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

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RustyRatRod

RustyRatRod

I was born on a Monday. Not last Monday.
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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
 
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.
 
pishta said:
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....!
Click to expand...
Does RTV count as lube? I use it on every single head bolt I install.
 
pishta said:
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.
Click to expand...

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.
 
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
 
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.....
 
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.
 
@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
 
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"
 
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