Yong Heng piston rings

Still subzero at my place and last night was snowing, but can't wait to start with my season.

Today out of boredom I pulled out one of my tanks I think it is below 250 bars, let me refill if any actions come up soon in the backyard :) .

And my YH didn't want to build up a pressure. Again ... It was sitting since about mid Sep, I was away for three months to EU trips and got back home when winter was already on the go.

The first stage steel tubes cold on touch, the second stage is burning. Aaaha...
Disassembled the YH first and second stage, I am noticing oil in cylinder walls, pulled out the piston assembly, and the first stage piston rings are shiny... gone...the second stage rings look OK.

I just checked my aliexpress purchase history, last time I ordered a full cylinder + piston all in a kit, in March last year. Prior that somewhere in 2021. I think it is not so bad for total of 64 hrs. Also, may be a good entertainment tinkering with.
In my crate I have two (didn't throw them out) full cylinder+piston assemblies, all worn the piston rings. I think both rings, the lower lubing and the two upper compression rings the edges shiny.

Anybody come up with a source for first stage piston rings only? I may order a full bag of those.

I don't mind buying the piston+crank kit for $20, or maybe two, but when I know the rings goes first.....

Also, I trust myself most how to mount rings on pistons ;)

Screenshot 2022-06-24 at 21-37-30 YONGHENG PCP Cylinder Piston Rod High Pressure Air Pump Comp...png
 
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:)
Last night I ordered two piston assemblies from aliexpress, $44 USD shipping included ETA about two weeks.
Today morning I was moving things around in my hobbies locker, pulled out the YH crate, and I found two BNIB piston assemblies I ordered probably last year.... I completely forgot about these, I could have saved myself the greenies.
So, I would expect that I am set for a while :)
 
Tinkering out laud now.
If my memory serves me well every time I had to replace the second stage piston because of a worn rings... this green o-ring was broken.
If that green o-ring is gone, the back pressure puts an extra stress on the piston "plastic" rings.

20220810_133743.jpg


I need to figure some other material that is less Temp vulnerable.
I have nomore of these in green, I just put a black NBR70 for now...
 
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Tinkering out laud now.
If my memory serves me well every time I had to replace the pistons because of a worn rings... this green o-ring was broken.
If that green o-ring is gone, the back pressure puts an extra stress on the piston rings.

View attachment 549469

I need to figure some other material that is less Temp vulnerable.
I have nomore of these in green, I just put a black NBR70 for now...



Where is that part found?