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will a bobbed crank for 2.8l stroker balance out?

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    will a bobbed crank for 2.8l stroker balance out?

    I'm over thinking this since I've been saving up for awhile and all the stuff that could go wrong is running through my head that could happen.

    anyway do the bobbed cranks balance out even or is it just pissing money away putting a crank in that will eat the bearings and not last that long?


    cliffs: scared like a bitch about getting machine work done and it not be going worth it


    it's an m52b28 crank with e rods (130mm) and I pistons everything will be stock except maybe a regrind cam later on. tuning by sssquid

    Sent from my VS930 4G using Tapatalk

    #2
    Should not be using bob weights on an inline crank.

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      #3
      Originally posted by Wh33lhop View Post
      Should not be using bob weights on an inline crank.
      This. 9 times out of 10 it's pointless.


      Leave Me Transaction Feedback

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        #4
        Originally posted by TurboJake View Post
        This. 9 times out of 10 it's pointless.
        10 times out 10.


        An inline 6 cylinder engine crankshaft is balanced only to itself, there is no balance factor so no bob weights are used.
        Lorin


        Originally posted by slammin.e28
        The M30 is God's engine.

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          #5
          so it's technically impossible to get the crank to balance back out after the counterweights have been shaved for piston clearance? and if so would it make the engine less reliable and should I just not do it?

          Sent from my VS930 4G using Tapatalk

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            #6
            Typically you need to cut down the counterweights to clear the pistons with this setup. After that, the crank needs to be rebalanced. It cost me about $75 for cutting the counterweights and $160 for balancing.

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              #7
              redlightpete have u run this? i want this to be a long term 150k runner I'm not racing it

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                #8
                Originally posted by kickinindian View Post
                redlightpete have u run this? i want this to be a long term 150k runner I'm not racing it

                Sent from my VS930 4G using Tapatalk
                The short block is built, but it's still sitting in my shed. Hopefully I'll get it installed later this year.

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                  #9
                  Gotcha does anyone else have this setup and had it running for a while

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                    #10
                    It will not be a problem. You are not removing that much material.

                    Get the crank balanced after it is machined and all will be ok. You are thinking about this too much.
                    Lorin


                    Originally posted by slammin.e28
                    The M30 is God's engine.

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                      #11
                      Originally posted by LJ851 View Post
                      It will not be a problem. You are not removing that much material.

                      Get the crank balanced after it is machined and all will be ok. You are thinking about this too much.

                      Thank you! that's what I needed to hear how much should I tell them to take off?

                      Sent from my VS930 4G using Tapatalk

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                        #12
                        Have you seen bulletride's thread? He did the same engine without issue.

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                          #13
                          it might be an issue if you were going to rev it extremely high, but there would be bigger issues doing that anyway. i would not worry its been done before.....its worth remembering that elsewhere in the world there are M52B28 cranks that fit without machining. presumably this means the mass of CW is approximately the same as what you will end up at?
                          89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

                          new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

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                            #14
                            Yes, the counterweights need to be cut down.

                            Any competent machine shop (with a balancing machine) will be able to balance it without issue!
                            BimmerHeads
                            Classic BMW Specialists
                            Santa Clarita, CA

                            www.BimmerHeads.com

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                              #15
                              I think two different questions are getting confused here:
                              1. Do you need to get the crank balanced after machining the counterweights to fit? Yes
                              2. Is it a problem that the counterweights are smaller? No. It might be an issue in a vee configuration or a single, and then you might add "bob" weights to compensate.

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