Scubapro 'insulating sleeve' for 109 to BA? Just curious...

[Aloha Joe]

There's enough info here to prove it's not 'needed' so this more for those of us who like to tinker:

I'm a bit surprised a search didn't turn up much on this: why little/no mention of the insulating sleeve when upgrading 109s?

Scubapro lists the sleeve (PN 11500024) in the diagram for G260 and in Bulletin #266 for G250 HP Upgrade. Both use the 'curly foot' lever (aka ears, tabs, feet, etc.) so this might be an improvement on how the lever interacts with the barrel.

I just installed a new curly foot lever while doing a 109/BA upgrade and there was plenty of barrel/lever clearance. The main reason for my investigation though is a slight 'step change' in breathing of my upgraded 109 which existed with old parts and with all new parts, so I'm thinking the barrel might be slightly worn where the lever engages. Maybe if the sleeve centers and prevents the lever from leaning, it can help with smoothness and long term wear?

I ordered a pair of these sleeves. My plan is to perform the BA upgrade to 109 #2 and compare, then add the sleeve to #1 and see if it helps. I'll let you know what I find

 

[Couv]

IIRC @halocline had a similar issue with one of his BA/109s The fix involved a very fine file to re-square the lever broaches. Hopefully, he'll chime in with the correct story.

In the meantime, have you ensured the inside of the air barrel is impeccably clean?

 

[rsingler]

Regs with the sleeve have slightly different barrel dimensions than the original 109. In addition, there's no centering detent to hold the sleeve in the correct position. I would be very wary of trying to fit one on a 109.

Yes, they were designed to eliminate exactly the problem you outline, but @couv 's suggestion to square the hole with a fine file is the better approach. Corrosion at the corner due to dissimilar metals is the problem.