Teflon lube will be the first to try 
Will a lube stay put?
No it will not last forever but I think it will be better then liquid lubricants in this aplication. Anyway any lube or coating will weal out eventually. Idea behind stainless steel piston is that it will have less friction then original aluminium piston to start with.
Aluminium to aluminium sliding friction coefficient is ~ 1,4 while aluminium to stainless steel is only ~0,5
The lower friction is good, but the big issue is probably galling. Aluminum to aluminum will gall something awful. I donât know about SS to aluminum. Is there any way you could press a brass sleeve into the cylinder? Polish up the outside of the SS piston, and it should slide smoothly forever.
Alternatively, you could apply the same sort of teflon treatment used on piston skirts in Nikasil engines. I think the things might even be a peel-and-stick thing, I dunno. If so, you could get some from a Chevy and just cut out pieces to wrap around that little AAV piston. Of course, youâd need to machine the piston a bit smaller to allow for the thickness of the teflon.
I think nikasil coating is electroplated
I think it is possible but first I will polish the piston and see how it works with aluminium body. I bet it will be much better then original.
The nikasil coating to the cylinder is plated or something. Iâm talking about whatâs done to the pistons, which involves a patch of teflon on each side of the skirt. Itâs apparently what keeps the skirt from galling the nikasil liner.
https://www.highpowermedia.com/blog/3126/piston-skirt-coatings
Hereâs a pic of a piston with the skirt treatment, in this case in a pattern with the manufacturerâs logo!
What if one press fitted a machined Teflon sleeve to the piston, or even did the piston entirely out of Teflon ? Just a thoughtâŚ
Donât know how the heat would effect it though.
I made a bearing for my Record Player, high polished Stainless Steel axle on a Brass bearing with a Teflon sleeve insert.
It worked very well, has Zero Tolerances, Zero Noise (very important) and almost Zero Friction.
Nevertheless, when I rebuilt my Auxiliary Air Valve Iâve just sanded and polished the aluminium piston to give it some more clearance and it works fine 13 years sinceâŚ!
Aristides
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Thermal bulbs is not as much of a problem as the âoily shâŚthat builds up in the cylinder wallsâŚ.I always hone both the piston and sleeveâŚif you really want to do something important, make new pistons from Delrin or? so they donât gall
and hang up. Best, JW
Mail](https://go.microsoft.com/fwlink/?LinkId=550986) for Windows 10
Just finished rebuilding another small lot of AAVâs.
All cleaned and assembled with new internals: new thermal bulbs, new polished stainless steel pistons, new stainless steel springs.
Ready to be shipped 
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Incredible work. Did you fab all new cylinders? I canât imagine the originals cleaned up that well.
Yes. In this lot all cylinders are new as well. Some of them where way too far gone due to internal rust and oxidation so I made a new ones. Here only the body was cleaned and reused.
Before picture:
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Hi John, very impressing work. I just found it today.
I´d like to repair my own valve (XJ81). Do you still provide parts for the work.
I would be happy to her from you. I am living in Germany.
KInd regards Hubert
Yes I still do rebuild them and I can offer rebuild kit if you prefer to rebuild it yourself. Let me know your email or send me a message to this email for more details: jag.improver@gmail.com
Hey John,
What do you recommend on the idle bolt threads so they donât leak air, but can still be turned easily for adjustment?
A bit of Teflon tape I think will work great, but It does not really matter if there is a tiny leak from the screw.