Announcement

Collapse
No announcement yet.

M52 crank, b27 rod, b25 piston - m20

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
    #1

    M52 crank, b27 rod, b25 piston - m20

    crank______m52 - 42mm
    rod________b27 - 130mm
    piston______b25 - 34.2mm
    -------------------------------------
    stack___________206.2mm
    -------------------------------------

    deck____________206.2mm
    gasket____________1.75mm
    -------------------------------------
    ________________207.95mm

    difference________-1.75mm


    OK, could someone help me figure:
    a) what is the CR as is?
    b) what would i have to shave on the block to get it to 9.2CR?

    With my previous posts of not going the shaving route, i found a couple of guys that threw the M52 crank with b27 rods and b25 pistons. They didn't shave the block, but it would be easier to shave the block and get an adjustable cam gear to reset the timing.

    Robert
    Last edited by rvaughnp; 03-23-2010, 10:09 PM.
    Tags: None
    #2
    ~9:1. Don't shave anything.

    Comment

      #3
      Really? 9.2 with a stock gasket? Do you know someone who has done this?

      Comment

        #4
        Do you mean stock gasket?

        Everything I've read in my research has led me to that conclusion.

        Comment

          #5
          yeah stock. edited it. thanks. well, that sound like a winner. i'll see what others have to say. I had read where the power dropped off around 6000, but if it works i wouldn't be taking it above that much anyway. that and i might give it to my daughter.
          Thanks for the input.

          Robert

          Comment

            #6
            Most h/p from a NA m20? - Page 2
            http://forums.bimmerforums.com/forum/showpost.php?p=18530921&postcount=44
            Bimmerforums is the preferred online BMW Forum and community for BMW owners. At Bimmerforums, you will find technical how-to information maintenance specifics audio advice wheel and tire combinations and model specific details not found anywhere else. Our professionals are here to help make sure you find the answers you need to your questions and our community is here to help other brainstorm ideas for the future.

            Comment

              #7
              Awesome, thanks felix. I was expecting to spend a lot of time researching. He seemed to have it down.
              Well... good bye "budget" shave, hello "budget" crank. I'll keep posting.

              Robert

              Comment

                #8
                I just reread and a little of the info is off. Not from his calculations just the "quoted" information in the top of the post.
                1) the actual "deck" is 206.2 for the m20.
                2) the "stack height" 1/2 crank throw, rod, piston is 206.7 for the b25 and 206.2 for the 2.7.
                http://www.r3vlimited.com/board/showthread.php?t=157679 has pics of multiple setups but with the stock 2.5 and 2.7 at "deck" height showing the 2.7 even with the deck.

                That being said... i would still gain more air fuel per rotation.

                Robert

                Comment

                  #9
                  Originally posted by rvaughnp View Post
                  He seemed to have it down.
                  :) felix=phelix :)

                  Comment

                  Previous template Next
                  Working...
                  X