Scubapro 109 Lever Height, Take 2

[Zung]

This is a continuation of a previous thread.

I just ran across a nice SP catalog from 1988 here. There's a cutaway drawing of the 109, page 41, probably not 100% to scale, but when I put the real thing on top of it, it's close, really close. Here it is:

Assuming the drawing is to scale, we can see the lever sticking out about 8 mm or .3".

And here are my 3 109's, all tuned to the lowest possible cracking pressure just before any instabilities:

The lever heights are comparable to that of the drawing.
So the conclusion is: the "standard" lever height should be slightly above the rim of the body.

Any comments?

 

[Couv]

Brother,

In the drawing the purge button is depressed (or ambient is greater than case pressure.) Note the separating between the hard and soft seats. Therefore, the lever is not at it's full height.

I know you know this & it makes no difference to the subject at hand, but just a nick picking note for the Un-usual Suspects; that is a Balanced Adjustable not a 109 as it has a flow through poppet and balance chamber.

Cool drawing though, thanks for posting it.

c

 

[halocline]

Well, to nit-pick Couv's nit-picking, the true "balanced adjustable" had those words engraved on the front of the case. (I really need to get a life) We can't see if that's what's in the drawing.

It looks like the first of your three regs has the newer lever. The lever comes up at a steeper angle, but the fingers on the lever are set at a sharper angle which compensates. The middle one looks like the oldest lever. I would not characterize the lever height in any of them as "slightly" above the rim of the reg, to me that's quite a bit above the rim. It looks normal to me. I bet the top one breathes the best, doesn't it? I like the new lever with the curved feet.

 

[Couv]

... I like the new lever with the curved feet.

Si; new lever and s-wing poppet. Easy to tune, no feet slippage like some of the other combinations.

c

 

[DA Aquamaster]

I think people are over thinking it. The R109 and R156 are single adjustment designs. This refers to a single adjustment for both orifice depth and lever height. As such the lever height is determined by the relationships of the orifice, seat and poppet. Add a thicker or thinner seat and you have issues, try to work with an overly worn (effectively, to thin a seat) and you have issues.

In essence, if the parts are correct the spring pressure is correct and the orifice is properly set, the lever height will be correct. In the vast majority of cases, when I set the orifice in either reg (R109 or an R156) just short of freeflow (with the adjustment knob all the way out) the lever height will be correct. What matters here is that the reg begins to purge within about 1/16" -1/8" of depression of the purge.

There is no doubt some correct number of milimeters of of lever protrusion above the case but I don't know what that is nor do I care. What matters is that I need to screw the orifice back 1.5 turns from the bottom to be in the adjustment ballpark and from that start position it is normally less than a 1/4 turn to achieve the final adjustment with the correct lever height.

 

[Zung]

Thanks for your comments, valuable as usual.

Nit Picker #1: mon frère, it is actually a BA, my bad.

Nit Picker #2: Good eyes, Matt, I didn't notice that before, but you're right, as usual. Actually the legs of all the levers are the same, the middle one with a step in couv's picture. One fork is slightly different. The toppest one is the only one I dove with; I just finished the 2 others, but it's gonna be a long wait until the waters hit the 70's :-(

DA: you're right, as usual. It's just some recent questions around the lever height got me into (over-)thinking, and that catalog is just beautiful!