Phoenix Pin Length

[Bryan]

If you are doing the assembly, setup and install of the Phoenix nozzle yourself I would recommend the overall length of the pin to be 1.30 to 1.31 inches for proper operation.

When you trim the pin be sure the end you cut is square and the sharp edge is smoothed down slightly. Measure twice.....Cut once.....Take your time.

[1969ivan1]

Better yet, let Bryan do it!

[JES]

Better yet, let Bryan do it!

Amen!

[Drado]

Is this the recommended pin length for the Mod I or Mod II nozzles?

I asked Luis what the recommendations were, and he said that the mod II nozzles had shorter pins. The 2 recommendations he gave were:

1. Gap between mushroom and nozzle face should be between 0.03" and 0.04", but closer to 0.03" would be better, because...
2. The mushroom should reach the face of the nozzle without bottoming out inside the nozzle.

The larger the gap, the more the seat can open.

I'm bringing this up because I got my Phoenix today and took some measurements:

Stock length of the pin was around 1.3" I thought I wouldn't need to trim it.



Upon checking the gap, it seemed a bit large. Around 0.062"


Verifying against the light, I found that the internals were bottoming out before the mushroom reached the nozzle face:


So, I took 0.02 inches off the pin (down to 1.28") leaving me with the "upper" gap limit of 0.04"


This was enough for the mushroom to reach the face of the nozzle.

After installation, and adjustment of the IP to around 9.8kg/cm2 (sorry, my IP gauge is metric...) I was amazed at how much air I could get!

Next step is to build my manometer to quantify my cracking pressure.

[Bryan]

The minute amount you shortened the pin will neither change the flow rate of the 1st stage nor have any effect at all on the cracking effort of the 2nd stage.

If the pin is too short the travel on the pin could be limited...This has no real effect on the surface.....At depth it makes a great deal of difference.

The reason I recommend the pin length that I do is because it WORKS and it works every time. After assembling several hundred Phoenix nozzles and testing them for several years now I try to provide my customers with information that is proven and not experimental. Most divers prefer to know that their equipment will perform no matter where they use it.

Edit: Not saying yours wont work just fine, I'm just trying to give everyone some perspective so they are not under the impression that trimming the pin to a shorter length improves the performance measurably.

[Drado]

I actually agree with the above statement that a pin cut too short would limit the amount of air coming out. The amount that was shortened was just enough to get the mushroom to reach the nozzle face. The total amount of travel of the internals would just be about the same. Thus I agree that this difference will not affect air flow. The reference for cracking pressure was actually just because I want to check cracking pressure, and not for anything else.

From my admittedly limited exposure to the inner workings of a regulator, it is my understanding that in an unpressurized state, the HP seat is held open by the force of the main spring (PN 1000-40).

Actually, when I was asking Luis about pin length, he was more focused on the gap, than the pin length:

"The important thing is the gap.

It is very important that the gap is not so large that the internal parts (the back of the seat) bottoms out before the mushroom pin support."
- L. Heros

The way I understood it was since the seat is held open by the force of the spring, if allowed to "bottom out" then the spring force is mainly on the pin and the internals, and not on the larger surface area of the nozzle-mushroom interface. So maybe its about force and stress on the pin and internals, which is why I figured that his recommendations were more about gap than pin length.

[Bryan]

The Phoenix nozzle started out as a big campfire experiment all the way around. Experimenting with it is part of the joy of owning one. My statement was meant to be cautionary not critical. If 0.021 makes it work better for you then I say go for it.

[Drado]

It is indeed a fantastic bit of engineering.

[Drado]

After having installed my 2nd Phoenix nozzle, I thought I'd just do a quick update on this.

Keeping in mind Luis' admonition to get the mushroom pin holder to reach the face of the nozzle, I measured and slowly cut 'til I got the correct length. The result?



At least now, the pin conforms to the previously published standards of 1.30". Now, as to the discrepancy between my 1st and 2nd, I can't think of an explanation. If I were to hazard a guess, perhaps there were some differences in tolerances within the mushroom holder, or some other factor. Well, I guess I'll have to wait 'til the next rebuild to compare the 2 side-by-side.

[DrunkenParrot]

After having installed my 2nd Phoenix nozzle, I thought I'd just do a quick update on this.

Keeping in mind Luis' admonition to get the mushroom pin holder to reach the face of the nozzle, I measured and slowly cut 'til I got the correct length. The result?



At least now, the pin conforms to the previously published standards of 1.30". Now, as to the discrepancy between my 1st and 2nd, I can't think of an explanation. If I were to hazard a guess, perhaps there were some differences in tolerances within the mushroom holder, or some other factor. Well, I guess I'll have to wait 'til the next rebuild to compare the 2 side-by-side.

Great info Drado, keep us informed on any new info.

[Nemrod]

It is possible that if the gap is significant between the mushroom and the nozzle face that the internals could be jammed/bound up against the sintered filter and cause it to pop out. This especially if the circlip is installed backwards inadvertently. The "sharp" side should be away from force, facing away from the body.

The pin length given by Bryan seems about right, I usually do not measure the pin but trim it one hair at a time until the mushroom bottoms against the nozzle face ever so slightly thus limiting the movement and acting as a stop. Over trimming the pin certainly can affect the flow and would be noticeable at depth if not apparent during initial adjustments that the flow is weak.

I managed to over trim my first Phoenix pin, 006, fortunately Bryan gave me another pin and the second time I was happy with the result.

Nem

[Sharkinabus]

Hi guys,

Just rebuilt my PRAM,

I measured the pin and it was way over-length (had previously been serviced by an LDS in Oz and I'd had issues ever since so I assumed this extra pin length may have been a factor)

I jumped in and trimmed the pin to 1.302" (unfortunately without checking existing mushroom gap ), reassembled and found the mushroom had no gap at all in an unpressurized state!! The volcano orifice is completely home.

My Phoenix is marked 06-123.

Is there any combination of parts that could result in a 1.302" long pin being too short? Wrong HP seat or Volcano orifice perhaps??

When pressurized I get absolutely no LP output..

I guess I need a new pin though can't find one in the VDH store, would someone kindly point me to where to order one?

Cheers,
Paul

[Bryan]

had previously been serviced by an LDS First mistake.

E-mail me if you need a new pin. They are a standard dowel pin trimmed to length. If the body is an 06 then it's a 1st generation Phoenix and the body was slightly longer than the 2nd generation therefore the pin was slightly longer. There is ZERO reason a pin would go bad once it is trimmed and installed properly. This does not take into account the human error factor or a monkey with a hammer repairing scuba equipment.
I will trim the pin for you using one of the 06 bodies I have here for a guide.

[Sharkinabus]

Thanks Bryan!