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The factory gasket materials are great but in my experience, they just do not seal! At least on my single turbo applications. This is verified with multiple smoke tests over the years on multiple manifolds and factory new gaskets. 100% fresh professionally machined flat manifold surfaces. They just do not seal.
The closest to a 100% seal I have gotten with the factory gaskets was with the "Rob Dahm" method. Felt gross and dumb for even doing it but I had to give it a try. You would think fresh gaskets with 100% flat surfaces would seal but Rob certainly knows what he is doing. From my own testing his method leaks a ton less then factory gaskets alone but still leaks and does not last.
For anyone that cares here is a parts list of what I use for a 100% exhaust seal. I am not saying this is the best method and probably overkill but this is what works for me after a ton of trial and error. I'll post a pic of how I test if anyone is curious.
^^just pointing out that the nuts on the Full Race stud kit are not Inconel, but A4-70 material with silver plating. Which is T316L austenitic stainless steel having a 70,000 psi tensile strength.
Even the A286 studs aren’t actually Inconel, but considered a similar superalloy material that’s a cost-effective alternative.
So only the gasket appears to be Inconel material.
However, McMaster-Carr sells M10x1.5 silver-plated A286 superalloy heavy duty flanged nuts, but only in a 12-point hex configuration @ ~$8 each that can be used without modification on the Mazda exhaust studs.
^^just pointing out that the nuts on the Full Race stud kit are not Inconel, but A4-70 material with silver plating. Which is T316L austenitic stainless steel having a 70,000 psi tensile strength.
Even the A286 studs aren’t actually Inconel, but considered a similar superalloy material that’s a cost-effective alternative.
So only the gasket appears to be Inconel material.
However, McMaster-Carr sells M10x1.5 silver-plated A286 superalloy heavy duty flanged nuts, but only in a 12-point hex configuration @ ~$8 each that can be used without modification on the Mazda exhaust studs.
on that note the copper nuts aren't copper. they are like a hard cheese with a copper coating.
they do have a mechanical lock, but its not as robust as Mazda/Kia so it doesn't back off. ive re-used mine a few times now.
so slight disappointment, but the price is right, and its a 14mm hex like it should be
on that note the copper nuts aren't copper. they are like a hard cheese with a copper coating.
they do have a mechanical lock, but its not as robust as Mazda/Kia so it doesn't back off. ive re-used mine a few times now.
so slight disappointment, but the price is right, and its a 14mm hex like it should be
Yes, I avoid the lock nuts for that reason as well. What I use instead, despite any nut coating, is the high grade, high temp Nickel anti-seize. Because not only does it prevent corrosion and increases ease of removal down the road, it’s thick and becomes thicker with heat to resist the nut from backing off due to vibration. The typical auto store Copper based anti-seize will simply melt off and become useless.
A 12mm 12-pt hex is stronger than a 14mn 6-pt hex. Again, it’s used specifically for high torque fastening. Not that 30 ft-lbs is all that high. It’s a non-issue.
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A 12mm 12-pt hex is stronger than a 14mn 6-pt hex. Again, it’s used specifically for high torque fastening. Not that 30 ft-lbs is all that high. It’s a non-issue.
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