Scuba Pro G250 and R109 questions

[BigRed96]

Good Dqy All, I have acquired 3 r109 regulators and 1 G250. I have rebuilt 2 of the 109s and the G250. The first 109 breathed easily and cracked around .8. The second 109 and the 250 were hard breathers. I set them up all the same. I adjust the oriface till it just leaks slightly and then turn in the adjustment screw to stop the leak. I learned this off a VDH video. The 109s both have the duropoppet conversion. The easy breathing one has a new diaphragm and what ever the hell the runner thing that holds the shiny s is called. When using the tuning method above the harder breathing 109 and 250 take a lot of adjustment knob to quit leaking. Does the 250 need a new crown? Do the both need new springs? BTW. I am using the same 1st stage to test all three regs.

 

[Couv]

Hi @BigRed96,

I'm going to assume you did an impeccable job of cleaning everything inside the case and airbarrel. Also, there are no lever or poppet issues. That pretty much leaves the seat, orifice, and spring.

If the orifice is bad, it's also likely that the seat will be over-engraved and will require replacement. Check the seat under good light and 10 power magnification if you have it. Run a fingernail over the sealing surface to feel for any imperfections. A dry cotton sway run over the same surface can also find tiny imperfections. You may not actually have to replace the orifice, oftentimes they can be dressed. Search halocline and rsingler's post for the proper method; but to be honest, VDH sells new metal ones and they're worth the price.

Now is a good time to address an issue where other's differ. I maintain that whenever the orifice is adjusted, the purge button should be pressed enough to separate the hard and soft seat. I know that most of the time you can get away with not doing that, but for the little bit of trouble it take to perform that step, it's worth it. This little prophylactic step may save a seat and time.

 

[axxel57]

The new diaphragm probably makes quite the difference.
Just recently I serviced one of my old G250s, coulldn't get the Cracking Effort (CE) not below1,2inch/h2o.
Tried new orifice, same thing.
Then took a new diaphragm, wham, instantly had a CE of 0,8inch/h2o.
I guess that the diaphragms with time loose some flexibility, especially the old, thicker diaphragms.....
But of course the culprit for the higher CE could also be the spring or the orifice........

 

[lexvil]

A quick way to check, do nothing but swap the diaphragm between the hard breathers and the easy breather.

 

[Couv]

I guess that the diaphragms with time loose some flexibility, especially the old, thicker diaphragms....

OK, the flexibility of a diaphragm is a new one on me. I've seen lever marks on the disc of a diaphragm cause erratic lever action. Those striations can be polished out with fine sandpaper. At any rate, the diaphragm can easily be convicted by swapping it out with a known good one. If the problem moves to the regulator where you've installed the suspected part, you've found the problem.

 

[halocline]

Good Dqy All, I have acquired 3 r109 regulators and 1 G250. I have rebuilt 2 of the 109s and the G250. The first 109 breathed easily and cracked around .8. The second 109 and the 250 were hard breathers. I set them up all the same. I adjust the oriface till it just leaks slightly and then turn in the adjustment screw to stop the leak. I learned this off a VDH video. The 109s both have the duropoppet conversion. The easy breathing one has a new diaphragm and what ever the hell the runner thing that holds the shiny s is called. When using the tuning method above the harder breathing 109 and 250 take a lot of adjustment knob to quit leaking. Does the 250 need a new crown? Do the both need new springs? BTW. I am using the same 1st stage to test all three regs.

Are you adjusting the orifice while the reg is pressurized? If so, I would suggest that you stop and only turn the adjusting screw with the purge depressed. If you're already doing that, great.

The duro poppet is the unbalanced poppet, so your 109s are unbalanced with the heavy spring, correct? Do they have original levers, and if so, are the levers on the 2 109s identical. There are several versions of those levers and they all seem to react differently with the newer poppets. I would confirm that the levers are working well with the poppet and that the lever height is appropriate for the diaphragm. I guess the way to do this is to adjust it so there are no leaks without the diaphragm in place, then install it and see if it starts to leak. If so, and you need to tighten the orifice, which drops the lever, then you are adding to the cracking pressure unnecessarily. The fix is usually a new lever. I've experienced this many times with a 109 converting to the s-wing poppet, but never with a G250, although it certainly is possible, especially on an older G250 that originally had the older style fixed-seat poppet.

Have you replaced the lighter spring on the G250? That's a frequent cause for inconsistent tuning.

I've never seen any improvement by replacing a diaphragm, but it's certainly possible. If I were in your shoes, I'd first have a look at the lever height as I mentioned before, once that's worked out try switching springs and diaphragms, even the orifices, eventually you'll isolate the problem.

 

[buddhasummer]

I have all new stock OEM springs, levers, orifices, S-wing poppets, long crown balance chambers etc. if you need, message me. I'm putting together full kits including all those items plus necessary O rings (and flow vane C clip) for 109/156/G250 conversions if anyone's interested. I have enough parts to make about 10 full kits.

 

[axxel57]

OK, the flexibility of a diaphragm is a new one on me. I've seen lever marks on the disc of a diaphragm cause erratic lever action. Those striations can be polished out with fine sandpaper. At any rate, the diaphragm can easily be convicted by swapping it out with a known good one. If the problem moves to the regulator where you've installed the suspected part, you've found the problem.

The lower diaphragm is the new one I put in the G250, which had that quite surprising effect........

 

[halocline]

That upper diaphragm does not look like any SP diaphragm I've seen. I once bought a G250 that had a US divers diaphragm. Needless to say it didn't work so well. Is it possible that the first diaphragm was simply the wrong one, installed by someone else before you got the reg?

 

[buddhasummer]

That first diaphragm looks just like one I had on a Nippon KK Aqualung, it was thick and not very supple at all.