I just got an older steel 72 with a j-valve on it (in hydro), and wondered if I can replace it with a standard k-valve, or if this tank is threaded differently than more modern tanks.
replacing j-valve on steel 72
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FredT
Guest
Most J valves with an o-ring seal have the 3/4-14" straight pipe threads.
A very few have 1/2" straight pipe threads, and a few more have 1/2" NGT.
If you can't see threads at the base of the valve when it's mouted on the tank it's probably 3/4" straight pipe, the same threads as on most current tanks sold in the US. If you remove the valve and have a measurement across the thread of a bit over 1", it's a 3/4"-14 valve.
Of course the best thing to do is just dive it as is. J valves make great carrying handles.
FT
A very few have 1/2" straight pipe threads, and a few more have 1/2" NGT.
If you can't see threads at the base of the valve when it's mouted on the tank it's probably 3/4" straight pipe, the same threads as on most current tanks sold in the US. If you remove the valve and have a measurement across the thread of a bit over 1", it's a 3/4"-14 valve.
Of course the best thing to do is just dive it as is. J valves make great carrying handles.
FT
Depends on the tank. How old is it? Why bother replacing the valve? As long as it's in good shape, leave it down and it is a K valve.
Don Burke
Contributor
Some of the 72s have a half inch thread. I have four that have the standard 3/4 inch thread and they mounted right up to isolation manifolds.
Unless there is some compelling reason to change it, using the existing valve is probably your best option. If you have your heart set on a K valve, finding a half inch one may take some looking.
Some J valves can be changed internally to defeat the reserve function.
Your mileage may vary.
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