Noisy M1 seconds- too hot?

[buddhasummer]

I have some M1 2nds, issue is they are not smooth breathers at all, they stutter, like air flow is changing or at times rushing in, like a faulty turbo car and are quite noisy. Seem a little better at shallower depths or if I breathe softly and gently. As they are,they are almost undiveable to me, the roughness and noises are irritating as hell.

Am wondering if I have them tuned too hot. The lever is set as per manual, just until leak stops and about a MM or 2 in. Cracking I've set to around 1.1".

Any ideas? Advice greatly appreciated.

@Wookie
@Scared Silly
@lexvil
@rsingler

Cheers

 

[buddhasummer]

To add, they are unstable head down position. Given I've tuned then to what I believe to be spec, not sure what's going on. Wondering if I should lower the lever or increase cracking effort or both? Cheers.

 

[buddhasummer]

Could it be something to do with the AFC?

 

[Fibonacci]

Don't think its the AFC unless the thin diaphragm has a small hole or tear in it... the AFC seems to work seamlessly for me.

When first tuning some of my Atomic second stages I had all sorts of issues with them venting copiously for a couple of seconds when pressurised via the (Atomic) first stage... and would then show variable WOB from session to session.

Was driving me nuts till I worked out Atomics are VERY finicky when it comes to lubrication... I was using Dow Corning 111 on these specific parts (thinking it would offer more corrosion resistance) instead of Christolube or my preference Tribolube 71.
I used Tribolube 71 everywhere else...

The Orifice (#02-0034-SS) and the Wave Spring (#02-0033-00) were sticking a bit inside the Orifice Sleeve (#02-0036-00) and Inlet Tube with the fairly thick DC-111 grease. Setting up the Demand Lever to that position meant the WOB drifted later as the parts settled in a slightly different position on next pressurisation.

I cleaned off all the DC-111 and relubed ALL parts with Tribolube 71... problem fixed!
The Orifice and Wave Spring snapped into place consistently on pressurisation, and once the Demand Lever height and cracking point were set they didn't change at all.

 

[happy-diver]

You know what, sometimes I squeeze some grease in the fully assembled barrel
and blow it through

111 is too thick and sticky for moving regulator things

and for tight DSVs

 

[buddhasummer]

Don't think its the AFC unless the thin diaphragm has a small hole or tear in it... the AFC seems to work seamlessly for me.

When first tuning some of my Atomic second stages I had all sorts of issues with them venting copiously for a couple of seconds when pressurised via the (Atomic) first stage... and would then show variable WOB from session to session.

Was driving me nuts till I worked out Atomics are VERY finicky when it comes to lubrication... I was using Dow Corning 111 instead of Christolube or my preference Tribolube 71.

View attachment 522029
The Orifice (#02-0034-SS) and the Wave Spring (#02-0033-00) were sticking a bit inside the Orifice Sleeve (#02-0036-00) and Inlet Tube with the fairly thick DC-111 grease. Setting up the Demand Lever to that position meant the WOB drifted later as the parts settled in a slightly different position on next pressurisation.

I cleaned off all the DC-111 and relubed all parts with Tribolube 71... problem fixed!
The Orifice and Wave Spring snapped into place consistently on pressurisation, and once the Demand Lever height and cracking point were set they didn't change at all.

Thanks Graeme, they were serviced by an Atomic Tech so I'll assume correct lube was used. Hoping someone will chime in with some tuning pointers. I'll try to tune it out first, pun unintended, failing that I'll pull them apart, clean, re lube, install a new seat and try again.

Mine are closing fine on pressurization FWIW.

Had issues with an Atomic first stage out of the box and now issues with second stages, doesn't bode well for a long relationship.

I've successfully serviced G250s/G260s/all Apeks/Conshelfs/156 BAs etc so have no idea what's going on.

As it stands all things considered they are up there with the worst " breathers" I've had. I must be doing something wrong. I can feel their potential, slow, soft, gentle breaths and on occasion they seem to behave as you'd expect.

 

[buddhasummer]

I've got a tank here waiting to try again but don't want to attempt it blind as I'll just end up chasing my tail. I've tuned them as per manual and they are both within spec. Don't want to waste a service kit just throwing one in there in the hope it'll miraculously solve my problem. Something is wrong, I'm just not sure yet as to what. I'll wait for some more info. Cheers.

 

[Wookie]

I can’t speak to DC111 as I have never put it in an Atomic.

I can speak to the chattering you mention, but I only get that if I’m hoovering like a mad fool wrestling a drill rig or a big fish. If that’s happening, I adjust the tuning knob to give me just a touch harder WOB and it stops. Or, I stop, calm down, concentrate on breathing, and it stops. I’ve never had that happen on a pretty reef fish dive.

 

[buddhasummer]

I can’t speak to DC111 as I have never put it in an Atomic.

I can speak to the chattering you mention, but I only get that if I’m hoovering like a mad fool wrestling a drill rig or a big fish. If that’s happening, I adjust the tuning knob to give me just a touch harder WOB and it stops. Or, I stop, calm down, concentrate on breathing, and it stops. I’ve never had that happen on a pretty reef fish dive.

Yeah, I'm easy diving, not heavy breathing at all. In the absence of more information, I've dropped the lever height on both. Went with the G250 method, back out until leak, turn in until just stops and then 1/12 further turn in. See how it goes on tomorrows dive.

So I take it "normally" they aren't stuttery, chattery, noisy breathers? I hope not. Cheers.

 

[rhwestfall]

Maybe follow the tuning of a G250HP/S555/600 (it has the similar multiple point adjustment style "guts")?