Slant 6 Steel Head Gasket.......

Slant 6 Engines

  1. RustyRatRod

    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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    So @pishta was wondering about the OEM slant 6 steel shim head gasket thicknesses. I have the answers. I recently acquired an NOS steel shim gasket from @volaredon, thank you , Don. I already had an old one I saved. So here is what I found out.
    First, I measured the old one in an area that was not embossed, but just flat. As you see, I got .015".
    DSCF1604.JPG
    Next, I measured the embossed fire ring on the old gasket. As you can see here, I got about .019".
    DSCF1605.JPG
    Next, I measured the new head gasket in the same unembossed spot I did the old one. As you can see, I got the same .015" that the old gasket measured.
    DSCF1606.JPG
    Finally, I measured the uncompressed fire ring on the new gasket. You can see I came up with about .040". Both the old and new gaskets measured the same gasket bore diameter of 3.560".
    DSCF1607.JPG
     
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    • pishta

      pishta I know I'm right....

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      Holy Frijole! Let me measure mine....
      .020 on flat spot (dirty) and .027 across compressed fire ring. So those bade boys are .040 uncompressed! With the 70 ft/lbs (dry) torque on those bolts they have a clamping force of 9,550 lbs. If you lube the bolts and torque them to 70, that increases the clamping load to ~11,700 lbs....!
      I wonder if you could take a .012 stainless wire under those fire rings and beat a new .040 onto them with a rubber mallet? Or just run it again with some copper spray.
       
    • RustyRatRod

      RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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      Does RTV count as lube? I use it on every single head bolt I install.
       
    • RustyRatRod

      RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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      I would also BET that since the embossed areas of the old gasket are STILL thicker than the unembossed areas, if one was cleaned really well and copper coated really good that it would seal again. I just bet. Especially on one that didn't have a ton of cylinder pressure.
       
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      • pishta

        pishta I know I'm right....

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        • pishta

          pishta I know I'm right....

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          @RustyRatRod Check Vixen under her head with a .015 feeler gauge. Maybe that's where it stops.
           
        • RustyRatRod

          RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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          I can do that on the 170. The 225 in it now has a composition gasket. I will report back shortly.
           
        • RustyRatRod

          RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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          What's your thinkin? That the embossed areas rebound the .004"? You might be onto somethin.
           
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          • MarPar

            MarPar Young Troubadour FABO Gold Member

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            panda popcorn.gif
             
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            • RustyRatRod

              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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              The .015" won't go in anywhere and it stands to reason why. There's nowhere for it to go. The head gasket takes up the entire outside perimeter of the head, so it ain't gonna fit. lol
               
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              • pishta

                pishta I know I'm right....

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                Doh! Question would be is the head off the block .015 or .019-.027..we may never know unless you can get a .002 between the gasket and the iron (.019 crush limit) ? Interesting observation.....
                 
              • Killer6

                Killer6 Well-Known Member

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                Yes, the embossed areas are rebounding when unloaded. Bill Travato glues a copper wire "fire-ring" to used shim gaskets & reuses them without issue, not sure what gauge wire is working for Him on that.
                 
              • RustyRatRod

                RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                @pishta I also noticed something else. This should put to bed which way the gaskets install. They install "upside down" compared to what "I" would normally do. Clearly they are stamped "TOP" on the negative embossed side. I am pretty sure they'd work either way, but the factory wanted the positive emboss toward the block, for whatever reason.
                DSCF1620.JPG
                DSCF1619.JPG
                 
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                • pishta

                  pishta I know I'm right....

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                  Copper wire in the ditch and mount them back up. copper is soft enough to mold. Heck...I'd try it but I'm already mounted up. Ill file that under "it may work"
                   
                • Ironracer

                  Ironracer Gearhead

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                  I miss those lil things... /6 cars for almost nothing, damn near mint. Always ran good.
                   
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