D420! How about that?

[halocline]

Thank you very much for your video . As you well know ( because you rebuilt mine ) the pilot to be in tune leaks 6 bubbles a minute

What they say is that a very slow leak is acceptable, not that it's specified. I was able to get my pilot tuned without any leaking. It's a matter of being very careful, actually lucky when it comes down to it, with the alignment of that tiny o-ring on that button. It took me several tries to get it right. That tiny o-ring is originally neoprene if I remember and I used silicone duro 50 or something like that. It's been a few years.

 

[diver0004]

I apologize for my interpretation of the data .

 

[rsingler]

The "acceptable leak" standard is a function of the fact that the Pilot has a second knife edge buried inside the poppet stem on a press-fit cone.
It's part of the servo mechanism; it can't be disassembled, and it can't be polished.
You can see the cone through the hole at the arrow, and the servo rod at the left.

After 50 years, some deterioration of that cone is inevitable, and @halocline has the correct solution: the softest duro o-ring that you can find for that tiny seal. The o-ring is 1mm ID!
Halo is a lucky guy to have a no-leak Pilot, but as long as the main LP seat isn't the source of the leak, it's of no consequence.

 

[halocline]

I apologize for my interpretation of the data .

Don't worry about it. If it were necessary to apologize every time we posted something not 100% accurate we'd all be in trouble.

 

[buddhasummer]

Don't worry about it. If it were necessary to apologize every time we posted something not 100% accurate we'd all be in trouble.

and it'd be a very quiet forum.

 

[buddhasummer]

Service kits are a bit spendy at around $34. The Venturi decal is not apparently available as a separate item which seems strange given it needs to be removed if you want to adjust cracking. I guess SP don't want you to do that.

@rsingler is the decal re usable? Any chance you could post a photo Rob of the top without the decal? Thanks a bunch in advance. Cheers.

 

[lexvil]

Service kits are a bit spendy at around $34. The Venturi decal is not apparently available as a separate item which seems strange given it needs to be removed if you want to adjust cracking. I guess SP don't want you to do that. @rsingler is the decal re usable? Any chance you could post a photo Rob of the top without the decal? Thanks a bunch in advance. Cheers.

Considering the service kit replaces so many important parts $34 isn’t bad, I would just leave the sticker off or maybe poke a hole in it.

 

[buddhasummer]

True. I did consider poking a hole.

 

[rsingler]

Here's a pic of the D420 without the top decal. The decal is fairly heavy foil, and will come off without bending, if you're judicious. So it could easily be reused. A half-inch hole would expose the hex. A smaller one would allow just the key to fit in, but would serve as a water collection point in the recess for that screw. It's not too ugly without any decal at all.

 

[Angelo Farina]

What about a mod with a knob permanently fitted in the hex hole, so the diver can adjust the cracking pressure while diving, as in my favourite 109/156 second stages?