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Technical How bad is this crack (Chrysler flathead)

Discussion in 'The Hokey Ass Message Board' started by B Ramsey, Nov 8, 2020.

  1. B Ramsey
    Joined: Mar 29, 2009
    Posts: 646

    B Ramsey
    Member

    Got this back from machinist. 6 sleeves, standard bore, cam and crank reground, etc. He didn't see this crack. He suggested to see if it even leaks, use Steel Seal or stitch bolt it. Wanted to see what the experts think.
     

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  2. badshifter
    Joined: Apr 28, 2006
    Posts: 3,344

    badshifter
    Member

    If you lock stitch it, at the very least you should check/rehone the bore, and check/regrind valve seat. That process puts pressure on the block which can/will move things around especially in that location.
    I wouldn't use a sealer at this point while you have options available.
     
    Deuces likes this.
  3. You need to pull sleeve & valve seat. Be sure you can get to both ends of crack. Stitchlock. Easy to do. Clean up pins from stitchlock. Install sleeve & valve seat. Your good to go.
     
    VANDENPLAS likes this.
  4. junkman8888
    Joined: Jan 28, 2009
    Posts: 614

    junkman8888
    Member

    What you have is a very expensive boat anchor, cracks that go into intake/exhaust ports are very difficult if not impossible to fix.
    Apparently the machinist didn't "magnaflux" the block before doing all that expensive machine work.
     
    beegator, Deuces and flynbrian48 like this.

  5. Is it a coolant passage under the crack ?

    it won’t spread anymore swing it’s touching the valve seat and liner.

    What did you pay for ?
    Seems strange they wouldn’t mag it first or even see the crack, pretty easy to spot it .

    not sure how happy I’d be putting jb weld on it after you spent as much as you did doing it the right way.

    what was your machinist thoughts on a spot stich ?
    Might have to pull the liner and the seat but it would be the correct way to fix it.
     
  6. B Ramsey
    Joined: Mar 29, 2009
    Posts: 646

    B Ramsey
    Member

    This photo help? Doesn't look like it was leaking. 2nd cyl from left. Trying to be optimistic here, these thing ain't exactly falling from trees around here.
     

    Attached Files:

    VANDENPLAS likes this.
  7. B Ramsey
    Joined: Mar 29, 2009
    Posts: 646

    B Ramsey
    Member

    Should be coolant under there.
    He said it could be spot stitched without removing anything. I couldn't drill a straight hole if my life depended on it.
    Never had any luck with JB Weld on anything.
    He swears by some stuff that will seal it called Steel Seal.
     
    VANDENPLAS likes this.
  8. I have repaired many flathead Ford’s with cracks from ports to cylinder exactly as I described above with 100% success over the last 50 years. Don’t be scared but do it correctly. It’s actually pretty easy.
     
    VANDENPLAS likes this.
  9. I would get him to spot stich it, at this point it would be 1-2 hours labour for him to do it.

    by the time you buy the kit and piss around you paid him and it’s done back at your garage.

    i JB welded a lot of jag inline 6 heads and blocks as the coolant would eat away at the material around the coolant passages, slather it in wait a day then with a big fine bastard file file it down smooth and level with the rest of the surface.
    But that was with an actual hole or gully, if I where to jb weld your crack I would V it a bit so you could pack it in there.


    Anyways, I vote for getting your machinist to spot stich or lock stich it and be done with a quality repair.
     
  10. Budget36
    Joined: Nov 29, 2014
    Posts: 6,739

    Budget36
    Member

    I think if it was to be stitched, I’d invest in an inexpensive bore gauge, or a snap gauge and check roundness afterwards. I know the process is to pull the material together, but I’d still check it
     
  11. B Ramsey
    Joined: Mar 29, 2009
    Posts: 646

    B Ramsey
    Member

    I will ask the machinist to take it back and fix it. thanks.
     
    kidcampbell71 and VANDENPLAS like this.
  12. Wonder if the machinist can determine the ends of the crack and drill for you, seeing how they missed it the first time. Then v grind it and fill with brazing rod. ( isn't that how they used to fix minor cast iron cracks in the days before JBW?) ...or am I totally wrong guys....
     
  13. BAD different expansion rates. Heat concentrated unevenly is also bad.
     
    beegator likes this.
  14. Definitely take it back and let the machinist fix it. Did he call you about the crack before doing the work or inform you after you came to pick up and pay for a finished block ready to bolt back together and get on the road?
     
  15. B Ramsey
    Joined: Mar 29, 2009
    Posts: 646

    B Ramsey
    Member

    the latter.
     

  16. Then I would be very concerned about the shops reputation. At the very least after cleaning and prepping the block you should have been informed about the ongoing work in lieu of the condition. Yes it can probably be fixed but you have already spent $ for at this point a junk block that will not provide what you paid for.
     
  17. lippy
    Joined: Sep 27, 2006
    Posts: 5,556

    lippy
    Member
    from Ks

    I can't see the crack in your last pic of the original old photo. Are you sure the crack was there before and not caused by the machine shop when it was sleeved? Is that a new seat? Cause it looks cracked. Lippy
     
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  18. Dyce
    Joined: Sep 12, 2006
    Posts: 1,917

    Dyce
    Member

    After magnafluxing the block, boring the cylinder and grinding the seat I find it very hard to believe any machinist could have missed that crack. I would pressure test it and if it doesn't leak run it. Just because it's not opened up and it would be a bitch to "stitch" through a valve seat and into a cylinder. Pins work great on flat areas but around corners it gets harder (though not impossible). If you do it will need a new valve seat and a cylinder sleeve and machining across the pins might not work the best. I wouldn't trust a machinist that didn't have enough sense to crack check the block in the first place, very unprofessional. I wouldn't trust a pin in a valve seat. Maybe it would be ok with the right pins. I think Goodson sells pins that are made of cast iron but I don't think they all were.
     
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  19. Beanscoot
    Joined: May 14, 2008
    Posts: 2,049

    Beanscoot
    Member

    How about pressure testing it to see if it leaks?
    I've ignored a crack like that on my daily driver car and been lucky.
     
  20. B Ramsey
    Joined: Mar 29, 2009
    Posts: 646

    B Ramsey
    Member

    That was suggested to me also. Seems easy enough.
     
  21. B Ramsey
    Joined: Mar 29, 2009
    Posts: 646

    B Ramsey
    Member

    probably why im hesitant to take it back to that guy.
     
  22. B Ramsey
    Joined: Mar 29, 2009
    Posts: 646

    B Ramsey
    Member

    no Im not sure. the seat is not cracked, probably grease. i would think if the crack was there and leaking, the whole area wouldve been steam cleaned from running? not all built up with carbon?
     
  23. Is there any other machine shops in your area that you could have them look at it? They may be hesitant since they didn't do the original work they may shy away.
     
  24. lippy
    Joined: Sep 27, 2006
    Posts: 5,556

    lippy
    Member
    from Ks

    No I meant in the new photo after machine work the seat looks like it has a crack across it. Sorry for the confusion. Lippy
     
  25. junkman8888
    Joined: Jan 28, 2009
    Posts: 614

    junkman8888
    Member

    B Ramsy; Did a quick search on the "interweb", found there are several cast-iron repair systems available, some even have instructional videos. If the block can be saved you will have to use one of those systems. .
    A couple of you suggested a "J-B Weld" repair. That's not gonna work as the area between the valves and the cylinder bore (that's where the crack is) just happens to be in the combustion chamber. (The engine is a flathead, in case you guys forgot).
    A couple of you recommended "pulling" or "pushing" the cylinder sleeve out plus pulling the valve seat in order to repair the block. In case you didn't know cylinder sleeves and valve seats are always installed with an "interference fit" where the sleeves are left in a freezer overnight, then quickly pressed into the block before they warm up and expand. This means the only way to get that sleeve out is to bore it out. Same thing with valve seats.
    One of you mentioned that the "lock-n-stitch" method will "pull the material together". From what I've seen all of those cast-iron repair systems operate off of a "threaded hole and tapered pin"system. This wedge effect is why I'm not sure you can fix that crack if it goes into the intake port.
    B Ramsy, several of us suggested you need a better machinist, which is the proper advice. Best of luck with saving that engine block.
     
  26. nrgwizard
    Joined: Aug 18, 2006
    Posts: 1,353

    nrgwizard
    Member
    from Minn. uSA

    jm8888;
    You sure on the boring out the only way to get a sleeve or seat out? Iirc, a hot weld from mig will cause the seat to shrink enough to come out, & the same for the sleeve. Works for bearing races n other very tight things.
    BR; Another way to fix the block would be to weld it. There are a few threads on that subject, some hambers said they've done/do it. & of course, the seat n sleeve still need R&R + the machining. Tough situation, hope it works out. At a min, "machinist" owes you a re-do on a better block. Be tough to get that, too, I think.
    Marcus...
     
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