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1970 134 Fhead Head Gasket Replacement

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

  1. william_cj3b

    william_cj3b 3BOB driver

    That's a rather large drill! :shock: Rental place didn't have anything smaller?
     
  2. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

  3. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    I brought it home from work
     
  4. Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

    get a piece of 3/8" scrap plate large enough for drill and drill two holes in it . to mount to block . well that's what I would do . done it at work many times
     
  5. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    alright guys. here it goes
    1. new water pump
    2. new thermostat, this one has a weep hole
    3. new 7/16 14 helicoiled engine block bolt hole
    4. new 7lb radiator cap
    5. wider belt on the water pump pulley
    6. new head gasket

    anything else before I begin the reassembly project? I really don't want to go through this again. the weather is in the negatives outside and it takes forever for the shop to heat.

    any good method for removing the spray on head gasket sealant? I was going to use brake parts cleaner, since that works so well for degreasing other automotive projects of mine
     
  6. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Correct length head bolts all round?
     
  7. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    yes. 4.5 for the heads, I don't recall the length of the hidden one in the carburetor hole.
     
  8. Glenn

    Glenn Kinda grumpy old man Staff Member

    2 things: Can you show us a picture of the top of the block before you put the gasket on?
    Make sure none of the bolt shank shows when you stick it through the head.....in other words nothing but threads showing.
     
  9. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    1. you want a pick of the engine block top
    2. you want a pick of the bolt installed through the head, so that you can see how much bolt would be in the block, and confirm only threads stick out below the head?

    is brake parts cleaner an acceptable method to clean the old spray on gasket sealant off of the block and head?
     
  10. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor


    Your call.
    But OEM spec is 4-ΒΌ", not 4.5" (as per your post #67 etc.).

    And, again, the carb bolt should be 1-11/16".
     
  11. Keys5a

    Keys5a Sponsor

    On the length of the bolts, first drop all the bolts in the holes in the head and make sure nothing but threads protrude on the under side. Then, measure how much thread protrudes, and hand thread all of the bolts into the block deck to make sure they don't bottom out before the above measured length is achieved.
    Brake cleaner should be a good cleaner for gasket mating surfaces (head and deck), and I usually use a single-edge razor blade to carefully clean these surfaces.
    -Donny
     
  12. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    they cant bottom out, they go into the water jacket. before I did the helicoil, I tried the bubba method, and got up to a 6" bolt before I realized the length wont matter at all, as there is only so much block material that is threaded.
     
  13. Glenn

    Glenn Kinda grumpy old man Staff Member

    Actually a picture of the head too would be good, but definitely the block. Don't need a bolt picture as long as you know there is nothing but thread showing. Brake cleaner will be fine as long as it works for that.
     
  14. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    the underside of the *head* is what you want a picture of?

    EDIT
     
    Last edited: Dec 19, 2016
  15. Glenn

    Glenn Kinda grumpy old man Staff Member

    Might as well post one, just in case someone sees something wrong. Hopefully we can eliminate you having any more troubles with the head gasket.
     
  16. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    20161219_151724.jpg
    4.5" bolt, and helicoil block hole

    20161219_151740.jpg
     
  17. Glenn

    Glenn Kinda grumpy old man Staff Member

    Thread amount obviously good. The top of the block needs to be as clean and smooth as reasonably possible. You can see the outlines of the headgasket sealing surfaces and those are the most critical of course. Just make sure there are no visible cracks or gouges that would prevent sealing.
     
  18. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Yes. just waiting for the gasket to arrive before i clean the surfaces.

    Should i flush the coolant jacket for any drill debris and the helicoil tang? not sure how important that would be, but dont want to wreck my 600 radiator doing this project next. talk about project creep!
     
  19. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Especially just where the cylinders almost come together.
     
  20. PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    You could fish with a magnet-stick, but you'd probably get a lot of rust flakes too, and then that would lead to the next bunch of worries.