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Flathead block crack

Discussion in 'The Hokey Ass Message Board' started by LKPar1270, Oct 29, 2010.

  1. LKPar1270
    Joined: Oct 31, 2008
    Posts: 46

    LKPar1270
    Member

    I've got a '51 RT Flathead with the familiar crack between the water jacket opening and head bolt hole. I wasn't really worried about it until today when looking closer I discover the crack goes past the head bolt hole toward the valves about 3/4 inch. What's the chance of drilling the end of the crack and stopping it?
     
  2. 59ab
    Joined: Feb 19, 2009
    Posts: 206

    59ab
    Member

    Certainly worth trying. Good luck!
     
  3. LKPar1270
    Joined: Oct 31, 2008
    Posts: 46

    LKPar1270
    Member

    I'm thinking just a small hole, 1/8 or so would be better than a threaded hole with a bolt in it. My thinking is a smooth hole would be stronger and less likely to let the crack restart than one with the sharp ridges and valleys of a threaded hole. Would the head gasket block any coolant seepage with this kind of fix?
     
  4. lowsquire
    Joined: Feb 21, 2002
    Posts: 2,519

    lowsquire
    Member

    yeh it may seal a small hole..maybe not though.depends where it is. . make very sure you drill it past the end of the crack..thats the important bit.
     
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  5. Screamin' Metal
    Joined: Feb 1, 2009
    Posts: 506

    Screamin' Metal
    Member
    from Oklahoma

    yup, drill 1/8 hole at the end and v that puppy out and lay in some brass. or, get a sealace kit and sew her up....then rough her down close,flap wheel to within.030, blue her up, file down close then hone to perfection.
     
  6. Captain Chaos
    Joined: Oct 16, 2009
    Posts: 577

    Captain Chaos
    Member
    from Missery

    I saw a guy that does crack repairs, wont say how but from studying his finished work it looks like small hole with brass dowel driven or screwed in then each one overlapped til the crack is filled .
     
  7. pretty detailed "how to" in tex smith's "the complete ford flathead v8" book. done with irontite plugs.
     
  8. LKPar1270
    Joined: Oct 31, 2008
    Posts: 46

    LKPar1270
    Member

    [​IMG]More problems....more cracks. I have a crack near the valve seat on one intake valve. Is this a place that works well with stitching?
     
    Last edited: Nov 5, 2010
  9. ablebob
    Joined: Jul 29, 2009
    Posts: 75

    ablebob
    Member

    If you are interested I just listed a Irotntite pressure tester & pinning kit in the misc classified section. I'm downsizing my shop. I used to pin a lot of cracks, even thru seats. I'd say the success rate is 90%. There is also a liquid called fluidweld that seals up small cracks in aluminum & cast iron. Never had a crack start from threads in a pinning hole. My guess is the irregular surface of the threads spreads out the stress in many directions.
     
  10. Ancient Rodder
    Joined: Nov 1, 2010
    Posts: 43

    Ancient Rodder
    Member

    Yep, thats the way we used to do it. Drill, tap, brass screw, keep overlapping till you get past or to the end of the crack. The 8RT has head bolts, change all of them to studs, clean stud holes with a thread chaser, coat the block ends of the studs with ceramic sealer prior to reinstalling them ( I'd have the block acid dipped prior to doing any thing ) when you get through and ready to refire it up put a product called "Liquid Glass" in the coolant, it will seal any thing you may have missed. After having said all that, there are still good blocks out there of the 8BA/RT configuration.

    JMO
     
  11. JonF
    Joined: Mar 6, 2010
    Posts: 138

    JonF
    Member

    You said "coat the block ends of the studs with ceramic sealer prior to reinstalling them ", do you recommend a brand name sealer and where can I buy it??
     
  12. Ancient Rodder
    Joined: Nov 1, 2010
    Posts: 43

    Ancient Rodder
    Member

    I'm using "Moroso Ceramic Engine Seal". I dip the stud threads in the bottle and screw into the block. I've not used it as a block sealer as they describe in the directions, I have been useing "Water Glass" since the "60s" with good results. Picked this tip up from a diesel enginen shop.
     
  13. Ancient Rodder
    Joined: Nov 1, 2010
    Posts: 43

    Ancient Rodder
    Member

    I originally said "liquid Glass", the correct name is "Water Glass". sorry bout that.
     
  14. ironpile
    Joined: Jul 3, 2005
    Posts: 915

    ironpile
    Member

    I`ve heard and seen a lot of good things about the stitching system.Might be the same as sealace system.Any concentrated heat could cause problems with an old and seasoned block.I would like to try it myself but the kit is too expensive for experimentation. Good luck what ever way you go,and keep the forum up to date on results.
     
  15. aaggie
    Joined: Nov 21, 2009
    Posts: 1,506

    aaggie
    ALLIANCE MEMBER

    I have an old book written for Model T Fords and it has a chapter on repairing cracks in the block. It describes drilling a series of holes plugging each with a brass rod and grinding off the excess. The book was published in the late teens and has all sorts of tips and instructions.

    There is a chart that shows how much gas is in the tank by dipping a stick in and measuring the wet line. Another shows how to sew up a split sidewall in the tires. The best is instructions on filling the Acetylene generator on the running board and lighting the headlamps with a match.
     
  16. LKPar1270
    Joined: Oct 31, 2008
    Posts: 46

    LKPar1270
    Member

    Since this block has been bored enough to need sleeves (didn't now they didn't come that way) I've decided it's not worth the time or cost of stitching. I found another RT block today (a '50) and will junk the cracked block. The pistons are stuck in the 'new' block. Visual inspection doesn't show any cracking, even at the usualy places between the head bolts and water jacket holes, so I think it's solid. I should be able to use the crank and rods and maybe the cam out of the engine I'm going to junk.
    Thanks for all the help and good information.
    Next step: press those pistons out and get this thing hot tanked, more closely inspected, bored and lightly decked, and start building.
     
  17. LKPar1270
    Joined: Oct 31, 2008
    Posts: 46

    LKPar1270
    Member

    Another question already. I find there are lots of new old stock piston sets available for the flathead V8. Will any set for the 239s fit this block, or are there differenced between the block styles? What do I need to look for?
     

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