You could return it for adjustment or even replacement. It is brand new.
James
James
MK25/G260 whistling
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Yeah, was hoping for an easy fix. The shop I bought it from is in Tokyo which is a ways from my city, language is another issue and the purchase was hidden from my wife so unfortunately I can't ask her to assist but yes, it looks like trying that avenue will be the easiest path for me. I'm sure I can find someone to assist. I did register the regs online with SP so maybe a local shop can assist, I'm not sure if it has to be returned to shop of purchase or if SP cover nation wide. I'll look into it over the next few days.
R
redacted
Guest
While the Mk25 piston is not quite as rounded as the original Mk20 piston it is still a rather dull edge compared to the Mk10 and predecessors. As you should know, those older pistons actually cut a groove into the seat in order to make a seal. The Mk20/25 seat would be destroyed if the piston cut into it. But, as long as using the bullet tool does not interfere with the Mk20/25 assembly tool keeping the bushing/o-rings sandwich in place as the piston is inserted, it should not hurt and might even help keep the sandwich remain intact. But it is not necessary.
What does the Scubapro say? My Mk20 Tech Service Guide and Engineering Bulletin 267 do not mention a bullet tool.
R
redacted
Guest
You might want to check the manual. EB 267 applies to the current composite piston and did not recommend it in that publication.
Ahhhhh, the plot thickens, subterfuge is afoot. In that case I am returning to my secret code name,
N
dfrancos
Registered
halocline
Contributor
Just don't get any lube inside the piston and you'll be fine. Excess lube on the outside of the shaft will get pushed back into the ambient chamber by the bushing and HP o-ring. I believe the excess lube dampens vibrations on the piston, which is usually what causes the whistling. It's a little like a flute, with air rushing past the edge of the piston acting sort-of like someone directing a stream of air across a mouthpiece. So I don't think the whistling is any indication that there's insufficient lubrication on the o-ring for it to work properly, just that there's not enough to dampen the vibration. I've also heard that the spring can start a resonant vibration, but since it's the air vibrating the piston edge that starts the noise, I'm a bit skeptical about that.
The MK20/25 does not need the piston bullet, unless they've changed the piston in the last year or so. I'm sure there are some SP techs that use one, it won't hurt anything, but the SP insertion tool (at least the one I'm aware of) makes it impossible to use a piston bullet. This tool holds the bushings in place while you install the piston, then you remove the tool and install the spring and seat carrier. So you either hold the bushings in place while the piston is being installed, or you use the bullet. Can't do both. I guess if you use the bullet, you could remove it after installing the piston and then use the insertion tool to re-seat the bushings/o-ring if they've moved.
On the older BP regs (MK5/10) you install the o-ring in a machined groove in the reg body, where it is firmly held in place. Then you use the bullet to install the sharp-edged piston, and there was no insertion tool in the way to remove the bullet. On the MK15, where there are bushings and a knife edge piston, there's a circlip that holds the bushings in place, so you can push the piston bullet through without dislodging any bushings.
---------- Post added July 21st, 2015 at 11:13 AM ----------
Maybe they've changed that insertion tool since the ones I've seen.
Anyhow, the seminar you're referring to, is that one of the ones that trains SP techs in one weekend, with no prerequisites, tests, or possibility of failing? I'm not trying to be a jerk, it's just that the manufacturer's repair seminars as I understand them are woefully lacking in rigor, considering it's "life support" we're talking about, correct?
Please don't take offense, I'm sure you are an excellent regulator technician. If only that were the standard.....
Maybe they've changed that insertion tool since the ones I've seen.
Anyhow, the seminar you're referring to, is that one of the ones that trains SP techs in one weekend, with no prerequisites, tests, or possibility of failing? I'm not trying to be a jerk, it's just that the manufacturer's repair seminars as I understand them are woefully lacking in rigor, considering it's "life support" we're talking about, correct?
Please don't take offense, I'm sure you are an excellent regulator technician. If only that were the standard.....
The insertion tool we use in the shop is made of plastic or Teflon,.. not sure which. Looks like the metal ones, but is hollow on the wide end (that holds the o-ring/ bushing assembly in the chamber while pushing the piston through. Yes, the course I did 2 yrs ago was only 2 days, but I had serviced 100's of those regs in the years before I went. My mentor who originally taught me was VERY mechanically inclined (I'm not particularly, but I did learn to do it & do it well). Though the course was short, I did manage to learn a few techniques that made life easier & made things more efficient. The course was taught by the designing engineer of the regulator. No offense taken.
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