Register now to get rid of these ads!

Hot Rods Low flathead compression

Discussion in 'The Hokey Ass Message Board' started by rodderbilly, Oct 28, 2018.

  1. Hi all hambers ... after lot of smoke from oil filler tube today I check the compression on my 8ba....all cylinders are around 60 65 psi.... engine around 130 deg...... Time to rebuild the engine I know..... Is 0.125 bore over and 3.75 stroke.... What you suggest for a more bore and a good stroke? Thanks
     
  2. F-ONE
    Joined: Mar 27, 2008
    Posts: 2,262

    F-ONE
    Member
    from Alabama

    I might try adjusting the valves first.
    Secondly, All it may need is rings. Check for excessive taper.

    If the block needs to be bored, only bore for the next size rings and pistons.

    0.125 seems excessive to me. I have a 8BA 0.040 that cracked a cylinder.
    Due to corrosion and casting flaws...the less over bore, the better.

    3-3/4 is the stock Ford crank. The 255 Mercuries has a 4" stroke and a Mercury crank was a popular swap. With that said, the stock Ford cranks does fine.
     
  3. 19Fordy
    Joined: May 17, 2003
    Posts: 6,873

    19Fordy
    Member

    Follow F-ONE's advice. Bigger is not always better.
     
    Petejoe likes this.
  4. flatjack
    Joined: Feb 13, 2007
    Posts: 893

    flatjack
    Member

    There are many flatheads running with .125 overbore. Mine has been running for almost 25 years now.
     
    Register now to get rid of these ads!

  5. Yes ..i know 0.125 is a bit big bore…...looking on ross pistons i see they have two sizes of bigger pistons….actually i have a 3.313 bore…...ross has 3.342 and big 3.375...…….just i'm looking the best choice...thinking to upgrade with a stroker crank……..F-one is right…..first of all i try adjusting valves….
     
  6. F-ONE
    Joined: Mar 27, 2008
    Posts: 2,262

    F-ONE
    Member
    from Alabama

    I have a block that failed with a .040 over bore. There's lot of factors some going back to the casting. Any time you bore one of these old engine....be prepared to sleeve.

    That would save my block but I have another.
     
    rodderbilly likes this.

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.