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258 Valve Cover Leak

Discussion in 'Intermediate CJ-5/6/7/8' started by ndh87, Jun 12, 2023.

  1. Jun 12, 2023
    ndh87

    ndh87 Does it run?

    Middleburg, VA
    Joined:
    Jun 3, 2007
    Messages:
    34
    Ive got a 84 date coded 258 in my intermediate 1974 cj5. The plastic valve cover doesnt seal on the passenger side. I can grab the gasket and move it with everything tightened down. What metal valve cover can i replace it with?
     

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    Last edited: Jun 12, 2023
    ndh87, Jun 12, 2023
    #1
  2. Jun 12, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
    Messages:
    5,667
    edit- maybe posted incorrect info....
     
    FinoCJ, Jun 12, 2023
    #2
  3. Jun 12, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
    Messages:
    5,667
    ok - I wasn't totally wrong in my first post...there are quite a few metal valve cover options out there for the 258, but there is an issue with the mount/bolt pattern in some cases. I had this issue with my 84cj7 258 many years ago, and the metal aftermarket options required drilling and tapping the heads. I don't know if there are different sets of heads that do match the pattern or what not. Just something to be aware of. Maybe someone on here knows the 258 details. I ended up going with a new plastic cover (after cracking the original one overtightening it) and a neoprene gasket with a smear of RTV. Still seeped, but not a leak.
    here is the classic aluminum aftermarket cover (not necessarily the best price) - but again, check the bolt pattern and if you are up for drilling and tapping the heads:
    https://www.quadratec.com/products/..._Yb0yqxB4OCw-r02tJu4eEfuiBRGOKEBoCfuwQAvD_BwE

    Read the reviews here for some discussion on the drilling and tapping:
    https://www.summitracing.com/parts/omx-1740108/make/jeep
     
    FinoCJ, Jun 12, 2023
    #3
    vtxtasy likes this.
  4. Jun 12, 2023
    ndh87

    ndh87 Does it run?

    Middleburg, VA
    Joined:
    Jun 3, 2007
    Messages:
    34
    My heads are setup with the clamp type bolts on the driver side, 1/4x20 bolts, 1 front and back and i think 3 on the passenger side, doesnt have the center bolts that run through the top of the cover.
     
    ndh87, Jun 12, 2023
    #4
  5. Jun 12, 2023
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
    Messages:
    5,667
    I think all the metal ones have those center mounts that bridge over the rocker arms etc.....believe it has the correct edge/flange mount pattern, but its the center bridge mounts that require some modifications....
    [​IMG]
     
    FinoCJ, Jun 12, 2023
    #5
  6. Jun 12, 2023
    AndyinTexas

    AndyinTexas Member

    central Texas
    Joined:
    Jan 30, 2023
    Messages:
    68
    I just did this swap a couple months ago on my `85 and used the exact cover above.

    The plastic cover has two rocker arm bridges with studs that go through the cover for hold downs. Those are eliminated for the aluminum cover swap; you can buy two new bridges without the studs (cheap, got mine at O'Reilly's) or just saw the studs off. On the passenger side, and front/back, there are perimeter bolts that are 1/4". On the driver side, two untapped holes that correspond to nubs on the plastic cover for locating purposes. The factory used a sort of large washer on head bolt stands as hold downs on the driver side edge. You can't use them with the aluminum cover so you tap the locator holes to 5/16". Be aware the holes are not deep, even with a bottom tap you can only get a few threads, so I recommend drilling them deeper. Is there water under there? Probably, so don't get carried away and drill very deep. And lastly, with the new cover so close to the firewall, it's nearly impossible to get to that rear bolt. If you're determined you can get done with much cussing, or just leave it out.

    PITA for what should be a simple swap, but for me it was worth it.
    BTW the pic above shows the bridges with studs, not sure why because you can see there are no holes in the cover for them. You need bridges without studs for the aluminum cover.
    Last edit, I think, the included gasket is nice and thick, however, narrow in several spots. If it slips just a little on installation, you get a massive leak. I used a cork Fel-Pro, it's not as thick, but wider in critical areas than the other and works perfect for me.
     
    Last edited: Jun 12, 2023
    AndyinTexas, Jun 12, 2023
    #6
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