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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
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Goodlifedivers
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Options for leaking Nemrod Snark III

Fri Jan 29, 2016 1:14 pm

I have a Snark III Silver that I have rebuilt. It breathes fine, IP pressure is steady but I have a leak in the OPV, which I gather is common with these regulators.

I tried screwing the valve down all the way but can't get it to stop leaking, although its a very small and slow leak.

What are some options for this reg?

Keep diving it even though its a tiny leak?
Put a LP hose on the port and take the chance of a HP leak?
Modern OPV?

standard US hoses screw fine into the OPV port so no adapter is needed.

What do y'all think?

I have already been in contact with Enrique but nothing has come from it as far as parts.

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Herman
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Re: Options for leaking Nemrod Snark III

Fri Jan 29, 2016 5:40 pm

The OPV port is NOT impedrial/SAE, it's metric....I forget exactly what pitch and diameter. It is close to 3/8 but not close enough that I would try to make it work. It uses a gasket to seal the OPV, not an oring and it's not a standard scuba hose fitting so you will have to get creative if you want to use it.
Herman

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Goodlifedivers
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Re: Options for leaking Nemrod Snark III

Tue Feb 02, 2016 12:59 am

Any serious issues you see with diving with a tiny leak coming from it then?

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SurfLung
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Re: Options for leaking Nemrod Snark III

Tue Feb 02, 2016 4:00 pm

- I've got 2 old Snark IIIs and neither of them leaks... So, there's my two cents on how common it might be to these regulators. I cleaned them both to be sure the OPV had a smooth seat front and back... Maybe that would help in your case.
- On the other hand: As I understand it, the Over Pressure Valve (OPV) is there to protect you from a leak in your 1st stage valve seat. The upstream 2nd stage valve can't release excess pressure like the down stream 2nd stage on DAAMs. So the Snark III OPV is there to give that pressure release. In other words, if the OPV is leaking, it could be telling you that your high pressure 1st stage seat is leaking.
- I realize you said the IP holds steady which suggest there's nothing wrong with the 1st stage seat. But if you didn't have the IP pressure gauge to check it, the evidence would be pointing to a leak in the 1st stage seat. I would check and maybe re-face that 1st stage seat.
SurfLung
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.

swimjim
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Re: Options for leaking Nemrod Snark III

Tue Feb 02, 2016 4:34 pm

My attempts at refacing a Nemrod HP seat were shall we say less then desirable. That would be my last ditch option. JMHO

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Goodlifedivers
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Re: Options for leaking Nemrod Snark III

Tue Feb 02, 2016 8:24 pm

I have two of them a V2 and Snark III. I didn't open up the HP area on the V2 cause I figured if it didn't leak before I messed with it, I don't have a way of fixing them if I do screw it up.

I'm editing this post since I corrected myself.

The V2 doesn't leak. I was able to screw down far enough on the OPV that it stopped and putting it back on the tank tonight with alittle soapy water shows that it's fine.

I was able to get an OPV from another V2 that my local dive shop had hang on their wall. We cleaned it up in the ultrasonic cleaner and I threw that in the reg to see if It wouldn't leak but still had a small leak even cranked down. I then followed your advice and took the OPV apart again, giving it a really good wiping down with a q-tip and blew everything in there out. Lubed up the old O-ring and she is snug up and not leaking.

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