Questions About ScubaPro 109 2nd

[Litefoot]

I bought a beautifully restored MK10 and 109 from @Wiznutaggie that were part of Couv’s collection earlier this year. I’d like to find another 109 to build a complete backup reg set. I just adore the classic look of the all-metal 109.
Have you found any reliable eBay sellers? If it does not have the s-wing poppet upgrade, is that something I could handle if I had a kit? Of course, if anyone here has one available, I’m all ears.

 

[Kupu]

I have plenty of 109s and parts, not yet restored but maybe of interest. Message sent.

 

[mr_v]

You should be able to perform a poppet upgrade w/o major issues. Do you have Harlow's Reg Maintenance or Reg Savvy by Wolfinger?

I haven't done 109s but have purchased and restored a few G250s. Best specimen are pawnshop finds that saw little use. Most of the time I will do a full upgrade by replacing the following:

- Poppet
- Spring
- Orifice (if it is not brass or "gold")
- Diaphragm (rarely)
- All o-rings

These regs are old, so even the most pristine original examples may have weakened springs and shot o-rings. A typical $100 "find" ends up being close to $200 when fully restored and equipped with new hoses. That does not account for the time and the extra tools.

Note, if you'll have to tune the reg, so that's where additional knowledge/tools may be handy.

 

[rhwestfall]

One of the biggest challenges with changing a 109 to a 156 with the modern s-wing is an issue with the lever. There is really the need for a few of the different models of them (think there are 3 or 4 versions of levers) to find the one that works on your reg (sometimes the spring too - there are two versions of them also). It may be best to buy an already updated one from someone who knows what they are doing and has the parts to be doing the "swap until it works" method. It can be quite the rabbit hole to go down. Been there, done that. I have a number of 109/156 seconds in my collection...

The other consideration is to keep it as a 109. They are great regs even if kept as unbalanced. If you are diving a balanced first stage, there really isn't too much of a need to go balanced on the second. The seats for the 109 become the only real maintenance need, and can be sourced or made really cheaply (there is info here in SB about how they can be punched from sheet material)....

 

[Litefoot]

You should be able to perform a poppet upgrade w/o major issues. Do you have Harlow's Reg Maintenance or Reg Savvy by Wolfinger?

I haven't done 109s but have purchased and restored a few G250s. Best specimen are pawnshop finds that saw little use. Most of the time I will do a full upgrade by replacing the following:

- Poppet
- Spring
- Orifice (if it is not brass or "gold")
- Diaphragm (rarely)
- All o-rings

These regs are old, so even the most pristine original examples may have weakened springs and shot o-rings. A typical $100 "find" ends up being close to $200 when fully restored and equipped with new hoses. That does not account for the time and the extra tools.

Note, if you'll have to tune the reg, so that's where additional knowledge/tools may be handy.

I got Wolfinger’s book a couple of months ago and started studying the sealed diaphragm sections, but now that I have the 109’s, I’m reading the unsealed piston section with great interest. Good book.

One of the biggest challenges with changing a 109 to a 156 with the modern s-wing is an issue with the lever. There is really the need for a few of the different models of them (think there are 3 or 4 versions of levers) to find the one that works on your reg (sometimes the spring too - there are two versions of them also). It may be best to buy an already updated one from someone who knows what they are doing and has the parts to be doing the "swap until it works" method. It can be quite the rabbit hole to go down. Been there, done that. I have a number of 109/156 seconds in my collection...

The other consideration is to keep it as a 109. They are great regs even if kept as unbalanced. If you are diving a balanced first stage, there really isn't too much of a need to go balanced on the second. The seats for the 109 become the only real maintenance need, and can be sourced or made really cheaply (there is info here in SB about how they can be punched from sheet material)....

Thanks for that! @Kupu is setting me up with an upgraded 109 to match my existing one. Just an absolute gem of a person to work with. Maybe I’ll think about getting some older units to diddle on after I learn a little more.

 

[Eric Sedletzky]

A current G200 kit will work if you want to leave it as a 109.

 

[Nemrod]

And just to say, the plastic orifice works fine. Not as sensitive but more stable if that might make any sense. My wife's new 109, at least she claimed it. It does match her white Go-Sport fins and mask.



I would go ahead with the balanced conversion. The WOB is higher than a G250 due to the less effective Venturi and smaller exhaust valve, but still fine for diving, especially for smaller people with less inspiration tidal volume.

 

[OrcasC205]

And just to say, the plastic orifice works fine. Not as sensitive but more stable if that might make any sense. My wife's new 109, at least she claimed it. It does match her white Go-Sport fins and mask.



I would go ahead with the balanced conversion. The WOB is higher than a G250 due to the less effective Venturi and smaller exhaust valve, but still fine for diving, especially for smaller people with less inspiration tidal volume.

Just out of curiosity, where did you source the white diaphragm cover? Or did you mold it yourself?

 

[Nemrod]

Just out of curiosity, where did you source the white diaphragm cover? Or did you mold it yourself?

The Scuba Museum has them hidden away on one of the products pages. They are pretty nice reproductions. Very soft and flexible. I wish there was also orange and Scubapro blue. Maybe someday .

 

[buddhasummer]

And just to say, the plastic orifice works fine. Not as sensitive but more stable if that might make any sense. My wife's new 109, at least she claimed it. It does match her white Go-Sport fins and mask.



I would go ahead with the balanced conversion. The WOB is higher than a G250 due to the less effective Venturi and smaller exhaust valve, but still fine for diving, especially for smaller people with less inspiration tidal volume.

I'm all about plastic orifices now, mostly because they are less than half the price of metal. I've noticed no difference with tuning or performance. Of course they won't corrode. I've been using them almost exclusively for a couple of years now, except on the new G250Vs I build, no issues to report. If they are good enough for the S620X-Ti they are good enough for me.