Conshelf 1085 2nd Stage Exhaust Port Size Changes

[James79]

When I get home in a few days I will measure them. It is not the diameter solely of the exhaust valve but the outlet hole in the case and then the restrictive tee that hardly has room for the valve to curl outward. If the case hole in my photo is 26mm I will be really surprised.

I think you are right, I was going off an old message. I'll need to dig mine all out and measure.

 

[Nemrod]

I think you are right, I was going off an old message. I'll need to dig mine all out and measure.

I dunno either, we should quit blathering and start measuring . The intermediate two screw might be close to 26mm but it still has the restrictive tee. The Scubapro 109 is 26mm (top) but it has a well designed tee so while not quite like breathing out through a straw I do notice a restriction when exhaling. The Scubapro CE 156 has the full size 30mm valve (needed to pass CE requirements ?) and in comparison is effortless.

 

[Kupu]

Great information, thanks for the replies.
For 10 years or so I used a SP balanced adjustable with the 26mm exhaust valve, and never had reason to give exhalation effort any thought over the course of many dives in a wide range of dive conditions and depths. So I was curious if the older 1085s had same size valve, and it's interesting to learn the tee design also comes into play on the old 1085.

Not to say I would still feel the same about a second stage with 26mm valve today, nowadays I nerd out on regulators with exceptionally low WOB.

 

[Nemrod]

Keep in mind all that math stuff. It would seem at casual thought that what is the big deal going from say 24mm to 26mm or then to 30mm. It is just a couple of mm? But as the radius increases, the area increases by the square of the increasing factor. That little bit is actually a huge increase in area. Well, there is more to it because the periphery of the exhaust valve (and lift and flexibility) and how it interplays with the exhaust manifold/tee is also huge.

 

[Geo7]

Can anyone lay out which years the exhaust ports on the USD 1085 second changes made the switch to the large exhaust ports, and slip on exhaust tee? Its my understanding that exhaust port size and screw on/ slip on tees were about the only changes to that 2ns stage over its life. I'm in the market and would like to know which years/models to look for.

Great question, I love threads like these...

 

[Nemrod]

So I went through my VDH downloads and this photo I already posted is from the 1973 catalog. So, then, that is the for sure demarcation between good and bad. However, the 1972 catalog does mention the "new low effort exhaust" so considering as well the catalogs were not always absolutely reflective of product for an entire year, I am going to now say 1972.



The 1969 was the last of the two vent covers, afterwards the smooth front covers with the peripheral vents ruled the day. But the two screw tee went away with 1971. I think the 1971 1085 had the odd intermediate exhaust valve still with the two-screw tee. I think it was 1973 or 1974 that USD AL issued the warning to dive stores concerning the high exhaust effort of earlier models.

James

 

[PartFish]

.....Lastly, as you said you're in the market for one, I have a few that I could part with. Let me know what you're after for certain and I can probably have you sorted.

James,

Much appreciated! I have a few locally im trying to obtain right now, but if they dont work out, ill certainly reach out to you. Over the next few months I'd like to round up the parts and put together a set for ice diving. Im looking to the slip on tee, large port 2nds and sealed DIN first. I'd love a conshelf/titan 1st stage, but they're hard to come by, so the Dive Rite FT1 is what I'm looking at right now.

 

[James79]

James,

Much appreciated! I have a few locally im trying to obtain right now, but if they dont work out, ill certainly reach out to you. Over the next few months I'd like to round up the parts and put together a set for ice diving. Im looking to the slip on tee, large port 2nds and sealed DIN first. I'd love a conshelf/titan 1st stage, but they're hard to come by, so the Dive Rite FT1 is what I'm looking at right now.

DIN is the hard part for Conshelf 1sts... You don't see a whole lot of them. Sealed isn't hard (Conshelf supreme or dry sealed Titan are fairly common).

 

[PartFish]

DIN is the hard part for Conshelf 1sts... You don't see a whole lot of them. Sealed isn't hard (Conshelf supreme or dry sealed Titan are fairly common).

Yes, im seeing yoke conshelf and Titan 1sts everywhere!

 

[James79]

Here you go: Modern DIN Aqualung US Divers CONSHELF 14 scuba diving dive XIV regulator | eBay
More than I'd normally pay, but I also don't DIN... Swap a supreme or dry sealed end cap on, and good to go.