Are Converted Scubapro 109's a weak link?

[buddhasummer]

Shot it over this morning

I'll send over files tomorrow.

 

[lexvil]

It depends on the dive shop.
My dive shop will work on any of that stuff.
There is a tech there that is a 109 aficionado and has done 156 conversions, restorations, etc.
Any G250, no problem, they have spare parts laying around and will gladly do whatever they can to get old stuff up and running if possible. Most of the time it is possible. Their philosophy is “Yes we can” not “No we can’t, buy something new or get out of here”, because with the latter attitude you run the risk if pissing someone off with your tone and they could go somewhere else to buy the new reg, and you’ll never see them again.
I even turned them on to some of our DIY sources for parts which they didn’t know about because they are not really into the internet world. Even though they are primarily a Scubapro shop, they are not a puppet for corporate Scubapro and believe in taking liberties to help accommodating customers in a “custom” fashion.
They continually ask me if I’d like to take the tech position some day because the current tech want’s to retire and I’m romancing the idea. I would continue the tradition of accommodating customers any way I could the same as they do now.

Best way to ruin a hobby.

 

[OrcasC205]

Can you imagine the amount of lawyers that would come out of the woodwork if someone had an accident on a 'converted' 109?
Same reason why they didn't want to work on the mk25 with mk10 yoke. Are they the same? probobly. Does scubapro say they're compatible? No.

It's hard to argue that point when Scubapro's own schematic shows both the 109 and the Balanced Adjustable (156) with the only difference being the poppet part numbers.

 

[Nemrod]

@Nemrod you cannot fit a G260 barrel into a G250.

That is not what I said, yes, the barrel will not fit in part due to the clocking puts the outlet and Venturi differently.

 

[Eric Sedletzky]

Best way to ruin a hobby.

Yeah, maybe you’re right, but it would only be one day a week.
The ulterior motive is obtaining parts for my personal stuff.

 

[Angelo Farina]

Your tech or whatever is full of dung!

There are two issues with balanced conversions of the 109. One is the relatively small exhaust valve and slightly restrictive tee compared to the G250/G260. The other is lack of a Venturi control. But all in all a 109 will perform very close to the newest regulators.

It is true that the old 109 has a smaller exhaust valve than the G250. The latest version (156 with CE mark), indeed, has the larger valve and is universally recognised as the best full-metal 2nd stage ever built.
I have 6 109, 1 129 (left handed 109) and 1 156.
I love my 109s.
A bit of exhalation resistance is not a problem if you breath properly (slow complete exhalation, inhalation up to 75% of vital capacity, followed by a 5 s inspiratory pause).
It can even be an advantage, as it keeps the average pressure along the whole respiratory cycle to be slightly positive, which is a good thing for preventing pulmonary edema.
A restricted exhaust can only be a problem if the diver goes in hypercapnia and looses control on his breathing, switching to short and fast hyperventilation.
But, again, the proper long breathing which is automatically triggered by the 109 is a good measure for preventing this issue.
In conclusion, whilst a G250V or a G260 are my suggestion for people buying their first reg, I see no reason for people already owning a 109 to switch.

 

[Nemrod]

It is true that the old 109 has a smaller exhaust valve than the G250. The latest version (156 with CE mark), indeed, has the larger valve and is universally recognised as the best full-metal 2nd stage ever built.
I
A bit of exhalation resistance is not a problem if you breath properly (slow complete exhalation, inhalation up to 75% of vital capacity, followed by a 5 s inspiratory pause).
It can even be an advantage, as it keeps the average pressure along the whole respiratory cycle to be slightly positive, which is a good thing for preventing pulmonary edema.

No, the CE 156 BA would be recognized as the best all metal second stage save possibly for the current A700. The 109, meh, they are pretty but the WOB exceeds that of the 156 and the G250 due to the exhaust effort. You can rationalize this all you wish, more is still more effort. Further, the soft purge cover is prone to free flow in current or scootering and there is no Venturi switch to control that.

I have been diving continuously since 1966 and I seriously doubt but a very few people have better breathing characteristics/control than me. And I was a semi-professional triathlete and I have been a serious cyclist and amateur athlete my entire life. I breath correctly. You may not, but I do, and I do not need any lessons in that regard.

 

[Angelo Farina]

No, the CE 156 BA would be recognized as the best all metal second stage save possibly for the current A700. The 109, meh, they are pretty but the WOB exceeds that of the 156 and the G250 due to the exhaust effort. You can rationalize this all you wish, more is still more effort. Further, the soft purge cover is prone to free flow in current or scootering and there is no Venturi switch to control that.

I have been diving continuously since 1966 and I seriously doubt but a very few people have better breathing characteristics/control than me. And I was a semi-professional triathlete and I have been a serious cyclist and amateur athlete my entire life. I breath correctly. You may not, but I do, and I do not need any lessons in that regard.

The WOB measurement machine weights equally inspiration work and expiration work.
But due to human anatomy, that equal weighting is wrong.
Our respiratory apparatus is more strong and powerful while exhaling.
Such slight exhalation resistence has an healthy effect, pushing away blood from your lungs and making your alveoli to extend, working better.
I am an engineer, so I was trained to thrust masurements results over human sensations.
But after 40 years of experiments measuring quantities related to human perception I learned how misleading some "objective" measurements can be.
The respiratory cycle of a 109 is more natural, pleasant and healthy than the respiratory cycle of the 156 CE.
And the G250V-G260 are even "better" on measurement of WOB, thanks to the stronger venturi effect, but not really better in practice.
In any case these differences are small at normal depths.
Only people diving deep in air (below 50 m) will perceive the additional exhaust resistence of the 109.

 

[buddhasummer]

That is not what I said, yes, the barrel will not fit in part due to the clocking puts the outlet and Venturi differently.

Sorry, misread post, assuming I now understand yes, orifice, poppet, spring and balance chamber will all work in a G250, the G260 exhaust valve all fits a G250. Lever can be used but I'd not recommend it as it ends putting a lot of pressure on the seat causing deep indentation in a short space of time.

 

[rsingler]

Can you imagine the amount of lawyers that would come out of the woodwork if someone had an accident on a 'converted' 109?

Imaginary horribles. What a load of nonsense!

So tell me why in my official Scubapro "expert" Level III class, René Dupré distributed "Jewels from Jules" showing all the old schematics, complete with which parts were "No longer available", if they were not meant to be serviced?
And, Hello! A service bulletin specifically describes the upgrade from old poppets to new. And, Hello! Scubapro has not printed new full schematics since 2014. They just dribble out individual stuff. And their new manuals? Horrible translations from the Italian with no graphics and odd part names. Scubapro's official support to the technician remains marginal, though calling in still works great, and René Dupré remains a mainstay of training and advice.

But sure! Cry "Unauthorized"!!! I'm sure that will sell another newer (but not significantly better) regulator. My shop will service them all.
Unless you're a SB regular, you'll never be able to tell the difference between a G250, an A700 or a C370. Cracking effort? What's that?

Stop frightening people.