New life for an old MK3

[redacted]

Is the rubber purge botton the same in a 108 as a 109?
So far after soaking the parts everything is looking great. The exhaust T will work, there one small crack in it but I think neoprene wetsuit glue will fix that.
The blue silicone diaphram looks to be in OK shape and useable. I flipped both soft seats. Both hard seats look to be in great shape with no pitting on the edges.
Basically all I need is a rubber purge button an O rings. Brother Couv is going to help me out with some stuff (we need a salom smiley).
I guess I need to get in on the group buy if this metal SP habit keeps up. And I thought collecting double hoses was the evil habit to watch out for! :shocked2:

All parts on the front of the case are interchangeable with the 108/109/156.

Have you looked at a Pilot yet?

 

[Eric Sedletzky]

All parts on the front of the case are interchangeable with the 108/109/156.

Have you looked at a Pilot yet?

A pilot?

 

[redacted]

A pilot?

Second

The original version had a pilot valve that apparently was too complex for many techs to service. It was then "upgraded" to a coaxial valve which takes the same service kit as the D-series and performs similarly (maybe a bit better due to the very large exhaust valve. They are usually a bit more pricey than the 109/156 and replacement diaphragms (exhaust valves) are hard to come by.

You're hooked.

 

[Zung]

So complex Pete Wolfinger made it the final test to close the section on regulator theory in his "Regulator Savvy" book, page 94-102.

Nobody passed the test.

 

[Couv]

I think DA, Matt, and Awap could rebuild and tune those Pilots and Scrotums with their eyes closed. Did one of you guys snap up that Pilot recently on eBay?

 

[superstar]

My first BC was the Scubapro BCP. It was given to me in exchange for work on I did on a dive boat. The air bladder got soo bad it disintegrated so I stuck a Deep Outdoor bladder on it. I still use the BC.

 

[AFdivedoc]

I realize this thread is several months old now, and the recent discussion centered on reconditioning the 108 second stage, but I recently found another way to put those old Mk 2s and Mk 3s back in to service. I came into possession of a couple of these old regs with only 2 LP ports, one HP port, the older low pressure yoke, and the flat filters. I figured they would make dandy deco regs if I could convert them to DIN along with the overhaul. The current SP DIN converter won't work because the regs have a non-removable piece the yoke fits on vs the screw-in adapter with the conical sintered filter seen nowadays.

What modern regs still use flat filters, have a similar yoke attachment and have a currently available DIN converter? Sherwoods do! I had one of the DIN fittings lying around and tried it--it works perfectly, and I did some shallow water testing before using the Mk3 on my deco bottle the other day. It is perfect for this purpose and performs as well as my newer Mk2s. A friend had a 2 more Sherwood DIN converters I was able to get for cheap, and they went on a couple of older Mk2s. Had to get an adapter for the HP hose, since these regs take 3/8 HP fittings vs 7/16.

 

[DA Aquamaster]

The Pilot has lots of little pieces but once you understand it it's possible to tune it. I'd never call it easy as they are pretty sensitive. one issue I noted is that you need to use a mouthpiece with pretty thick bite tabs, especially if you have large
front teeth. If there is not enough area to accomodate the substantial air flow, the Pilot will chatter at depth.

Scubapro had an Air 1 conversion kit for the Pilot that gave it Air 1 internal parts. They are a lot easier to tune and offer about 95% of Pilot performance with less complication. I still have an unused conversion kit in need of a Pilot.

 

[DA Aquamaster]

Hey, you got me curious too, so I downloaded all the SP catalogs from here. I'm old, but not that old to speak with any kind of authority about things that dated back to the early 60's: I was only a boy then.

Anyway, here's what I found:

• Up to '67: there was only 1 second stage packaged together with the first stages, and the packages were called by the first stage name. The second stage looked A LOT like what's known now as the "108"
• In 1970, the "Adjustable" appeared, and was christianed "109", which is the catalog number.
• Only in '77, along with the appearance of the Pilot, the "Second Stage Downstream" got its now-official name of "108" (cat. no.)
• Finally, in '80, each package got a "fully qualified" name, i.e.: "MK III AND 108 REGULATOR"

Another thing: there are 2 kinds of 108's: one without the orifice and one with. Whether there's an impact on performance I don't know.

Maybe an elderly guru can confirm the performance problem you mention is from the 1st stage, or from some grossly mis-aligned units?

By the way, and sorry for a slight hijack: isn't this a beautiful BP/W? It's from the '76 catalog:

I learned to dive with one of these - purchased used in the early 80's. I think they were a mid 70's design - I'll check the catalogs tonight to see when they first appeared. I upgraded mine with the soft band to replace the metal band as it was lighter, a lot easier to pack in a dive bag and was less snag prone, and then ended up using it with doubles anyway.

The hole centers were not the current 11' centers, but otherwise it was basically the equivalent of a modern "hog" BP/Wing. The inflator hose was too long but it could be replaced with a shorter one as the diameter was stanbard, and the inflator used a proprietary QD fitting, but again could be replaced - and the later version of the fitting fit on the end of any LP reg hose. In the late 80s everyone started adopting a common QD fitting that was almost identical to the one used on the by then doiscontinued Watergill AtPac.

I dove my Scubapro Buoyancy Control pack until I wore it out (the seams had a tendency to leak), then I endured a stab jacket for several years before wings became generally available again.

 

[Couv]

Larry,

It's a good thing you wore out that bladder. It's a KNOWN FACT that those type of back mounted devices would hold an unconscious diver face down and drown them.

c