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Technical Flathead pan rail cracks?

Discussion in 'The Hokey Ass Message Board' started by revkev6, Jan 15, 2017.

  1. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    Just picked up a 59 block today and I found some pan rail cracks that go around the center main on either side. It's a factory relieved block that was rebuilt with crank and rods ten under and the bore 60 over. Looks like all the bores have sleeves. It was a freebie that had a very good pan so I figured I would grab it at least to play with and tear it down with my 7 year old.

    What's the concensus on the death bell on those cracks? One goes down inside the crankcase area and stops. The other side is on the rail only. The real killer is this motor although crusty on the outside seems to clean up really nice on the deck. I haven't seen any real factory relieved motors in person are they actually considered better or worse for the street these days? I am looking to build a motor on a scat rotating assembly.
    [​IMG][​IMG][​IMG][​IMG]

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  2. andyg
    Joined: Aug 10, 2007
    Posts: 560

    andyg
    Member

    That block froze and busted most likely. Would be practice material if I owned it. That's a shame too. Not much you can do with that one but cut it up and practice porting and flow bench work.


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  3. flatjack
    Joined: Feb 13, 2007
    Posts: 975

    flatjack
    Member

    I agree. With only 3 mains, there is a lot of stress in that area. I can take or leave relieved blocks.
     
  4. I think that block is done. If you come up with a standard bore block I wouldn't bore it to .060 just because you have that set of pistons. When buying a block to replace that one I would have an agreement with the seller it passes a Mag test as well as a Sonic test on all Cyl walls. I also wouldn't build a Flat Head motor without having that done first.
    The Wizzard
     
    my2nd40 likes this.

  5. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    I was planning to use this block and build a home flow bench for testing. I actually think the relief is bad thing for this purpose.

    Just as a question. If I wanted to bore out a motor like this that's 60 over with sleeves what's possible?

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  6. 42merc
    Joined: Dec 19, 2010
    Posts: 894

    42merc
    Member

    What makes you think this block has sleeves ? Looks like a head gasket imprint to me.
    Oh yeh, I think the block is junk.
     
  7. andyg
    Joined: Aug 10, 2007
    Posts: 560

    andyg
    Member

    Sonic test would give you an exact answer. Most say keep at no less than .100" cylinder wall thickness. The sleeves look fairly thick to me but I can't say what the limit would be.


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  8. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    There is a 100 thou or so ring around the cylinder on the top even in the relief

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  9. andyg
    Joined: Aug 10, 2007
    Posts: 560

    andyg
    Member

    That's what putty is for. It would be fine for testing. Just build up when needed with epoxy or putty when testing.


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  10. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

  11. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    Crank rods and pistons out! Messy but better than expected so far. Must have been a low miles rebuild. Definitely out of a big truck as it had an 11" clutch

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    [​IMG]
     
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  12. drtrcrV-8
    Joined: Jan 6, 2013
    Posts: 1,707

    drtrcrV-8
    Member

    In the day one of the most popular & reliable circle track engines was the 276" which was a .125" over with a Merc 4"crank, so if the block was any good, you'd still have plenty of room to re-bore left on this one.
     
  13. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    We will see if I do anything with this block beyond testing. If I find no other issues after disassembly I will attempt to weld up the pan rail cracks.

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  14. revkev6
    Joined: Jun 13, 2006
    Posts: 3,352

    revkev6
    Member
    from ma

    Well... things got interesting today on my flathead motors in general. It was coincidental that I got this motor with a cracked pan because I tore down the motor in my roadsters today to find that it's been running with 30 inches of weld along the pan rail for the last 25 years!

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    kidcampbell71 likes this.
  15. deucendude
    Joined: Oct 31, 2008
    Posts: 669

    deucendude
    Member
    from norcal

    I just got one with a big crack along the pan rail too. It is junk.
     

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