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Got my Trieste to breath better (info for geeky DIY reg repairers only) :)

Discussion in 'Vintage Equipment Diving' started by Scuba Lawyer, Sep 2, 2020.

  1. Scuba Lawyer

    Scuba Lawyer Manta Ray

    # of Dives: 5,000 - ∞
    Location: Laguna Beach, California
    708
    2,004
    93
    Well, it took a year’s worth of ‘spiramentin and the knowledge of those far more technically savvy then me, but I finally got my Trieste to breathe well.

    Most folks will tell you, me included, that a stock Trieste most often breathes like you are sitting at the bottom of the pool sucking air through a garden hose. (I have heard of exceptions but not many). It took a longer-than-normal custom made lever from Phil Y., and a 2nd Stage body drilled and equipped with adjustable venturi set screws courtesy of Bill T. of Texas, to make my Trieste extremely easy breathing.

    I’ve gotten my stock Trieste down to 1.5" H2O cracking pressure (at 150 psi IP) but the venturi effect is non-existent and sustained cracking is 3+ inches of H2O. With Phil’s longer lever I got cracking pressure down to .7" H2O but the sustained cracking pressure didn’t change. Enter Bill T. with the concept of drilling two holes in the 2nd Stage body and putting tiny set screws that will move up and down to adjust the venturi.

    Today I installed Phil’s lever and Bill’s modified 2nd and cracking pressure is still .7" (now at 130 IP) but the venturi now kicks in (after about 4 or 5 one-half turns of the set screw outward from the closed position) immediately with a sustained effortless flow. I checked the venturi on each ½ turn of the set screw outward. At first the venturi was too powerful and it sucked the diaphragm down and held it there in freeflow mode. I finally found the sweet-spot and the reg now breathes fantastic. Very powerful venturi actually. Put a dab of locktite in each hole. Can’t wait to try it out in the ocean!

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  2. Sam Miller III

    Sam Miller III Scuba Legend Scuba Legend

    # of Dives: 5,000 - ∞
    Location: CALIFORNIA: Where recreational diving began!
    5,065
    3,887
    113
    @Scuba Lawyer
    I will not only give you a "like" but also a FANTASTIC !
    Continue to preserve the very short history of dive regulators and certainly continue posting pictures

    Sam Miller, 111
     
    John C. Ratliff and Scuba Lawyer like this.
  3. Scuba Lawyer

    Scuba Lawyer Manta Ray

    # of Dives: 5,000 - ∞
    Location: Laguna Beach, California
    708
    2,004
    93
    Completed my Modified Trieste rebuild. Sounds like a sports car engine when the venturi kicks in. :)

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