Adjusting my 2nd stage - Help!

[KatherineLee]

So I tried to practice and followed my repair manual (Alpha 8) to assemble the valve body and I think I did something wrong. I had the nylon lock nut on the poppet to expose 2-3 threads as instructed to set the lever height and then adjusted the orifice for cracking pressure. My problem was when I adjusted the orifice just a tiny bit to stop free flow, the lever arm started to come loose. What did I do wrong here? If I thread in the nylon nut a thread or two more to tighten the lever arm again but then this would be different from instructions. Is the 2-3 thread rule just an estimation and it's ok if I had 4 threads or so? I'm using a screwdriver to adjust orifice and a sink of water for
cracking pressure. No instrument but I do have proper tools so that I don't damage parts.

Any help is greatly appreciated. Thanks!!!

 

[muddiver]

I was wondering the same thing about my Kirby Morgan regulator, but it seems that the lever arm will be loose when adjusted correctely. The diaphragm should not rest on or deptess the lever arm in nutral pressure position or it will free flow constantly.

Also, you did not tell use the brand and model of regulator you are working on.

 

[Jim Lapenta]

She is using an Oceanic Alpha 8. I hope that you are using a new nut. The nylon locknuts are not meant to be reused. And I know it says 2-3 threads but depending on the the poppet there were some that were a thread or two long and are a biatch to adjust using the recommended length. I always start with 1 1/2- 2 threads showing and go from there so yes you may have an extra thread or two showing. It is better to have to tighten than loosen. Again this is due to the fact that you should not reuse the lock nut and washer. Throw em away and replace with the new ones. One thing with nylon nuts is that once they are used they will not retighten properly and may come loose. And be sure the washer is on there with the nut. And I would also caution against using the screw driver as you have no way to breath the reg while adjusting. An inline tool is worth the investment. If you adjusted too much with the nut not on far enough you may cut the seat too deeply. And a screwdriver does not give the same "feel" as a proper tool.

 

[LeadTurn_SD]

So I tried to practice and followed my repair manual (Alpha 8) to assemble the valve body and I think I did something wrong. I had the nylon lock nut on the poppet to expose 2-3 threads as instructed to set the lever height and then adjusted the orifice for cracking pressure. My problem was when I adjusted the orifice just a tiny bit to stop free flow, the lever arm started to come loose. What did I do wrong here? If I thread in the nylon nut a thread or two more to tighten the lever arm again but then this would be different from instructions. Is the 2-3 thread rule just an estimation and it's ok if I had 4 threads or so? I'm using a screwdriver to adjust orifice and a sink of water for
cracking pressure. No instrument but I do have proper tools so that I don't damage parts.

Any help is greatly appreciated. Thanks!!!

Here is a long answer first:

I believe your Oceanic Alpha 8 is a two-adjustment, "classic" unbalanced downstream design.... the two adjustments are orifice depth and lever height.

With this type of 2nd, the typical adjustment sequence is to "rough-set" the lever height (that is what tightening the nylock nut until 3 threads show is doing), then adjust at the orifice..... then, re-adjust the lever height!

Lever height and orifice adjustment are linked. As you screw the orifice in, it presses on the soft seat, moving the poppet, and moving the lever down. This is the "loosening" you saw.

It is a balancing act getting the adjustment right.... the goal is to have full lever travel & minimal spring tension for best breathing performance, but a reliable seal so the reg does not freeflow.

One of the very best things you can do when working on a classic downstream 2nd stage is to make careful notes BEFORE you completely take it apart.... note the number of threads showing, measure the lever height relative to the rim of the case, and note the number of turns the orifice was adjusted to (by pressing down on the demand lever and screwing the orifice in until it stops, while counting the number of turns it took to reach the end...).

If you take careful notes, when you reassemble the reg the whole tuning process goes much faster, as you can set orifice depth and lever height to pretty close to where they need to be, then begin fine-tuning....

Anyway, what you see happening is when you tighten the orifice is the lever drops, and you need to then tighten the nylock nut slightly to return it to its correct height...

Hope this makes sense. Most of my 2nd stages are Mares models, which are classic downstream designs similar to your 2nd.

One huge caution here.... if you incorrectly install the lever, it CAN fall off during use, so make very sure you've done this correctly.... a lever falling off results in instant failure of the 2nd stage to provide air (you'll think you've instantly gone OOA).... but it is pretty easy to service this type of 2nd stage, so with a little attention to detail it should be no problem

Best wishes.

 

[redacted]

If by "lever arm started to come loose" you mean that it went from no play to a little play, that is exactly what you should expect. "Too loose" OTOH is when cracking pressure is adjusted correctly and you shake the reg with air on and hear the lever rattle. If it breaths good and the lever does not rattle, you should be fine.

Although most (maybe all) mfgrs recommend a new nyloc nut, I have had no problem reusing them at least once or twice. Check to make sure the nylon is still grabbing the threads. And, you can add a dab of Loctite if you are not sure. If it does not hold well, performance will degrade rapidly well before that nut becomes dangerously loose. Also, any time you are turning the orifice adjustment, the purge should be depressed to prevent the knife edge from cutting the seat. While an inline adjusting tool will made adjustment go much faster, the end result can be the same without it.

 

[halocline]

Leadturn's explanation is excellent. You need to first try installing the diaphragm and cover, and then you can see if the lever is too low. (rattling like awap says and/or the purge is not very responsive) Then you raise the lever by tightening the nyloc nut a little. You don't want it tight, just a small amount of play. If it's too tight the diaphragm will push it down a bit and you'll be back to freeflow.

If the nyloc nut seems a little loose when you're done, take some nail polish and put a drop right on the nut where the threads from the seat carrier emerge. That's what the doublehose guys do; they have a regular nut holding the seat carrier in place.

Have fun!

 

[KatherineLee]

Thank you guys! I practiced again tonight for a few hours and I think I'm getting better. I adjusted the orifice and nylon nut as many times as needed to stop freeflow and to set proper lever height My lever tip is slightly below diaphragm and no rattling. I also made sure that it wasn't too loose (with little play) and that it had a good range of travel. All of the above were done with air turned on. I'm using a new nut and initially I thought I must follow the 2-3 thread rule strictly but after your explanations it's much clearer now. I enjoyed it

 

[tfsails]

Some manufacturers dictate that the demand lever rattle some when the second stage is shaken. Others mandate it not rattle at all. Oceanic is one of those. Here's a quick down-and-dirty for unbalanced second stages: if you can purge it and it breathes ok and doesn't free-flow then you're damn close to where you need to be for your final adjustment. I've run across Oceanic and Aeris second stages where no matter how hard you try you can't get it properly adjusted without some demand lever rattle. Whether or not the rattle is present is my tertiary consideration when tuning those second stages behind ease of breathing and free-flow.