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Stripped Threads

Discussion in 'Chevy Trucks' started by BrendonV, Sep 21, 2002.

  1. BrendonV

    BrendonV Junior Member
    Messages: 15

    I have a 1979 Chevy K10 i am rebuliding. I was about to put my vibration damper back on my engine when i noticed the threads were stripped out inside of the crankshaft. I beleive the threads are 7/16. Should i use a tap and die to clean up the threadsm possibly a Heli-Coil???

    any suggestions????????

    thanks BrendonV (16):confused:
  2. Rocky383

    Rocky383 Junior Member
    from alaska
    Messages: 12

    the best solution would be to replace the crank but... otherwise i would probably tap them to 1/2 in. although i dont know what that would do to the balance.
  3. raceman6135

    raceman6135 Member
    Messages: 61

    I've never had that happen on any of my small block Chevrolets, but I had that happen once to a 454 big block. I just used the next size larger fine thread tap, made sure after I tapped the crank that there was enough thread "depth" so that they wouldn't strip again, and went to the bolt supply house and purchased the appropriate grade 8 bolt. Cost me 25 cents for the bolt, I borrowed the tap (so it was free), and I didn't have to try to install 2 or 3 Heli-Coils because the bolt is so long.

  4. ShafferNY

    ShafferNY Junior Member
    Messages: 16

    I just had a similar thing happen to my 350 about two months ago. I was rebuilding the motor and was reassembling everything and didn't notice the treads stripped in the end of my crank until I had the bottom end all buttoned up. The previous owner of the truck stuck the wrong bolt in there and messed up the treads. I ended up tapping it out to a 7/16" course thread, the original, I believe was a 7/16" fine thread.

    I just had to drill it to the right size for the tap and run a tap down it. Everything when back together as normal and I haven't had any problems with it yet. I also used some thread locker on the bolt, just for some piece of mind that it wasn't coming off due to vibration.
  5. BrendonV

    BrendonV Junior Member
    Messages: 15

    hey guys,

    i ended up buying a tapset, then i ran the correct size tap through, then used the di on the bolt and it worked great.
    i was a little nervous about it, but i can breath now.
    thanks for the help