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1970 134 Fhead Head Gasket Replacement

Discussion in 'Early CJ5 and CJ6 Tech' started by jeepstar, Nov 14, 2016.

  1. Nov 27, 2016
    william_cj3b

    william_cj3b 3BOB driver 2019 Sponsor

    Milton, FL
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    Magnetic base drill press. You should be able to rent one locally.
     
  2. Nov 28, 2016
    durangotang

    durangotang Member

    Western CO
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    Where is everyone getting the 4.25" head bolt length? I just did my head gasket with these bolts and they fit just like they are supposed to at 4.5"

    https://www.summitracing.com/parts/arp-hap4500-5

    Kaiser Willys also stocks a 4.5" bolt for the heads.
     
  3. Nov 28, 2016
    PeteL

    PeteL Member 2020 Sponsor 2019 Sponsor

    Hills of NH
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    Last edited: Nov 28, 2016
  4. Nov 28, 2016
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    :oops:

    OK, I know I cut *something* off them to make them the right length.

    H.
     
  5. Nov 28, 2016
    durangotang

    durangotang Member

    Western CO
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  6. Nov 28, 2016
    jeepstar

    jeepstar Well-Known Member 2020 Sponsor

    Sheboygan
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    i stuck a punch down that hole. it goes awhile. that's why I was surprised the bolt length was only 4.25"
     
  7. Nov 28, 2016
    jeepstar

    jeepstar Well-Known Member 2020 Sponsor

    Sheboygan
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    and now im incredibly gunshy about snapping the other bolts. I quit at 60 when I got to bolt 9. still had 6 more bolts to go...thoughts or suggestions?

    I think since I am helicoiling one, why not do them all?
     
    Last edited: Nov 28, 2016
  8. Nov 28, 2016
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    IMHO if it ain't broke don't fix it-

    A lot of extra work for no real gain, 15 times the chance of messing things up, little tiny metal shavings going places they shouldn't.

    As I said before I had a head bolt strip out on me, I helicoiled that one & the rest torqued up just fine.

    H.

    p.s.- put a little sealant on the helicoil when you insert it- I used red threadlocker but anything will do.
     
    73 cj5 likes this.
  9. Nov 28, 2016
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member 2019 Sponsor

    Tri-Cities WA
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    Is your torque wrench accurate? Is there oil in the holes?
     
  10. Nov 28, 2016
    73 cj5

    73 cj5 Not ready for the junkyard yet 2020 Sponsor

    Mississippi
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    I guess while they're out you could chase the threads and get out all the old grime left in the bolt holes while you're back in there to ensure a proper torque.
     
  11. Nov 28, 2016
    jeepstar

    jeepstar Well-Known Member 2020 Sponsor

    Sheboygan
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    i think so. i bought it years ago, and its been sitting on the shelf collecting dust forever. as for oil, I just sprayed on the gasket sealant, same stuff that I sprayed in the head gasket, onto the threaded ends of the bolts.

    my options as I see them:

    1. I get a longer bolt, since I have room for a 5" bolt easily. if it doesn't work, and I blow a head gasket, I have to take it all apart and helicoil it at that time.
    2. I have to helicoil the bolt hole, and to do that I need to change the head gasket anyways, because I cant reuse it.

    im leaning toward option 1, because this isn't a show boat motor. its old and tired. I want to do what's right, but at what cost? a 3 dollar longer bolt, and save the headache of removing the rest of it all.
     
  12. Nov 28, 2016
    jeepstar

    jeepstar Well-Known Member 2020 Sponsor

    Sheboygan
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    I did that before I started. if I take it all apart again, I would.
     
    73 cj5 likes this.
  13. Nov 28, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    If it stripped once it will strip again. I do wonder why it stripped though. I have to ask, do you definitely have the right diameter bolts? What size is the thread chaser?
     
  14. Nov 28, 2016
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    This tells me your bolts aren't long enough. A general rule of thumb is: the bolt should grab a length of threads equal to the width of the bolt (at minimum), when bolt and threads are of similar metals. In this case, your bolt is hardened steel and your threads are cast iron (mush in comparison). The fact that you have less than 1/2" of bolt sticking out before you begin threading tells us that you have less thread length than width.

    When you say your bolts are 4.5", is that the overall bolt length including the head or not counting the head?

    When you have the head off, screw your bolts in by hand until they bottom. This will tell you how much thead depth you have to safely work with. Eliminate the guesswork.
     
  15. Nov 28, 2016
    Focker

    Focker That's what I do, I know things and I fix stuff. Staff Member 2019 Sponsor

    Tri-Cities WA
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    I don't know if there's a Costco near you, but they have a torque wrench analyzer. See if they will let you check yours? After I snapped a bolt I checked all 3 of my Craftsmans and they were all off! :mad:

    And I may be wrong so someone please correct me... I think oily residue will allow you to inadvertently go beyond the torque setting, therefore, risking breaking bolts??
     
  16. Nov 28, 2016
    jeepstar

    jeepstar Well-Known Member 2020 Sponsor

    Sheboygan
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    4.5 is from the underside of the bolt head. the actual length of the rod with the threading on it. not overall length.
     
  17. Nov 28, 2016
    jeepstar

    jeepstar Well-Known Member 2020 Sponsor

    Sheboygan
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    no Costco near me.
     
  18. Nov 28, 2016
    jeepstar

    jeepstar Well-Known Member 2020 Sponsor

    Sheboygan
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    7/16 14
     
  19. Nov 28, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    One thing I haven't seen mentioned is to make sure that the shank of the bolt isn't longer than the head is deep. In other words only threads should protrude if you test fit the length of the bolt through the head.
     
    Twin2 likes this.
  20. Nov 28, 2016
    jeepstar

    jeepstar Well-Known Member 2020 Sponsor

    Sheboygan
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    How deep is that hole? Does it just have some threading material in the block and then it opens up to the inside of the engine bay below it? Because I can fit a 10 inch zip tie down there with no bottoming out in sight.

    My 5 inch bolt could be hand threaded to the stud head and then the same thing happened
     

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