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Post by vance on Oct 11, 2020 13:36:47 GMT -8
I finally got around to making the GL style cover that I've been claiming I would for months (maybe years?). It is pretty much James' 3D SJ, but I milled a channel into the top of the valve for airflow into the tube. It's a 1/4" stainless tube silversoldered to the stainless cover. The opening of the tube hangs over the valve body directly over the channel. I don't think the unmodified valve body allows enough air to pass. I think tapping into the bevel is necessary to make the cover concept work well. It is a permanent modification, but doesn't prevent the valve from working in the stock configuration. I think it works a bit better than the 3D SJ, but there's the modification downside. It still isn't a GL....
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Post by vance on Dec 27, 2020 16:23:32 GMT -8
So I've determined that the best I can do is try to make as little change to the valve as possible. I experimented today with an extra valve body, and improved the SnorkelJet equipped Scuba's air delivery some. I milled a trench in the face of the valve body, much like the hole drilled in the side of the S-D mod. The trench leads directly into the nozzle of the SJ. I started with a 2.5mm wide by 1.5mm deep. There was some improvement, but it didn't cause the venturi-like blast I expected. I widened the cut to 3.5mm. That improved things even more, but still no joy. I'm looking for runaway freeflow! There is a considerable amount of leakage around the SJ, and this particular version of the SJ isn't pointing the nozzle directly down the intake horn. I have a different version that has a longer nozzle that enters the intake horn rather than just points at it. I'll try that one next. BTW, I discovered that the long valve body (and yoke nut) is made of steel, not brass like the short version. That's probably why HW only made a few long ones. When they changed to brass they shortened it, but also changed the thread pitch to keep parts from being swapped. Here I go quoting myself again. But, there's updates to this experiment. Being bored today, I took my absolutely awesome performing Super Deluxe valve and machined the bajayzuz out of it. I used a ball end cutter in the mill to make a 1/4" tubing sized, slanted groove in the same channel as the original drilling. The idea is to make a cap with a soldered venturi tube that fits into that groove. The slant is necessary to point the tube upward so it points down the intake horn. I made the stainless cover, and soldered a tube to it. The tube is threaded at the far end for a removeable jet. The idea is to allow for tuning via different sized jet openings. Making this is not as easy as it sounds. To get everything aligned, I first cut a rough blank, then soldered the tube to it. I ground and filed the cap circumference to fit the valve. Then, I fitted the cap to the valve by filing everything away that kept it from seating well. I marked and drilled the mounting holes and the HP pin hole.All of this is in aid of reinventing the GL valve. The design of the GL valve is a deceptively simple thing of beauty, which took some doing to accomplish.
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Post by vance on Dec 31, 2020 12:36:52 GMT -8
Here's the jet: it's just a stainless phillips screw with a hole drilled through.
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Post by vance on Dec 31, 2020 15:27:52 GMT -8
The performance of the valve with the open tube is good. It seems to provide a good amount of air, but it doesn't seem to be as good as a GL.
This could be a perceptual problem, due to the sound. It isn't as loud.
It appears that drilling calibration holes isn't necessary as the cover stands. The jetted venturi does not cause freeflow. It might be that there's too much leakage around the cap.
Hmmm.
On the bench, the jet does not seem to improve or decrease performance of the venturi over the open tube: restricting the opening in the tube creates even more leakage?
So, the thing to try now is sealing the cap with RTV, in hopes that it will significantly increase the outflow from the tube.
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Post by vance on Dec 31, 2020 15:52:44 GMT -8
So, the concept has changed. The experiment, which started with the SnorkelJet air director, was based on making no, or minimal modifications to the regulator. Mods were mostly about filing out the locating flat on the top can to allow repositioning of the valve. The original SnorkelJet, and the plastic Ghost SnorkelJet work pretty well.
The 3D SnorkelJet is the ultimate part so far, since it requires no mods. It improves the performance of the Scuba, but isn't as effective as the original and Ghost, IMO.
Then, trying to limit mods to the reg and valve body to nothing drastic, the next attempt was to make a different screw-on cover/venturi tube setup. This included cutting a shallow trench across the valve face to permit better airflow into the tube (see the top two posts on this page). It works a bit better than a 3D SnorkelJet.
The best performing mod so far has been an angled drilling into the edge of the valve that enters the HP pin bore. The valve was capped with a stainless cover, and an air director was added to extend the intake horn. This was the Super Deluxe. It worked very well. It was much like a GL.
Not satisfied with success, I then did what you see above to it.
It's how I roll.....
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Post by nikeajax on Dec 31, 2020 16:46:38 GMT -8
PY, if I'm not mistaken that chamber is called a plenum Have you RTV'ed the cover on to see if hat helps? JB
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Post by vance on Dec 31, 2020 18:52:24 GMT -8
I will probably do that tomorrow. I expect it to funnel the air flow right down the pipe. Photos to follow.
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Post by nikeajax on Dec 31, 2020 19:59:34 GMT -8
FYI: the idea behind the plenum is, it's a reservoir that boosts what you're doing. I know you're familiar with cars from the 1950's: way back when they used a vacuum reservoir to boost the power reserve on power brakes to give them more, well, a lot more -ooomph! So, that said, I'm wondering if the bleed-out is negating what should be gained for you? Just thinking out loud is all JB
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Post by vance on Jan 1, 2021 16:54:37 GMT -8
Yes, there's considerable leakage from the cover. Other experiments like this one, chronicled elsewhere, showed that gluing the cover on with RTV is very effective at sealing the leaks, leaving only the amount that can get around the HP pin.
I have just RTV'ed this cover to the valve. Tomorrow will tell. I'm hoping for runaway freeflow.
The issue here will be, if RTV does seal it up and I get the result I want, is the RTV seal dependable over time?
I had another idea about filling the top of the valve body with JBWeld, and replicating the GL machining. That will take some thinking and planning.
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Post by vance on Jan 2, 2021 11:11:49 GMT -8
Well, it works pretty well, but still no GL-like gush. Or even Super Deluxe-like.
I think I've reached the pinnacle of performance with the airstream coming out of the top of the valve, and using a collector/director.
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Post by vance on Jan 2, 2021 14:16:12 GMT -8
I took it apart and made a delrin plug/form for the HP pin bore and filled the trench and valve top bevel with JBWeld. I'll machine the top flat and drill the side like the SuperDeluxe, only this time the hole will enter the HP pin bore exactly like the GL body. On the S-D, the drilling entered the pin hole a little too high so it didn't intersect well with the pin cut-away. I think this is why air directors/S-Js don't work like the GL, no matter what you do. There isn't enough airflow past the pin. The GL gets the air stream from the middle of the pin bore and the cut-away allows more air to pass the pin than the flat sides of the pin do. I'll either patch the top with JBWeld or just cap it with a stainless cover. I might try the tube again, but IDK. More photos to follow.
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Post by vance on Jan 2, 2021 17:26:36 GMT -8
You might be wondering why I cut this valve body twice and then filled it back in with JBWeld. The reason is that I don't want to cut up any more valve bodies. The results I got from the first two experiments were mixed, so I want to keep forging ahead.
But, I only have 2 orphan valves, both of which I have modded, and I don't want to cut any more. If, by experimenting on this one, I find the answer that I'm looking for, I might move on to modding other valves. Until then, I'll limit my mutilating to this one as long as I can.
In case you all have forgotten or if you have joined the party late, here's the reason for the obsession about modding an HW Scuba valve to a GL type venturi valve: I want to make a balanced single stage regulator with a venturi that's as good as a GL.
This requires modding a long Scuba valve by installing Conshelf guts, like the Misuba Rev4, AND figuring out the venturi or venturi-like performance. I have already accomplished the balanced mod on the Misuba Rev4, and achieved the GL performance with the Super Deluxe. But the S-D has a short valve, which can't accept the Conshelf balanced guts.
I am very reluctant to mod a long valve due to their rarity. I am experimenting on the orphan short valve to perfect the GL type air supply, so I might feel comfortable enough to do a long valve in case of success.
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Post by vance on Jan 2, 2021 17:28:06 GMT -8
I liked myself again!! Meant to edit....
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Post by scubalawyer on Jan 2, 2021 17:51:29 GMT -8
My mom said that would make you go blind!
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Post by vance on Jan 2, 2021 18:33:25 GMT -8
Not quite yet. It's happened 2 times so far. I need to get slightly more magnification for my readers, though....
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