SP 108 cover/lever/diaphragm

[halocline]

I recently rebuilt a 108 I had lying around, this is actually the first 108 I'd worked on. I expected the lever to be similar to the r190 lever, but instead it's straighter and lower profile. The diaphragm has a large flat surface in the middle, sort of like a smaller doublehose diaphragm, instead of the more conical shape on the 109. Consequently there's quite a bit of distance (maybe 3/8") between the diaphragm and cover, and the cover has a rim around the logo plate on the diaphragm side that extends inward to contact the diaphragm.

This is a different cover than the one for the 109. The only schematic I found for the 108 shows the same part no. Does anyone (DA or Couv maybe?) know if the 108 cover is still available? If not, is it possible to retrofit a newer style lever, diaphragm, and cover?

I was pleasantly surprised at how well this reg breathes, since its a fixed orifice I hadn't given it much thought, but now I will definitely use it. I could simply put a 109 cover on it, ( I have a used one on there now) but the extra space between the cover and diaphragm makes the purge quite a bit less responsive.

 

[Zung]

They're different indeed.

Here's the cover, with an extended center ridge to press against the diaphragm:

and the diaphragm, right:

PM me.

 

[Manow]

Interesting post. I have the same issue. I have two SP 108s. The diaphragms are okay, but the covers are rotted pretty bad. These seconds are otherwise in really nice shape. Does anyone know if these covers available?

 

[halocline]

Zung, you are indeed the swiss master. That cover is exactly the one I'm looking for. The diaphragm looks a little different but it might be the angle. Mine is pretty flat in the middle, with a concave curve around the edge.

As usual, this board is a great source of collective information.

 

[ams511]

I was looking at the ScubaPro Museum and wonder if the covers have changed over time. The center logo is almost flush with the ring in the middle. Now look at this photo: See how deep the center logo is in. At first I thought the cover was installed backwards but looking at what Zung posted it does not seem likely.

 

[Zung]

Here's the head side of the diaphragm; halo, is it the one you're after?



It can be stretched to fit a 109/156, but it's a tight fit, too tight for my liking, so I assume it's for the 108 to go along with the special cover.

 

[halocline]

Yes, that's the diaphragm exactly, except mine is yellow. Mine appears to be in pretty good shape.

ams511, the covers for the 109 did change; I know of three different styles. The earliest had five round holes and a small rim around the logo plate, the middle had the same holes but the high rim, (those are the two in your photos) the late had oval holes; that's the one currently available. I suspect it was original on the balanced/adjustable. The latest one works on all 109s; most of mine have new covers. They're all different than the 108 cover, which is functionally different to accommodate the different diaphragm. I'm sure a 109 cover works on the 108, because I'm currently using one, but the purge is less responsive.

With so many 109s around (it was a hugely successful design) I've never bothered with the 108. I just have one because it was included in a purchase of some other stuff. I was really surprised at how well it breathes; better than my current R190s, even though they have adjustable orifices. I used one of awap's homemade seats on it; worked really well. That puts my rebuild cost at about 5 cents.

 

[Zung]

Here are the pics:
Upper left: high rim - Upper right: low rim
Lower left: 108 - Lower right: current, square hole

 

[ams511]

Zung, where do you get this stuff? You seem to know and have everything.

 

[Zung]

Easy

• Diaphragm: eBay Germany
• 2 upper covers: old stock from a LDS
• Lower left cover: gift
• Lower right cover: from my brother couv's group buy

Just keep watching and you'll eventually get them.
But then LDS's are not that stiff over here, nor are the lawers that greedy.