cracked block: to weld or not to weld?

Discussion in ''Da Nailhead' started by supersteve, Sep 4, 2016.

  1. supersteve

    supersteve Member

    I have a feeling I know what the answer is but I'll ask anyway. I recently acquired a 401 with cracks on the side of the block. As in several cracks on each side. Given the fact that this block will also need sleeved in one or two holes, does this sound like it's time for a new block? I could possibly save money by having friends with welding experience help me with the crack repair, so this would save money there, but my fear is that more cracks might appear in the future. Plus I don't know if anyone even does block sleeving anymore so this could be moot.
  2. Golden Oldie 65

    Golden Oldie 65 Well-Known Member

    Scrap it. You would have a fortune in it by the time all that was done. Those engines are still out there for sale, it shouldn't be huge problem finding a good core. Post an ad in the 'parts wanted' section here, I'll bet you'll find one in a few days or less.
  3. Ziggy

    Ziggy Well-Known Member

    Replace the block unless you are keeping matching numbers.
  4. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Sleeving isn't a problem, any machine shop that bores blocks should know how to install a sleeve.

    Need to see pictures of the crack to accurately suggest to fix or not to fix.

    There are non-welding techniques that can repair cracks in a block that are relatively inexpensive if you do the work yourself but can be time consuming.


  5. supersteve

    supersteve Member

    If I posted pictures of this, the moderators would probably ban me, it's that bad.:eek2: I forgot to mention that there is also a dime-sized hole as part of these cracks (no evidence of catastrophic failure, just a result of the over enthusiastic grinding from the yay-hoo who ground on this before slathering JB Weld on it:Dou:). A couple of the cracks extend up into one of the head bolt bosses into the threads. I did check into the Lock-n-stitch method of crack repair but this would never work since a lot of the cracking is in curved surfaces.
    Yeah, this block is done, time to put it in a shoe box and bury it in the backyard.

    I was trying to save this because I hate to waste anything. Oddly enough, that's how I ended up with this motor: I found it in a 62 Wildcat in a junk yard and I didn't want to see it get scrapped, so i grabbed it, the tranny, driveshaft, and complete rear end for some unknown future project.

    Thanks, guys. Off to the parts wanted section.
  6. 8ad-f85

    8ad-f85 Well-Known Member

    Places that deal daily with industrial engines (meaning huge and expensive engines) repair this stuff easily.
    A buddy that has experience welding is not likely even close to being able to do this one sufficiently, it's more about the process.
    Any shop should be able to handle sleeving and there are lock and stitch methods able to safely replace large windowed sections of a block.'s up to you.
    I'd keep it for myself as I do this stuff, but I would still recommend replacement as it is certain to cost less.
  7. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    I'll have to concur after reading this description that the block is toast! Unless it is only cracked on one side, then you can make it a 4 cylinder if you really think you need to save it from being scrapped. :rolleyes: GL

  8. alan

    alan High-tech Dinosaur

    Or fill it full of block fill and run it on alky in a front engine dragster! :3gears:

    (That would be cool)
  9. 8ad-f85

    8ad-f85 Well-Known Member

    ^^ Likes that idea.

    It's quite just don't want to see the invoice for it! :grin::shock::shock:
  10. supersteve

    supersteve Member

    You guys are missing the obvious alternative use.

  11. 8ad-f85

    8ad-f85 Well-Known Member

    That would be an insult to some of our trades or skill levels.
  12. wilber

    wilber Well-Known Member

    I agree with that one.

  13. Buddyboy456

    Buddyboy456 Active Member

  14. 66electrafied

    66electrafied Just tossing in my nickel's worth

    Had the same issue with my 401. Someone had stitched, brazed and defconned the whole works together. It didn't leak, but it sure was warped. And there were new cracks forming, just when I lifted it out and started stripping it down.

    The block was toast, simple as that. There's no point throwing good money after bad into a bad block. Find another block; you'll be a lot happier once you do.
  15. supersteve

    supersteve Member

    No insult intended, just having a bit of fun with my own misfortune.:beers2:

    Shame on you. I love my 401 and would never toss it into the water. Yet.


    Yeah, that's what I'm afraid of. These cracks had been vee'd out with a grinder, but I noticed yet another small, unground one that evidently had started after the grinding.
    Who knows when this would end.
  16. 8ad-f85

    8ad-f85 Well-Known Member

    Part of what makes it so costly for a QUALIFIED rebuilder able to handle the very expensive blocks being repaired is that major areas pinned or oven brazed castings can get heavily warped, requiring the re-machining of many of the features of the casting.
    This often means more than main line boring, cam tunnel boring and decking, and may extend to other rudimentary cutting ops.
    The shop determines which areas may be brass brazed vs. pinned vs. electrically melted vs. re-poured while red hot, and what substructure may be reinforced.
    This is what makes a major structural repair by a welding buddy or lesser experienced shop a great risk.
    It CAN easily be fixed, but...probably much cheaper to replace.

    I know there is an industrial engine company near you.
  17. Bib Overhalls

    Bib Overhalls Well-Known Member

    I put a wanted ad for a Buick Nailhead up on Craigslist (in the auto parts section) and had a 66 401 sitting in my shop 4 days later. Paid $400.
  18. doc

    doc Well-Known Member

    just replace it.... easier, less costly,,,, use the cracked one to section and learn about nailheads....
  19. Tommy Sawyer

    Tommy Sawyer New Member

    I have a good 401 block out of a 64 Riv that I would let go of cheap if you are interested. Was running when pulled apart and it does have one sleeve
  20. supersteve

    supersteve Member

    Do you have any pictures, good sir?
    Is it standard bore? No cracks?
    What is your location?

Share This Page