Difference between SP Mk10 and Mk10 plus?

[Kncaffrey]

Hello,

I pretty much stick with G250 as my second stage of choice, but I was wondering something. I have an Mk25 and an Mk10. They both breathe the same down to 130' (the deepest I have been)...there really is no difference at all. In fact, I have heard lots of folks comment that they breathe the same down past 250'. OK, before anyone jumps on me about SP performing poorly in cold water, let me say that I don't care. The only way anyone is going to get me in water that is colder than 55 degrees is if they push me in when I am drunk.

Now I am also beginning to work (carefully/methodically) on my own regs, and acquiring all the necessary tools/knowledge. I am going to buy a backup reg set, and I figure I'll just get an Mk10 because it is easier to work on...many fewer parts...cheaper, and qualitatively identical. I can feel myself quickly becoming one of those "all this new plastic crap isn't as good as the older tried and true gear" guys...

What I have never been able to get a straight answer on is this: what the heck is the difference between an Mk10 and an Mk10 plus? And is one substantially different to work on than another? Is one more dependable than the other? Anyway, thanks for the help.

Oh, yeah, I should ask while I am here...anyone have recent updates on where I might be able to get a supply of service kits for SP regs? A list of the O-ring size/types that I should buy for the Mk10 and Mk25? I have the diagrams and I am getting the Vance Harlow book soon.

KC

 

[oxyhacker]

The MK10+ was a sort of ******* interim measure while SP was shifting production abroad and having probs with the Mk15. The main difference was it had the new rounded-end piston like the Mk20 instead of the traditional knife-edge. To keep the piston/spring aligned they replaced the shims that normally go under the spring with a guide bushing which is supposed to be replaced yearly, then put the shims under a revised HP seat holder.

Nothing wrong with the 10+, some folk here have them and like them very much, but I personally have no problems with the plain ol' 10 and was never sure what the point of the whole exercise was.

Hello,

I pretty much stick with G250 as my second stage of choice, but I was wondering something. I have an Mk25 and an Mk10. They both breathe the same down to 130' (the deepest I have been)...there really is no difference at all. In fact, I have heard lots of folks comment that they breathe the same down past 250'. OK, before anyone jumps on me about SP performing poorly in cold water, let me say that I don't care. The only way anyone is going to get me in water that is colder than 55 degrees is if they push me in when I am drunk.

Now I am also beginning to work (carefully/methodically) on my own regs, and acquiring all the necessary tools/knowledge. I am going to buy a backup reg set, and I figure I'll just get an Mk10 because it is easier to work on...many fewer parts...cheaper, and qualitatively identical. I can feel myself quickly becoming one of those "all this new plastic crap isn't as good as the older tried and true gear" guys...

What I have never been able to get a straight answer on is this: what the heck is the difference between an Mk10 and an Mk10 plus? And is one substantially different to work on than another? Is one more dependable than the other? Anyway, thanks for the help.

Oh, yeah, I should ask while I am here...anyone have recent updates on where I might be able to get a supply of service kits for SP regs? A list of the O-ring size/types that I should buy for the Mk10 and Mk25? I have the diagrams and I am getting the Vance Harlow book soon.

KC

 

[DA Aquamaster]

As indicated above, the Mk 10 Plus uses a mk 20 style piston with a rounded sealing edge and the newer Mk 20 style concave seat as well as a new seat retainer.

The rounded sealing edge and concave seat allow more airflow through the piston and flow performance is improved. And like the Mk 20, this is not something you will ever notice. SP sold (and still sells) upgrade kits so that Mk 10's can be upgraded to Mk 10 Plus status.

My initial experience with the Mk 10 Plus shortly after it was introduced was not good as I could never get a full season out of the newer seats and I converted mine back to Mk 10 status. However the seat material has been changed and I have not had any problems with them recently.

The Mk 10 Plus still uses the rounded piston while SP went back to knife edged pistons on late production Mk 20's and on the Mk 25. Consequently the Mk 10 Plus has the same creepy IP lockup traits as the mid production Mk 20's with the rounded sealing edge pistons. It does increase airflow a bit but is, in my opinion, not worth the cost of the upgrade kit. If for some reason you need a new piston in your Mk 10 anyway, it's probably worth it, but if your Mk 10 is not broke I would not bother to ugrade it.

 

[Kncaffrey]

That helps me understand more about what I am getting into. I just ordered Vance Harlow's book from www.airspeedpress.com and should get it fairly soon. I hear that the Mk10 appears in there ocasionally. I also got Vance to send me a list of the O-ring sizes required for the Mk25 (nice guy...he had the list close to hand and sent it on!), an issue that was bugging me because it is harder to work on than the Mk10. Now once I get the book I'll start to assemble the basic tools necessary for doing the job and then start the real learning curve.

Thanks again,

Kevin

 

[mojito]

i have a mk10, will try it when i get an alternate second stage fitted, and here is my question.

1. Can I fit any manufactures second stage? I seem to remember that intermediate pressure is different.

2. I also would like to know what else other than the gauges would connect to the high pressure ports. The low pressure ports dont seem to be labelled just the HP ones.

thank you for helping a newbie

mojito

 

[DA Aquamaster]

i have a mk10, will try it when i get an alternate second stage fitted, and here is my question.

1. Can I fit any manufactures second stage? I seem to remember that intermediate pressure is different.

The first stage IP range for nearly every manufacturer is approximately 120 to 145 psi. The Mk 10 is a balanced first stage and the IP is fairly stable as the tank pressure falls from full to empty.

The good news is that most alternate second stages sold as alternate second stages have a higher than normal cracking effort of a least 2.0" inches of water. This both reduces the risk of an inadvertant free flow and makes them more likely to be compatible out of the box with just about any first stage.

The average octo is a standard down stream dual adjustment design and the increased cracking effort is obtained by tightening the orifice. This means they should work without further adjustment even if matched with a first stage at the upper end of the IP range.

The bad news is that you may not like an octo that breathes like a rock and you may want to take it in and have it tuned to your specific first stage. If you buy the octo from a dealer, they should do this for you for free.

2. I also would like to know what else other than the gauges would connect to the high pressure ports. The low pressure ports dont seem to be labelled just the HP ones.

The Mk 10 is normally mounted with the low pressure port swivel cap pointing down. But with some tank/valve combinations there may not be enough clearence, so the other HP port allows the reg to be pointed "up" while still allowing the HP hose to be routed to the diver's left side.

In some rare cases a diver may choose to use a transducer for an air integrated computer and still use a backup mechanical SPG so both ports may be used.

Other than HP hoses/transducers for SPG's of one type or another, there are no other accessories that are attached to the HP section of the regulator.

Nobody marks low pressure ports so if it is not marked "HP" it can be assumed to be a low pressure port. HP ports on any first stage made in the last 25-30 years also use a larger diameter hose to prevent the diver from inadvertantly attaching a second stage or low pressure inflator hose to an HP port.

 

[mojito]

thanks very much, I think i understand all that I need to from that. It did look strange at first the configuration of the mk10's ports, nice that the IP ones (sorry not Low pressure) rotate. I moved the SPG to the lower HP, it does fit, and then my second stage attaches off the end of the IP ports. The only stretch one is the low pressure inflator, but that is the jacket that feels the stretch not my mouth!
thanks ,im off to find an octo now.
mojito

 

[coldstroke]

Hello,

I pretty much stick with G250 as my second stage of choice, but I was wondering something. I have an Mk25 and an Mk10. They both breathe the same down to 130' (the deepest I have been)...there really is no difference at all. In fact, I have heard lots of folks comment that they breathe the same down past 250'. OK, before anyone jumps on me about SP performing poorly in cold water, let me say that I don't care. The only way anyone is going to get me in water that is colder than 55 degrees is if they push me in when I am drunk.

Now I am also beginning to work (carefully/methodically) on my own regs, and acquiring all the necessary tools/knowledge. I am going to buy a backup reg set, and I figure I'll just get an Mk10 because it is easier to work on...many fewer parts...cheaper, and qualitatively identical. I can feel myself quickly becoming one of those "all this new plastic crap isn't as good as the older tried and true gear" guys...

What I have never been able to get a straight answer on is this: what the heck is the difference between an Mk10 and an Mk10 plus? And is one substantially different to work on than another? Is one more dependable than the other? Anyway, thanks for the help.

Oh, yeah, I should ask while I am here...anyone have recent updates on where I might be able to get a supply of service kits for SP regs? A list of the O-ring size/types that I should buy for the Mk10 and Mk25? I have the diagrams and I am getting the Vance Harlow book soon.

KC

Can I get a copy of the diagrams or manual for mk10.