BMW V8 manual conversion - thinking of making my own flywheel

Thread in 'Technical Questions' started by afterburner, Jan 19, 2012.

  1. afterburner

    afterburner New Member

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    Hey there! I have an idea and I'd like some feedback. I'm putting together a manual M60 BMW here, so I need a flywheel. I'd really like not to use the original dual mass one, but a lighter one, which sadly does not fit in my budget right now.

    I'm thinking of using a flexplate from an auto box and getting a 240mm flywheel from an in-line 6, let's say M30. Then I'd take the M30 flywheel, shave it on the lathe only leaving the friction surface and the clutch mounting surface and then bolting it to the auto flexplate (I can make holes with threads in the back of the "friction disk" from the M30 engine and then run bolts through the flexplate). Then all goes to balancing.

    Using a flexplate from a 2000+ V8 4.4 car means it will weigh around 3.8kg according to bmwfans, so the whole setup should be around 7 kg. I can use an original V8 dual mass flywheel to take my measurements about the deck height of the whole setup, so it should have the factory specs.

    Will the thin flexplate from the auto box hold the added weight? After all it's steel and some aftermarket light-weight flywheels are from aluminium. I know that I should not be messing around with something spinning with 6500RPM close to my feet.
     
  2. NORFY

    NORFY Active Member

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    Speak to crackers about a Solid flywheel, he's getting one made up.
     
  3. Ruishy1

    Ruishy1 Active Member

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    you can get custom flywheels made for a couple hundred quid. its worth having it done right if you value your feet
     
  4. afterburner

    afterburner New Member

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    All the lighter alloy/steel flywheels I've seen are 450+ quid, which is over my budget. If there's an 200 quid option I'm going to consider it. I will send crackers a PM to see what he thinks.
     
  5. Ruishy1

    Ruishy1 Active Member

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    the 450 quid ones will be already made and someone is making money on them. plenty of places will make you a flywheel .
    i did have contact details of a company that made custom steel ones for 250, but after moving dunno what the hell i did with it
     
  6. Ballbag

    Ballbag Member

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    I'm pretty sure Jeek has got a solid flywheel in his 540, worth getting in touch with him on here or Trampdrift.
     
  7. AdamChase

    AdamChase New Member

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    cant you use an m20 flywheel on the m60's? i know you can on the m50s with some modification... maybe something to look into? youd be best off asking on a yank forum as they tend to do more m6x conversions. priced up a ucc one or uuc or whatever it is?
     
  8. afterburner

    afterburner New Member

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    The V8s have different bolt pattern for the crank, can't use a flywheel from other then V8... That's why I want to use the flexplate of an auto box as a base.
     
  9. Munkul

    Munkul Active Member

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    FFS dont bodge anything you arent 100% sure about. If you end up with a couple of missing legs I suppose that £250 difference between quality could go towards your disability transport...
     
  10. 4_Stroke

    4_Stroke Member

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    A flex plate will NOT support a flywheel. The flex plate is designed to take torque only. The torque converter weight is supported by the transmission. A flywheel needs to take thrust from the clutch relese bearing pushing on the crank and bending caused by the mass offset from the crank mounting face..
     
  11. afterburner

    afterburner New Member

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    You're right guys! Gonna go another route! Will keep you posted!
     
  12. caged

    caged Drift Gibbon

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    i know you already said theyre outta your budget - but im using one from jbracing.com and its an amazinggggg piece of kit
     

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