Mk20/R380

[bathbiggles]

Hiya. I have got an opportunity to buy a near new Scubapro mk20 reg setup with r380 second stage and octo. This would be my first reg after about 70 dives. I know its a relatively old model but this one is hardly used but i know hardly anything about it and im getting minimal stuff off google. Was wondering if anyone might have any thoughts on it as i have no idea whether its a good/bad reg. Would be used mainly in warm water - red sea etc.
Cheers
Ben.

 

[onostusis]

I use an R380 with the Mark 16 and love it. I have however seen a Mark 25 (newer version of Mark 20) freeze up and freeflow.

 

[MechDiver]

if anyone might have any thoughts on it as i have no idea whether its a good/bad reg. Would be used mainly in warm water - red sea etc.
Cheers
Ben.

I've had mine at or below 200' a number of times

I would replace the R380 primary with something else, as the R380 is somewhat basis. I have G250 and D500s on my SPs.

The Mk20 is an excellent first stage.

MD

 

[DA Aquamaster]

The only significant difference between a MK 25 and a Mk 20 is the addition of a new seat retainer in the Mk 25 that allows external IP adjustment. And newer Mk25's (after June 2003, have the full AF kit. All of this however is retrofittable into any Mk 20.

The Mk 20 you are considering may have one of 3 pistons in it - The original knife edged piston, the mid production brass tipped rounded piston or the latest composite piston. The mid production pistons can be problematic as they have a less solid intermediate pressure lockup and in some cases can have IP creep. But parts cost for a new composite piston is about $20.00 so an upgrade is not a big issue.

In short - great first stage. The R-380 is also a reliable first stage capable of excellent performance and is well suited to recreational diving. A G250, G550, S600 or X650 could be added in the future to get even more performance in more technical pursuits.

 

[bathbiggles]

its about 18 months old apparently - what piston type will be in it i dont know - any ideas? but sounds like i should be prepared to upgrade it then. thanks for your help!

 

[DA Aquamaster]

You can tell if it's the mid production brass tipped piston with an IP gauge by how the IP lockup occurs over several seconds rather than immediately - a remotely knowledgeable SP tech could tell you after doing a flow test ( a good idea on any used reg).

A piston upgrade is not really needed unless you encounter problems. However the new composite piston is part of the anti-freeze kit as the composite head helps reduce ice formation as does the mirror polished piston stem so if you are using it in cold water, the new piston may be worth installing at the next annual service anyway.

You could also consider upgrading to the newer finned swivel cap used on the latest Mk 25. Dealer cost for this part is also in the $20-$25 range.

I would not bother with upgrading the seat retainer to Mk 25 status. The change just makes it easier for a tech to adjust the intermediate pressure after the reg is serviced and it really has no benefit to the diver.

 

[bathbiggles]

great. ive bought it. ill look into the piston upgrade as i am getting interested in cold water diving - thanks for your help. Ive heard the second stage is like a skoda engine in a porsche :06: so might be upgrading that one shortly!

 

[DA Aquamaster]

great. ive bought it. ill look into the piston upgrade as i am getting interested in cold water diving - thanks for your help. Ive heard the second stage is like a skoda engine in a porsche :06: so might be upgrading that one shortly!

Air flow wise the R380 is ok, but it needs to be tuned lighter than factory spec to really perform (around .8 to 1.0 inches of water) in terms of breathing resistance. It is certainly capable of that type of perfromance but it then makes it more suscpetible to freeflow in some circumstances as the cracking adjustment is not diver adjustable.

So I would agree a G250 or other balanced and adjustable second stage is the way to go.

 

[moxie]

I'd replace one of the 380s with a 250 as the primary second stage and use the other 380 as your octo (safe second). This will result in a really sweet setup, but there's really nothing wrong with it as is. Good luck.