Scubapro S109 BA conversion not going well

[davehicks]

I am working a couple of ScubaPro 109s and trying to update them to Balanced Adjustable. The reg bodies are in fair shape, with just some light scratches on the chrome. I took them apart, cleaned them up, and spent some time polishing the chrome with a dremel. The exhaust valve crumbled to bit, but I was able to improvise one from some other spares I had.

I got the BA parts recently from @buddhasummer including:

• 01.020.216 G250V
• 11.159.102p Long crown balance chamber
• 11.250.141 G250V lever
• Swing poppet from a G250V kit

I'm using the original brass orifice. I put it all together and the level/spring tension is super tight. I adjusted the orifice and hooked it to a tank. When it was dialed in to barely leaking and knob full out, it breathes really hard. Magnehelic guage read over 4 inches!

Any ideas about what the problem might be? Seems like maybe the spring is too strong?

 

[Nemrod]

You need a different spring. Is the spring you are using the Balanced Adjustable spring or from the (non-balanced) Adjustable spring?

 

[Kupu]

I doubt the spring is the issue. Although there is often slight manufacturing variation in one spring to the next, 01.020.216 is correct.

The 109 spring pad was not reinstalled? Including the pad after conversion would bump up the lever/spring tension.

 

[davehicks]

I doubt the spring is the issue. Although there is often slight manufacturing variation in one spring to the next, 01.020.216 is correct.

The 109 spring pad was not reinstalled? Including the pad after conversion would bump up the lever/spring tension.

No, I didn't use the spring pad/spacer that was present in original unbalanced configuration.

 

[rhwestfall]

Poppet installed upside down?

 

[lexvil]

It’s seems to be the nature of the 109, 20 will turn out perfectly and wants to retire, never came up with a consistent cause, it can be any one of the components or the lever feet openings in the barrel, if you have a second working one to switch parts around with it’s easier to isolate the cause.

I no longer waste my time with them.

 

[rhwestfall]

I discovered there are different height orifices that can play a role too.

It can be frustrating....

 

[Boarderguy]

Is this both of them or just the one?

 

[davehicks]

Is this both of them or just the one?

Just one so far. I'll play with it some more today and try to figure it out. If it doesn't click, then I will pop the parts in the second one before I do the full spit and polish on it.

 

[davehicks]

Here is what seems to be the problem:

The original parts (spring, spacer, poppet, seat) are about 5mm shorter than the updated spring, balance chamber, s-wing poppet, and seat. The new parts have too much spring pressure. The orifice actually cut a donut out of my new seat on the s-wing.

Something is out of spec here. I need a shorter spring or poppet.