming a little to clear the pistons.

  9. #9
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    On the cheap and M70 are an oxymoron.... That's why so many V12 conversions are NEVER finished...not to mention zero transmission options- an automatic that there's really no way to control inexpensively or the 6 speed which is several thousand dollars.

    I think the donor car and the extra M70- might have less than $800-900 in it- That's been the only thing you could call cheap!!!

    My buddy who owns a Machine shop just finished a M60 rebuild- rings from the dealer were $125 PER piston...has some custom made for $190 for the COMPLETE set...

    Anyway- like I said- I haven't really figured out my actual build on the M70...

    I've sorta looked at the engine as it is what it is- The engineers set out and accomplished just what they wanted to to do- a torque monster to move luxury vehicles.


    Richard

  10. #10
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    Quote Originally Posted by Richard454 View Post
    On the cheap and M70 are an oxymoron.... That's why so many V12 conversions are NEVER finished...not to mention zero transmission options- an automatic that there's really no way to control inexpensively or the 6 speed which is several thousand dollars.

    I think the donor car and the extra M70- might have less than $800-900 in it- That's been the only thing you could call cheap!!!

    My buddy who owns a Machine shop just finished a M60 rebuild- rings from the dealer were $125 PER piston...has some custom made for $190 for the COMPLETE set...

    Anyway- like I said- I haven't really figured out my actual build on the M70...

    I've sorta looked at the engine as it is what it is- The engineers set out and accomplished just what they wanted to to do- a torque monster to move luxury vehicles.


    Richard
    The M60 is alot more common then a M70 BUTT "big butt"
    Have him quote you 10.5:1 or 11.0:1 c/r pistons for the V12 just to see if he can do better rings and all, woulodnt hurt.
    To compare the cost of hot rodding this motor to the cost of hotrodding an american motor would be dumb.
    The only way to look at the cost vs gain is supercharging /turbo vs fast ramp cam, high compression pistons, rollor valve train, beehive springs modded heads , custom headers and custom intake.
    I have done the math with those flow numbers that i have posted and the out come is very nice.
    Perspective :
    Who in there right mind tricks out a engine and leaves on the stock intake and exhaust manifold???

  11. #11
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    I like your mindset on modding the M70/73.

    You can get quite quite good power with cams, porting, headers and intake.

    I do not compare a BMW V12 against a Chev lsx or any other push rod motor.

    It is what it is, and that is a wonderfully smooth, light motor with 12 cylinders.

    It has huge torque down low due to having 12 pots and that smoothness only a 12 can provide- it all comes down to harmonics.

    To the ear that is that ripping silk sound of a hot v12 on song.

    My preference would be a hot cammed m73 with 12 throttle bodies and ram tubes.

    Man ........... What a symphony of power!

  12. #12
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    This is just like the threads that get posted in the 8 section is just going to go in circles.

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    I am also interested, but I have yet to see anyone build a HO 12. I have been kicking around the idea of ITB's from a motorcycle, the cost would be considerably less than anything else on the market. But if the heads cant handle the flow what would be the net gain?

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    Quote Originally Posted by Monty540 View Post
    I like your mindset on modding the M70/73.

    You can get quite quite good power with cams, porting, headers and intake.

    I do not compare a BMW V12 against a Chev lsx or any other push rod motor.

    It is what it is, and that is a wonderfully smooth, light motor with 12 cylinders.

    It has huge torque down low due to having 12 pots and that smoothness only a 12 can provide- it all comes down to harmonics.

    To the ear that is that ripping silk sound of a hot v12 on song.

    My preference would be a hot cammed m73 with 12 throttle bodies and ram tubes.

    Man ........... What a symphony of power!
    The BMW v12 is a 304ci engine in order to compare it fairly i would have to find some thing close to it.

  15. #15
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    Quote Originally Posted by RUFAZZ View Post
    I am also interested, but I have yet to see anyone build a HO 12. I have been kicking around the idea of ITB's from a motorcycle, the cost would be considerably less than anything else on the market. But if the heads cant handle the flow what would be the net gain?
    Stock, the M70 is being choked the stock heads are poopy unless modded.

  16. #16
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    That is my point, no one that I have heard of has been able to successfully mod the heads. The only way to get any real power out of the 12 is by forced induction

  17. #17
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    Going in circles...The engine has been around for 24+ years and other than adding cubic inches-and forced induction -I haven't seen anything to write home about....or spend money on...

    A Hotter cam-

    Cam grinding for the M70 series is not easy

    "The cams for the M70, S70 or M73 have a very complex geometry! The heads are identical and interchangeable from side to side so the rotation of the cams in respect to the valves and actuators is reversed from side to side. the cams are not centered between the exhaust valves and intake valves, the leading ramp and the trailing ramp is reversed from side to side, and I could go on and on!

    The M73 engine uses sintered metal lobes that are heated and placed on a hollow shaft where they shrink and lock in place, they are not suitable for re-grinding, as John said, the M73 cam bearings were greatly reduced in diameter over the M70. Can not reduce the diameter of the M70 cams to make them work in a M73" (mwrench)

    And if you could find a hotter cam?....

    It will respond , not as well as with a good head

    "There will be some HP gains but not as much as with heads that flow well or could be made to flow better.

    The S70 over the M70 is a good example, most of the HP gain is from displacement, some gain from increase in compression ratio and lastly increase in valve lift and duration in that order. CSI cams are about half way between the stock M70 cams and Schrick design.

    The V-12 was not and engine designed for serious tuning, just a torque monster to move luxury vehicles. It is a decendant of the M20 6 cylinder engine. Source of this information is the book written by Dr. Karlheinz Lange, who was director of engine development for BMW." (mwrench)

    I rest my case.....

    The ITB's would be cool-in the looks department-


    Richard
    Last edited by Richard454; 04-21-2011 at 10:43 PM.

  18. #18
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    LOL laughable
    Rich let me tell you something, if you think that the M70 is the only engine in history with shitty flow heads you are soo sadly mistaken.
    Everything that MWRENCH has done was long ago and he has thrown in the towel on this engine long ago.
    If i told you the other engines like the M70 it would give away the changes made to improve the flow.
    Look at a few of the flow charts i have posted (100 bucks a pop i might add) the very first 1 is oem intake and oem exhaust.
    after every change i flowed them to see if i made any progress.
    If i didnt make any more numbers i would have given up already.
    BTW no one makes a cam, intake manifold or exhaust worth a shit for this engine thats why no one trys.
    Last edited by smokum; 04-21-2011 at 10:59 PM.

  19. #19
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    [ame]http://www.youtube.com/watch?v=x31KyRZLR7c&feature=related[/ame]

  20. #20
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    Quote Originally Posted by smokum View Post
    LOL laughable
    Rich let me tell you something, if you think that the M70 is the only engine in history with shitty flow heads you are soo sadly mistaken.
    Everything that MWRENCH has done was long ago and he has thrown in the towel on this engine long ago.
    If i told you the other engines like the M70 it would give away the changes made to improve the flow.
    Look at a few of the flow charts i have posted (100 bucks a pop i might add) the very first 1 is oem intake and oem exhaust.
    after every change i flowed them to see if i made any progress.
    If i didnt make any more numbers i would have given up already.
    BTW no one makes a cam, intake manifold or exhaust worth a shit for this engine thats why no one trys.
    Smokum,
    I think you are taking it the wrong way Richard is probably hoping that you find a way to get more power out of the M70, as am I but everyone that has tried to this point comes up short on delivering that promised and elusive bump in power.

    I am pulling for you, I hope you can get 600hp from it cause I WILL follow every improvement that you make

    Richard,

    I agree the ITB's look cool, kinda why I would do them not to mention the sound and the possibility of improved efficiency.
    Last edited by RUFAZZ; 04-22-2011 at 10:08 AM. Reason: add response

  21. #21
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    I DO want you to succeed in making more HP....we can bench race all day...

    But it's just like my "fat" female friend...All the money she has spend on weight loss/trainers/healthy food- has lost some weight- but still doesn't look good in a pair of jeans...However- I still like her because of her personality!!!

    I'm doing the V12 because of it's personality...a monster cube big block would be cheaper AND a lot less hassle - simple bolt in with my application.

    We want real dyno numbers- I WANT you to prove the naysayers wrong. And people will be glad to pay you for the formula.

    Richard

    Last edited by Richard454; 04-22-2011 at 01:25 PM.

  22. #22
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    Awfull pic of the 8 series, btw rich i have it too.
    Im glad to hear that you guys want me to make this thing happen i soo do too
    ,that is what i am wanting to hear and how many people would still be interested in this engine is my other question?

  23. #23
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    Quote Originally Posted by smokum View Post
    how many people would still be interested in this engine is my other question?
    That's a tough question....

    As you have probably seen a lot of new 8 owners- have NO idea what they are getting into...Same w/ the older 750il's- They buy it- then want to put 20"+ wheels on it...Next the car is up for sale as soon as they find out a tune-up w/ plugs and wires is gonna cost them MORE than they paid for the car.

    However- I get at least a couple of emails a month-where some one is doing a swap and wants some info or how did I do the bellhousing...

    They are out there -but price has to be in the ballpark- not what Henry wants...

    I have access to a flowbench (FlowData FD 700) at my friend's machine shop- just have to buy my buddy lunch....I want to get into the V12 as well...but HAVE to get my project on the road before I start messing w/ mods. That's my game-plan- I hate moving targets...

    Richard

  24. #24
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    Will you bring the vette to a local meet when you are done please?

  25. #25
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    Gotta love that pic with the 12 throttle bodies!


    Ok, here is some info from here in Australia on modding a M70.

    Keep in mind that any US motor costs a bomb here in Aus.

    A easy way to spend 10grand for a injected crate motor.

    So the economics are way different down under.


    My best friend is a BMW engine builder that specializes in S36/38's but likes the 12 for the charm and character.

    This is exactly what he has done and will be doing-

    A E34 has been stripped completely and painted white.

    A engine and wiring from a e32 750i

    The motor cost was hundreds not thousands.

    A Getrag 5 speed from a Chev has been bought and painstakingly modified with machining/welding to match the V12. And that used two bottles of Gas for the Tig and lots of hours and beers.

    A lightweight flywheel and clutch is been made at the moment.

    The heads have been ported and polished to specs developed by a friend that builds Ferrari etc race motors- to get the most reliable power from the heads. They are yet to be flow but should make a substantial flow difference.

    The heads have new valve stems and a suoer precise valve angle job-
    using a mega dollar robot machine from Italy.

    The heads will be ceramic coated before final assmebly.

    Cams are reground in Aus by Crow cams to 300+ degrees- but will change to special grind for low blow turbo.

    Inlet and Exhaust-

    Lots of ways to go, but only one cheap.

    Weld a larger flange on the intakes and fit a late model M30 throttle bodies from e34. Much improved flow and dirt cheap.

    Or go wild cam and those lovely 12 trumpets through the bonnet.

    Exhaust-

    The stock manifolds are Ugly, slow flowing shit......only good for a limo.

    A custom extractor set is big bucks and a huge pain to fit.

    OR make a turbo manifold, heaps easier and cheaper by far.


    By deciding on twin turbos, my mate has saved a heap of money for exotic throttles and extractors. And quite a few busted knuckles getting it fitted.

    The Turbos are going to be from a GTR Nissan at $200 each- all 2nd hand but he has 200 to choose from. These ones shoot the waste back into the exhaust flow- so none of that farting sound.

    Injection will be most likely a 2nd hand Microtech or similar.

    And naturally a nice intercooler.

    These Turbos will provide a easy 8psi, which is more than enough for his needs. The compression will remain 8.8:1- hence low blow v12.
    He is mainly after instant response and no lag, combined with a reliable max 500hp.

    That is plenty of power for a lightweight E34.

    This is been built as a fast road car- not a dragster or drift car. Mike wants a V12 to eat M5's on drivers roads, hence the only 500hp.
    Oh and to chase a mate with a 14psi blown S38 Mike built for his E28.

    The drive-ability, smoothness of power delivery and response is what this beast is all about. The last thing he wants is a squirrelly car with a lumpy power curve.

    A primary goal is to get this modest power at a small fraction of the cost of going a hot Atmo version.

    Total for the motor and box we hope will be less than $5,000.

    That's fitted, exhaust and dyno tuned.

    Most parts required are made DIY, so that helps lots.

    Point been, it can be done cheaply but only if you DIY most of it and buy real smart.

    Now if we stayed with the Atmo build and needed a Custom set of throttles with a dozen trumpets- even with friends that costs $2-2,500.
    Add in the custom extractors/exhaust for maybe $3,000.

    And it would be pushing towards $10,000 real quick.

    Would be great sounding but less power than forced induction- so dollars one the day.

    A big chunk of the budget goes on the box- getrag 5 speed, including flywheel, clutch etc plus gas for welding etc. is about $2,500. A six speed would be great but could not find one to bolt up.

    It can all be done- but dreams cost time and money.



    I will try and find some pics.

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