Urgent servicing help needed! (SP Mk10)

[Pavel Spirine]

Hi everyone,

My dad's getting ready to leave for the Maldives soon and went to get a recently purchased Mk10 G200b/G250 combination serviced. Problem is the LDS said that the 2 2nd stages aren't a problem, however they don't have a Mk10 kit in stock.

My question is, are there any other kits from SP (Mk5, Mk10 plus, Mk15, Mk20, Mk25) that are interchangeable? From what I understand the Mk10 doesn't have very many plastic/non-generic parts?

I did search for this but couldn't find the answer after 30 minutes!

Thank you

Pavel

P.S. what IS the difference between Mk10 and Mk10+ ?

 

[DA Aquamaster]

Piston Stem o-ring:

The piston stem o-ring is the same one used in the Mk 20/25.

The o-ring that seals the interface of the Yoke or DIN retainer and the reg body is also the same o-ring used for the same purpose in the Mk 20/25/17, etc.

Piston Head O-ring

The piston head o-ring is different than any other piston head o-ring in current use (other than the Mk 10 plus) but I'd have to check the part numbers to see what other applications the Mk 10 piston head o-ring may be used for and what other kit or bin an LDS could borrow one from. (Of course, your LDS can check the part numbers as well and make the same determination, or they could call tech services and get the answer.)

High Pressure Seat:

The seat is identical to the seat used in the Mk 5 and TUSA has a Mk 10 clone that could donate a seat (or an entire service kit if they are a TUSA dealer. More importantly though, SP has included three seats in each Mk 10 kit for years to allow more IP range adjustment and I have yet to see an SP shop does not have piles of extea Mk 10 seat laying around.

Filter and retainer:

These are standard SP parts that can be found in any kit.

Other parts:

There is a red washer used to seal between the seat and reg body that also ensures the seat stays in place, but reusing that woudl not result in reg failure and its used to be done with an off the shelf o-ring of suitabel diameter whihc would still work fine.

The other parts are all o-rings that are stock items and are also mostly statuc o-rings that are not normally replaced annually.

The Mk 10 Plus kit would be the first place I would go digging for parts as the only differences are in the seat related parts as the Mk 10 Plus uses a different seat and seat carrier. The piston in the Mk 10 Plus is also different in that it uses a rounded seating edge, but the piston head and piston stem o-rings are the same.

 

[Pavel Spirine]

Great, thanks that's exactly what I was after! Info has been passed on

Do you know the model of the TUSA clone?

Also, is a MK10+ significantly better (performance wise) than a standard Mk10? (is it possible/recommended to upgrade? no cold water diving for me if that's an issue!)

 

[halocline]

So that's what that red washer is for. I recently bought two MK10 kits; one new at my LDS, one "new" on ebay. The ebay kit does not have the red washer, but it does have a purple o-ring that looks to be about the same size and almost certainly is for that purpose. It also has a light blue o-ring, that looks to be just a tiny bit smaller than the amber piston head o-ring. I assume that one seals the turret, but there's nothing like it in the current LDS kit.

How soon is "soon"? If it's today, and you can't find the kit but can get decent quality o-rings locally, the Harlow book lists the size for the piston head o-ring as 017 and piston stem as 010. The piston stem o-ring seals HP air and should be a duro 90, but as DA said, the more current model kits also use this o-ring.

I have not heard of any significant improvements from the MK10 to the MK10+, but there are some threads discussing exactly that if you search.

 

[redacted]

That Mk10 kit with colored o-rings is probably about 10 years old. My '97 schematic show an amber piston o-ring PN 01-050-162 and a blue swivel (turret) o-ring PN 01-050-162. I measured them both out to be the same 2-017. Come to think of it, I've got a blue o-ring on the piston in one of my Mk10s. Want to bet there is an amber one on the swivel? I hate fixin' things that are not broken but I may have to make an exception - looks like rain anyway.

All the Mk10 0-rings are standard sizes and the only one I believe is unique to the Mk10 (among SP regs) is the 2-117 cap o-ring that is normally reused. The piston head o-ring is a 2-017 and is also used in turret swivel of the Mk20/25. The seat retainer, which now uses that red washer, was a 2-013 o-ring which is also used in a number of other SP applications.

I can understand smaller scubapro dealer not maintaining a stock of kits for older regs but I find it hard to believe he does not have a good supply of seats and o-rings laying around. He may be hesitant to replace SP kit o-rings with generic or loose spares, something the DIYer is used to doingthat red I would hope he is not just trying to sell you a new reg.

 

[Couv]

DA and AWAP are right on target. Here is my list in case you want to print it out:

MK 10 o-ring list

HP piston stem -010 (duro 90)
Yoke nut -011
3/8 Hose/plug -010 (duro 75-90)
7/16 Hose/plug -011
1/2 Hose/plug -013
HP seat retainer -013 (or washer)
Tank/regulator valve -014
HP Seat retainer (cap) -015
Piston head -017
Turret swivel -017
Ambient chamber to body -117


You'll notice that the most used o-ring is the -010, to avoid installing the wrong hardness (duro 90) in the piston stem position I buy only duro 90 -010 o-rings and have never had a problem with them installed in plugs, hoses, etc.

 

[halocline]

I don't remember an o-ring between the ambient chamber and the body in my MK 10. Am I missing something? Wouldn't be the first time.

While we're on the topic, those amber o-rings are supposedly polyurethene, I believe. They definitely have a softer feel than the regular nitrile or viton duro 90 o-rings, but they were marketed by SP, according to the Harlow book, as higher performing and more extrusion resistant than what they were using before. My new/old MK 10 kit has them. I wonder if they are any better or worse than the current black o-rings.

 

[redacted]

If that o-ring were not installed, you'd be bubbling thru the threading between the ambient chamber and the body. It is the largest and fattest o-ring in the Mk10 and is seated in a groove in the ambient chamber and crush seals with the body as it is screwed in. All o-rings in the kit except the 010 HP piston o-ring are probably duro 70 or 75. I used some duro 90 polyurethane piston o-rings, based on Harlows book, when I first started and had no complaint except they were fairly expensive. I have one Mk10 that I was playing with today that is producing at least a 10 psi IP difference under 3000 psi supply as opposed to 500 psi. I suspect it is the viton duro 90 o-ring extruding a bit (enough to increase friction but not enough to damage it) making the IP work a little harder to lock it up at higher supply pressures. I believe nitrile may be a bit more resistant to extrusion so I may give an N90 a try there.

 

[halocline]

Is it #26 on the MK 10 schematic? I bet we have the same drawing, mine says rev. M, date 02/01.

 

[redacted]

That's it.