Stripped a Head Bolt Hole in my old 406

Discussion in 'High Performance Modifications' started by 1980RS, Apr 7, 2021.

  1. 1980RS

    1980RS Veteran Member

    Messages:
    4,973
    Likes Received:
    1,512
    Joined:
    Jun 17, 2006
    Location:
    MN
    Just when I thought I could get this old 406 I ran back in the late 90's going again last night I was putting the heads on, then when torqueing the head bolts the one did not feel right and would not hit 65 lbs. and this just sucks. Took the head off and there already was an insert in there but I don't think I can drill it any further as the hole will be way to close to the cylinder. So here is what I have though of doing so far. First I was thinking of tapping out the hole and getting a Metric bolt to use as they can be from 8.8 to 10.0 and that might work, 2nd and what I have decided to do is I used an ARP head stud from the pack that I am not using and filled the hole and the bolt with JB weld. We will see if it holds after today when it dries, if not then I will try the metric bolt, if that does not work I will tear the engine apart and toss the block.
     
  2. djorgensen3

    djorgensen3 Veteran Member

    Messages:
    734
    Likes Received:
    143
    Joined:
    Oct 15, 2009
    Location:
    Peoria, Az
    Timesert it maybe...
     
    1980RS likes this.
  3. carhead22000

    carhead22000 oldblue

    Messages:
    351
    Likes Received:
    132
    Joined:
    Sep 5, 2011
    Location:
    canada
    i tried with a old 454..i had no luck.it would work and torque down,then after start and retorque it would fail.i,m sure others will chime in.i,d love to save my old 454.goodluck.
     
  4. djorgensen3

    djorgensen3 Veteran Member

    Messages:
    734
    Likes Received:
    143
    Joined:
    Oct 15, 2009
    Location:
    Peoria, Az
    What about the key locking thread inserts? I've never tried them but might be worth looking at.
     
  5. mallard

    mallard Veteran Member

    Messages:
    1,062
    Likes Received:
    296
    Joined:
    Oct 3, 2013
    Location:
    SK, Canada
    Metal fatigue is a beotch. :eek:
     
  6. 1980RS

    1980RS Veteran Member

    Messages:
    4,973
    Likes Received:
    1,512
    Joined:
    Jun 17, 2006
    Location:
    MN
    That idea really looked good until you see the new hole will interfere with where the firing ring of the head gasket seals.
     
  7. djorgensen3

    djorgensen3 Veteran Member

    Messages:
    734
    Likes Received:
    143
    Joined:
    Oct 15, 2009
    Location:
    Peoria, Az
    Well dang it all to heck...
     
    1980RS likes this.
  8. camaro71/holland

    camaro71/holland Veteran Member

    Messages:
    1,467
    Likes Received:
    187
    Joined:
    Aug 27, 2003
    Location:
    The Netherlands
    Does the stud have a (hex) key hole on top? I would use it to apply counterforce when torquening the nut. Might prevent the stud from coming loose.
     
  9. 1980RS

    1980RS Veteran Member

    Messages:
    4,973
    Likes Received:
    1,512
    Joined:
    Jun 17, 2006
    Location:
    MN
    ARP head studs do not have a hex key hole and if one were to do that how would you use the torque wrench on something like that?
     
  10. 70lt1z28

    70lt1z28 Veteran Member Gold Member

    Messages:
    4,168
    Likes Received:
    953
    Joined:
    Oct 3, 1999
    Location:
    Beavercreek, Ohio, USA
    I think the only hope is to use a Keensert type and to leave it slightly raised above the head surface. You may then be able to carefully hand-work the top surface down with a file or similar to level the top with the surrounding surface to give the fire ring on the head gasket something to seal against. Try putting a set screw in the Keensert to support the ID and lightly peening the top of the Keensert in the area of the fire ring to close up the gap. Don't go crazy with this. You are above the top ring land so if the cylinder deforms slightly it should be OK. Finish by running a tap through the Keensert to clean it out a bit. I bet it will work.
     
    Last edited: Apr 8, 2021

Share This Page