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Nwe to forum, here's the 1st question

Discussion in '40- & 55-Series Tech' started by synergist, Mar 7, 2004.

  1. synergist

    synergist

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    Howdy guy's,

    First tme on this forum and it looks like you guy's have an idea whats going on!

    So heres my questions:

    1: I have a 76' fj55 2f and my old man and i have just pulled it apart for a rebuild, its .040 thou over size, do you know by how much this might increase power?

    2: The pistons have 4 rings, are these 3f pistons? Because 2f pistons only have three rings?

    Cheers and thanks in advance!!
     
  2. Landpimp

    Landpimp

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    no real clue but what I can see both 2F and 3f pistons have the same #of rings, 3 I believe. Maybe the pistons are aftermarket? but to be honest I dont have a clue about internals of motors


    [quote author=synergist link=board=1;threadid=12713;start=msg116838#msg116838 date=1078700489]
    Howdy guy's,

    First tme on this forum and it looks like you guy's have an idea whats going on!

    So heres my questions:

    1: I have a 76' fj55 2f and my old man and i have just pulled it apart for a rebuild, its .040 thou over size, do you know by how much this might increase power?

    2: The pistons have 4 rings, are these 3f pistons? Because 2f pistons only have three rings?

    Cheers and thanks in advance!!


    [/quote]
     
  3. Rice

    Rice SILVER Star

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    The gain in horsepower from a 0.040 overbore is minimal. Figure a little less than 1 horsepower for each cubic inch you gain from boring. Boring 0.040 gives you almost 4 cubic inches more displacement so figure about 3 added horsepower. More than that was used up by having 4 rings on the pistons instead of 3. The reason for boring an engine has less to do with power and more to do with having a clean fresh ROUND bore to seat the new rings in.

    Rice