Scubapro Pilot

[Golan68]

Yes , the material against the edge must be soft. I noticed that Scubapro marked them as neupren, I used silicone. I belive that price of the oring is a factor . what do you think will be the best and should it be hard or soft?? silicone, epdm, viton , nitril???!

 

[redacted]

I suspect modern materials like EPDM were not readily available when the pilot was introduced. I would opt for a more modern material with good scuba characteristic with special attention to resisting the taking of a set and in a lower hardness like duro 60 or 50. I would be looking for EPDM.

Acording to Parker Seals, both silicone and EPDM (and viton) have top ratings for set resistance. Neoprene is only rated as fair. EPDM ratings in all scuba related categories (not including things like fire and oil) is as good or better than neoprene, silicone, and nitrile.

 

[JerryPi]

I was having trouble disassembling my latest addition , the Pilot, without a readable schematics.
Parts were really stuck together and I didn't know what to unscrew and what to pull, while being gentle not to break anything.
Here are my results:


Now does anyone have that schematic in decent enough resolution to read?
Any recommendations on how to remove the dive/pre-dive sticker without damaging it are also more than welcome!

 

[Couv]

I'm guessing you want to remove the "Pre Dive" sticker because you expect hardware under it exist that must be removed. If the switch is like the one on an AIR 1 removing that decal will be a disappointing experience for you. (Don't ask how I know) As it turns out, the switch has spring pawls designed into it, so take a thin wedge shaped object (think of a plastic chisel) and gently push it under the switch and it will pop free. To re-install it just push it back into place.

Again, this is based on my experience with an AIR 1-one of the Pilot masters should verify this before you proceed.

 

[redacted]

I'm guessing you want to remove the "Pre Dive" sticker because you expect hardware under it exist that must be removed. If the switch is like the one on an AIR 1 removing that decal will be a disappointing experience for you. (Don't ask how I know) As it turns out, the switch has spring pawls designed into it, so take a thin wedge shaped object (think of a plastic chisel) and gently push it under the switch and it will pop free. To re-install it just push it back into place.

Again, this is based on my experience with an AIR 1-one of the Pilot masters should verify this before you proceed.

According to the schematic and my memory (we can probably trust the schematic), it is screwed on and must be removed to replace the o-ring. So what we really need is a replacement adhesive. (Or I might consider scratching an arrow into the chrome if I thought I could remember what it meant. )

 

[JerryPi]

When I received my AIR1 it was already missing it's sticker. However I never understood why you would need to remove the AIR1's sticker in the first place. I never could repress the spring prawls on mine, so I always remove the switch in a manner you describe (I use a plastic flat head screwdriver and then slowly twist it).

The Pilot's switch is of a different design. Behind the sticker are two Phillips screws that hold the friction pad and back-plate on the inside. So the only way to remove the switch (to clean the sand behind it and to replace the o-ring) is to remove the sticker. But it turns out the sticker is well made. I managed to peel it off without any damage. I used a hairdryer to heat it up and then used a pick in the corner to gently lift it. Then I worked my way under it and it came off real easy. It seems to be made of thicker material (somewhat like the adjustment knob stickers of today).

Was the AIR1 sticker just an ordinary thin sticker?

 

[Couv]

Thanks guys for clarifying that.

Yes, JerryPi the AIR 1 PRE-DIVE decal was fixed to a thin piece of material-plastic if I remember correctly. If I still had that regulator a small piece of aviation speed tape (very thick aluminium tape with a strong adhesive) would have mind melded with that switch.

 

[JerryPi]

My Pilot had now been cleaned and had it's o-rings replaced.

Because I don't stock neoprene or silicone o-rings I used EPDM and NBR. I immediately had a problem with fitting the stop over the poppet o-ring. There is just no way I can fit the stop over a 2-011 duro 70. The stop need the o-ring deformed so it slips in it, perhaps duro 50 would do it but I don't have one at the moment. The best I could do is a 2-010, but it made the sealing area smaller which can cause a leak on some exhales if it doesn't hit the edge just right. Are neoprene o-rings more deformable than EPDM or NBR or will any lower duro (50?) do the job?

After making the initial adjustment to stop the flow by screwing in the cap, I tried adjusting the lever play and diaphragm connecting rod length. Basically no mater what I did, with the regulator in dive position, i didn't get the usually described chatter, it was more like rapid gun fire bursts that almost knocked my teeth out. Only if i allowed the lever to have substantial free play it was a little better, but then every time you breath it would go bang when the lever engages. The inhalation effort was about 0.2inH2O in dive and 4inH2O in pre-dive, both numbers are way off. After a few hours of tinkering and trying different things I went back and thought about that silicone o-ring. Silicone o-rings are not best suited for dynamic applications due to low abrasion resistance and higher friction, so why would one explicitly use a silicone o-ring on a moving poppet? Then it hit me.

When the pilot valve opens, the gust of air rapidly lift's the poppet and fills your mouth with too much air, which then raises the pressure in the regulator body pushing out the diaphragm, effectively closing the pilot valve. So a little friction here to slow the poppet down would definitely help in stabilizing the valve. So I changed it back to the sorry looking original silicone o-ring and the situation improved greatly. It still chatters, but at least full auto fire is gone . I'll try with a new silicone o-ring and see if it makes a difference.

I also suspect I have a bent lever or a deformed diaphragm or possibly both, because when I exhale the air pushes the diaphragm out too much causing the lever to overextend that way and engage the valve again. This then opens the valve and the venturi sucks the diaphragm back in closing and yet again opening the valve. Adjusting the aspirator is also a major factor in these oscillations. At least in my case, any other position than aligning the opening with the mouthpiece causes air to blow down in to the body, pushing out the diaphragm.

I hadn't had so much fun in ages!

 

[Golan68]

just returned from Eilat after diving with the Pilot. it performed flawlessly i was very impressed. about a year back I had from time to time what you described, this chatter. but now it's completely gone, and the regulator was the same from surface to 35m.
so, looking at what you wrote I wanted to give you some ideas. the first one, when the lever is loose the servo valve must be all the way down. if the o-ring at the bottom is wrong then it will make trouble since, the valve will let air prematurely.
second, i used all o-rings , either epdms or silicons. third , use christo lube [white, i think it's 129] the lube makes big difference.
forth, if it flows air when you exhale, then adjust from the membrane connector screw and not from the lever.
last use your senses and common sense.
the only weak point i found with the pilot is that it was heavy since i'm used to the D400. and btw, even next to the pilot the D400 is a great performer, so I didn't find any sense using my G500 or the BA though i had them with me as well ...

---------- Post added August 31st, 2014 at 10:31 PM ----------

haa, and looking at the nice picture you posted, i think the your lever is just fine. the bent part should face forward if my memory doesn't deceive me...

 

[John C. Ratliff]

I am going to resurrect this thread, as I this week purchased a Mark VIi/pilot/109 and a second Mark VII/109 from Craig's List at a very, very reasonable price. I have wanted a Pilot for quite some time, as I have used my Mark V/A.I.R. 1 since I bought it new in the early 1980s.

The Pilot leaked badly when I first got it (allowing me it reduce the price). I sq irked silicone spray into it, let it sit for a while, then pressurized it, and it did not leak this time.

I plan to disassemble it, thoroughly clean it, and probably replace O-rings to get it going again. This thread will help a. Lot.

SeaRat