[Mark Scrivener]

My Aster Alisan Shay uses "Graphited Yarn" for piston rings and as a substitute for O rings on the throttle and blower valve. The valves are less of a problem as I could always cut an O-ring grove. But for the pistons one needs a good seal and low drag. Any suggestions? Where does one find "graphited yarn" and what other materials would work for piston rings?

Thanks,
Mark

 

[Mark Scrivener]

Thanks everyone. I think I'll try the Teflon tape route first.....now If I could just get it to stick to the pistons ;-)

 

[Mark Scrivener]

Well, the Teflon tape was easy enough.....but I have a new challenge. The cylinders on the Shay are cast and have brass sleeves. I noticed that the sleeves can slide back and forth and obscure the steam ports. Upon closer inspection I noticed one of the sleeves was copper while the other two were brass, one cylinder has a lip at the top to limit the upward travel of the sleeve, one has a lip at the bottom (but not the top) and the 3rd has no lip top or bottom. Me thinks the sleeves were added by a prior owner as the Aster assembly drawings only show a cast cylinder and does not indicate a sleeve.

So....I now need to find a way to keep the sleeves from obscuring the steam ports. My first thought was to cut longer sleeves that were the proper length and cut a recess for the port, but the sleeves could then rotate and seal off the port. Glue? press fit?

 

[Mark Scrivener]

Interesting....seems there is a loctite compound for everything.

I happened to have some Loctite 515 "gasket maker" compound handy, so I gave it a try. Given this stuff is for IC engine gaskets, it should tolerate heat quite well, and provide enough holding power to keep the sleeves in place. I decided to just keep the sleeves that were already there and see what the engine performance is like before going further. If I decide to make new sleeves or otherwise modify the engine it is a simple process to take the cylinders back off.

Looking at the cylinders, I'm playing with the idea of machining new cylinders from brass. This would allow me to increase the bore and eliminate the sleeve. But for the moment I'm just going to loctite the sleeves and see how she runs.

 

[Mark Scrivener]

Dan,

That thought did occur to me. However, the cylinders are cast (appears to be aluminum). Not sure how well they would hold up.

Mark