My Rix SA-6 Diesel

[Tracy]

It's ALIVE!!!! She's running perfect, idles down nice.

Cleaned out the fuel tank, messed with the valve, cleaned the filter. Undid the belts so no load and she fired right up.

NOW I hear an ever so faint hiss coming from the 3rd stage piston but it's coming from the fan side. My gauges tell me it's not going back into the 2ns stage. It was worse when it 1st started now it's just really faint. I have to get a hose and hold it up to my ear to hear it... any ideas what I'm in for with that?

Probably an opv. Stretch a water balloon over each one and fire it up. The big balloon is the leaker.

 

[rob.mwpropane]

Probably an opv. Stretch a water balloon over each one and fire it up. The big balloon is the leaker.

No Sir def coming from the back of the piston. It really seems to be less and less each time I fire it up though. She starts every pull, no hesitation.

 

[rob.mwpropane]

It's from here, the back side of the 3rd stage. Is there something I can use to help seal that up. I'm scare to put a dab of oil or something, no idea what that would do..

 

[rob.mwpropane]

Morning Sir. Looking for any ideas you might have about the leak...should I be concerned. It seems to be getting less and less.

Also, wanted to touch base about PP blending. Am I under the right assumption to be really careful when adding O2 to the tanks, but when it comes time to top off it's ok to fill full blast, or should I idle down some? I'm asking about after 100% O2 is already in the tank (no faster than 60psi / minute). I just don't know if there's an issue after that building pressure too fast.

I think that it's ok, as the issue with O2 is going through the valves at the bends?

I'm building a stick, but it won't be ready for prime time by my dive out of NJ Monday. I'm just looking for 28% in my doubles. VERY exciting being able to fill my own tanks!!!!

 

[iain/hsm]

It's from here, the back side of the 3rd stage. Is there something I can use to help seal that up. I'm scare to put a dab of oil or something, no idea what that would do..

View attachment 661738

Er that's the second stage piston side you have in the photo (not the 3rd stage)
Its called "blow by" gas leaking past the ring on the compresion stroke.

Two causes, The ring is worn, or more likely the ring was set in badly in the first place and a small "Leaf"
edge has slipped out of the piston groove and is not allowing a full pressure seal.

The other option is the O-ring ( a big fat "worm" of a thing) under the compression ring has worn on one side or has been scuffed away.

Solution:

Remove the compression ring and either relace it or repair it by cutting a new feather edge on the end of the spiral with a pair of sharp, very sharp scissors.

And while you are at it remove the big fat o-ring (Part 123-313-5) and replace. Cut the old one out by using a pair of needle nose pliers to squeeze up the ring and cut it off without scratching or damaging the bronze piston.
To replace the 0-ring boil it first in a kettle for a few minutes to soften the ring, poke it out and dry it on a paper towel and fit it on the broze piston as soon as possible before it goes hard again.
Then you can use the remaining water in the kettle to make the tea.

Also when fitting it dont twist the thing or roll over one side. The o-ring needs to be centred at the centre line and not twisted or you back to where you started from.

Service 101 to us lot I guess but a whole heap of pain to you lot if you mis fit the assembly.

Also important before you ram the piston into the liner dont shove it in, be gentle turn it slightly and push slowly. That piece of advise was brought to you from the womans section of Cosmopolitan Magazine and reccomended by Mumsnet.

 

[rob.mwpropane]

Er that's the second stage piston side you have in the photo (not the 3rd stage)
Its called "blow by" gas leaking past the ring on the compresion stroke.

Two causes, The ring is worn, or more likely the ring was set in badly in the first place and a small "Leaf"
edge has slipped out of the piston groove and is not allowing a full pressure seal.

The other option is the O-ring ( a big fat "worm" of a thing) under the compression ring has worn on one side or has been scuffed away.

Solution:

Remove the compression ring and either relace it or repair it by cutting a new feather edge on the end of the spiral with a pair of sharp, very sharp scissors.

And while you are at it remove the big fat o-ring (Part 123-313-5) and replace. Cut the old one out by using a pair of needle nose pliers to squeeze up the ring and cut it off without scratching or damaging the bronze piston.
To replace the 0-ring boil it first in a kettle for a few minutes to soften the ring, poke it out and dry it on a paper towel and fit it on the broze piston as soon as possible before it goes hard again.
Then you can use the remaining water in the kettle to make the tea.

Also when fitting it dont twist the thing or roll over one side. The o-ring needs to be centred at the centre line and not twisted or you back to where you started from.

Service 101 to us lot I guess but a whole heap of pain to you lot if you mis fit the assembly.

Also important before you ram the piston into the liner dont shove it in, be gentle turn it slightly and push slowly. That piece of advise was brought to you from the womans section of Cosmopolitan Magazine and reccomended by Mumsnet.

I didn't know you worked for the magazine also

Well it's good it's the 2nd and not the 3rd I guess. Is there any chance that this can work itself out? It seems to be getting to be less and less of a leak... I don't know, wishful thinking maybe?

Edit: just went back and looked, sure enough it's the 2nd stage.

 

[rhwestfall]

Also important before you ram the piston into the liner dont shove it in, be gentle turn it slightly and push slowly. That piece of advise was brought to you from the womans section of Cosmopolitan Magazine and reccomended by Mumsnet.

 

[rob.mwpropane]

Figure I should share the bad along with the good. Today I finally had some time to fill tanks. Everything was going great until around 2200 psi or so I heard a pop and a hiss. Sure enough a BSP to NPT fitting cracked. Kind of scary but it happens. I removed the tower and kept pumping, emailed the company about it. I'm sure they'll stand behind it. I do not believe I tightened it too far, none of my other fittings had any issues even running to 3800 psi, so I think this was just a fluke.

I was able to mix 28% for dives off of NJ on Monday, so that's pretty exciting. Took about 1 hr and 25 minutes to pump ~ 480 cf.

PP blended (nitrox stick not quite done) was shooting for 28% and nailed it thanks to the online Blue Heron Bridge Calculator.

 

[RayfromTX]

If that was mine I would assume that I had overtightened it. Teflon tape makes it easy to over tighten and split fittings. I could be wrong but I try hard to be judicious in my tightening my fittings. I make them tight but I keep in mind that I am stronger than they are once I get a lever working for me.

 

[rob.mwpropane]

If that was mine I would assume that I had overtightened it. Teflon tape makes it easy to over tighten and split fittings. I could be wrong but I try hard to be judicious in my tightening my fittings. I make them tight but I keep in mind that I am stronger than they are once I get a lever working for me.

I won't rule that out entirely, but you can see it's not bottomed out. No different than the other fittings.

Edit: I'm not at all an expert, but putting together (and splitting) tons of fittings and compression fittings over the years. You get that feel like it all of a sudden just gets loose and you know it split. This didn't do that. This popped under pressure around 2200psi. If it was leaking / split before it would 100% have been on me.

In the grand scheme of things it's $6, so not the end of the world.