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J valve

Discussion in 'Vintage Equipment Diving' started by gordanm, Jul 12, 2019.

  1. gordanm

    gordanm Garibaldi

    # of Dives: I just don't log dives
    Location: Europe
    2
    0
    1
    Hello,

    looking for a working/good condition vintage J valve M25x2, not US DOT 3/4 I want to use my old regulator, which is 40 years old, but it cannot fit my current valve (DIN with INT adapter). The valve neck is wider than the internal part of the yoke, so I cannot attach it.


    Any suggestion where to find it, appreciate that very much.


    Thanks.
     
  2. Akimbo

    Akimbo Lift to Freedom Volunteer Staff Member ScubaBoard Supporter

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    Does such a thing exist? I thought the M25 cylinder standard came well after J valves lost favor in the market. Were J-valves ever popular in Europe? I was under the impression that they were only used in North America.
     
  3. W W Meixner

    W W Meixner Rebreather Pilot

    # of Dives: 500 - 999
    Location: Ontario Canada
    521
    337
    63
    Gordan...

    I have a rebuilt DA Aqua-Master...which had a small yoke fitting like you're describing...I had a couple of spare modern Mares yokes...with the littlest amount of ''Dremel'' massaging retro-fitted perfectlly to the DA....I retained the original yoke which can be re-fitted anytime...

    Consider replacing the yoke as opposed to trying to find an old valve...

    Another option is to replace your combo valve with a standard modern yoke valve...which has a considerably smaller head...

    Best...

    Warren
     
    Ghetto Diver and gordanm like this.
  4. gordanm

    gordanm Garibaldi

    # of Dives: I just don't log dives
    Location: Europe
    2
    0
    1
    Warren, many thanks, good advice !
     
  5. 2airishuman

    2airishuman Solo Diver

    # of Dives: 100 - 199
    Location: Greater Minnesota
    2,324
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    I had an M25 cylinder with a 1962 original hydro date. It had a Sportsways K valve, but there were certainly J valves around back then. I ended up selling it.
     
  6. W W Meixner

    W W Meixner Rebreather Pilot

    # of Dives: 500 - 999
    Location: Ontario Canada
    521
    337
    63
    My pleasure...

    Be careful/mindful of the allowable working pressure of the original yoke...most of which were designed to be used on old LP cylinders...2250 PSI...or there-abouts...they should be stamped...

    Using these old yoke assemblies on a 3442 HP steel cylinder could be a problem...

    Stay Safe...best...

    Warren
     
    Ghetto Diver and JackD342 like this.
  7. Akimbo

    Akimbo Lift to Freedom Volunteer Staff Member ScubaBoard Supporter

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    Are you sure it was a metric M25? The 1962 Sportsways describes it as: 3/4" "0" ring straight thread connection,
    the only system that meets military specifications (MIL P-5514)

    upload_2019-7-12_14-33-46.png

    As I recall, the Sportsways straight thread O-ring seal was based on the SAE straight thread boss while the 3/4" straight thread standard introduced by US Divers in 1960 was based on NPTS (straight thread pipe) and adapted to use with an O-ring. Even though both say 3/4" one is based on the actual thread diameter while the other is based on a pipe size, which is roughly based on the inside diameter plus the thickness of a heavier wall pipe. The US Divers design was accepted by the rest of the diving industry in the US while the Sportways version remained proprietary and was ultimately abandoned.

    More valve O-ring history: Scuba Cylinder Valve Installation
     
  8. 2airishuman

    2airishuman Solo Diver

    # of Dives: 100 - 199
    Location: Greater Minnesota
    2,324
    1,502
    113
    It was certainly metric, but upon reflection and checking my notes, I believe it was an M18.
     
  9. AfterDark

    AfterDark Solo Diver

    # of Dives: 2,500 - 4,999
    Location: Rhode Island, USA
    7,649
    3,151
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    Make sure the DIN adaptor is threaded in all the way, measure it to be sure. I know someone who had the same problem and I was able to track it down to the adaptor not seated full. I cleaned the threads and lubed them with a small amount of silcone. Any reg I had including a Aqua Lung Jet Air double hose fit after that. I've a DIN adapter on my pony with 1960's USD Calyspo J on it, fits fine.
     
  10. Bob DBF

    Bob DBF Solo Diver

    # of Dives: I just don't log dives
    Location: NorCal
    5,899
    5,490
    113
    My experience was the yoke flexed from the pressure and blew the o-ring. I was a bit surprised, and once I figured out what was going on, I now pay more attention to where I attach my vintage regs. I have not had the issue with the 3000# yokes, and the new yokes are good to go.

    The new valves tend to have a larger head, even the ones that are not convertable, which will stop the use of some older yokes, and unfortunate since I have a Sherwood from '80 something made for 4000# service, but the yoke is too small for most, if not all modern valves.


    know your limitations

    Bob
     

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