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Level It? Valve Cover Bolt Holes

Discussion in 'Intermediate CJ-5 and CJ-6 Tech' started by Chuck Tom, Nov 16, 2018.

  1. Nov 16, 2018
    Chuck Tom

    Chuck Tom New Member

    Arizona
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    I’ve cleaned up the valve cover for the 74’ CJ5 AMC 258 l6 and was wondering in this picture I have attached. Does this bolt hole need to be flattened? I’ve read in other threads that this should be done to improve the seal. Thanks for your help guys!

    ***edit***. I added an additional picture to show the worst one, in my opinion
     

    Attached Files:

  2. Nov 16, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    Yes, definitely. The entire sealing surface should be on the same plane.

    Get a block of steel and a little hammer and tap-tap-tap until the whole gasket plane is flat.
     
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  3. Nov 16, 2018
    TIm E

    TIm E Sponsor Sponsor

    NW Arkansas
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    X2 On any kind of cover or pan like that where the bolt pressure distorts the flange around the hole, good to flatten the gasket surface. Also good to not over torque the bolts while installing.
     
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  4. Nov 16, 2018
    Chuck Tom

    Chuck Tom New Member

    Arizona
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    I’ve read somewhere that using a nut driver tightened by hand is sufficient torque. Is there any validity in that statement?
     
  5. Nov 16, 2018
    TIm E

    TIm E Sponsor Sponsor

    NW Arkansas
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    Perhaps about as tight as you can with a nut driver may be about right (depending on the size/strength of your meat hooks). It is kind of a "feel" thing for me, I'd call it medium tight. You want it snug, but not so tight it distorts the flange. Another visual check is that the gasket should look relatively the same thickness (side profile) when the bolts are tightened, not crushed thin where the bolts are.
     
  6. Nov 16, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    There is a spec in the TSM. You'll need an inch-pound torque wrench. I'ds guess about 40 in-lbs. Not much. I use a 1/4" ratchet in my palm.
     
  7. Dec 2, 2018
    Jester

    Jester New Member

    Jefferson Oregon
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    1/4-20 bolt torque should be 12-14 lbs.
     
  8. Dec 2, 2018
    PeteL

    PeteL Member Sponsor

    Hills of NH
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    I think it's less about the bolt and more about the gasket.

    I'd tighten it very gently and evenly. If it leaks tighten it a tiny bit more.
     
  9. Dec 2, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    Follow the TSM spec, not the general spec for a 1/4" bolt. That much torque will definitely damage the valve cover.

    upload_2018-12-2_10-17-28.png

    12 inch-lb per foot-lb. Jester's suggested torque for a 1/4" bolt is three times the force specified by the TSM, assuming he means ft-lbs. This will damage the valve cover by bending it, and it will leak. It may even ruin the valve cover, depending on whether the owner can straighten the bending done by the bolt.

    If you assemble and torque to spec, and it leaks, do not tighten more. This will damage the valve cover. Remove and straighten the valve cover, and try it again. Tighten them all a little, then a bit more, and a bit more, till you reach the spec. Note these valve covers even leaked from the factory. Mys factory-fresh 1975 with a 258 seeped a tiny bit, and left a dusty stain on the engine side. But it did not drip. Don't be greedy - if the cover does not drip, declare victory.
     

    Attached Files:

    Last edited: Dec 2, 2018
  10. Dec 2, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
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    I have one of these, and it's good for setting preload on bearings and such. It would also work fine for tightening the valve cover screws.
    https://www.amazon.com/Neiko-03727A...3765365&sr=8-5&keywords=inch-lb+torque+wrench

    If you are not certain, get the tool. Once you get the feel for the proper tightness, you can do them from your memory of how tight they should be. I know the mechanics at the dealership would tighten by hand, but they had experience with how tight the bolts should feel. Quoting one, his "calibrated forearm."
     
  11. Dec 2, 2018
    Jester

    Jester New Member

    Jefferson Oregon
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    Interesting. I use this same torque spec; yes that is foot pounds, on every valve cover of every tractor and combine I work on with a stamped steel vavle cover (since that is mostly what John Deere used on older equipment) and have NEVER had one be damaged or leak. Then again, John Deere also has a very unique washer probably for that very reason.
    Without knowing the grade of the bolt, perhaps, I over stated the torque needed. A grade 2 specs @ 4 foot-lb., grade 5 @ 6.5 foot-lb. and grade 8 specs a@ 9.
    I use 12 because the last one I installed @ 6 foot-lbs (per deere) came loose and started the combine on fire. Luckily it was extinguished without serious damage.

    My appoligies for my previous reply. I realize I don't know everything, just what works on other pieces of equipment I work on every day.

    Good luck
    Jes
     
    Last edited: Dec 2, 2018

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