Regulator issues in a Maximus

[KnifeMaker]

Been putting this off for weeks. I did a full .156-7" port job on the valve, transfer and bbl, and added an SSG. Polished hammer tube, adjustable spring guide with the ssg. Marauder Trigger, Gen I. BNM Breech.

Put a new Huma in it, and cannot get a flat string for the life of me!

Called Travis, and followed his instructions in taking it apart and a full cleaning, re-installed, and tested.

Test started at a set pressure in the reg of 2000 psi. also tested at 90 bar. No matter what pressure it is set at, there is NO flat string.

One of the things I was hoping to do after installing better valve screws, was raise the gun pressure to 2300-2400 psi, and shoot down to reg set pressure. However, just like before reg, the numbers fps wise is very low at anything over 1900 psi. Even with the reg set at 90 bar, (1300 psi). Exactly the same type issue as no reg.

I checked the vent hole, thinking that the atmosphere hole was blocked. Well, it was, with a lot of silicone grease. Cleaned everything well, re-assembled, and NO change. It did give a slightly better string though.

Only thing I can think of, is the body of the reg. shows scuff marks from putting it in the tube,and out of the tube. Tells me that it is tight in the tube, so apparently, or I should say, possibly it is too tight in the tube, preventing the bleed air from reaching atmosphere.

the Reg has a .25 peplum, so plenty of air available for decent fps.

At 2000 psi, the fps starts at 770's and climbs to 860's by the time it reaches 1900 psi. Regardless of whether it is set at 2000 psi or 1300 psi.

Any thoughts would be greatly appreciated!

KnifeMaker   

[FuzzyGrub]

You mentioned similar behaviors before and after reg install.  That suggests to me that the reg is not working and full pressure is in plenum.  The Huma reg in Maximus doesn't have a gauge block.  If you haven't, try installing the gauge block to verify the reg set pressure. 
 

[travelbike]

My guess too is regulator is not working.

Is your maximus a .177 or .22 ?  I too have a Euro Maximus .177 which was terribly under powered (650 fps using 8.3gr) with spiking fps.  Oversized the transfer port from stock .05 to .07. Also used the  Challenger hammer spring.  When pumped to 1750 psi shot down to about 1200, it would show curve starting at about  low 700s, peaking close to 800 at about 1400psi and down to mid 700 as we get closer to 1100 psi. 

Instead of using a an internal regulator, used a ninja 13ci tank regulated at 1100 psi.  Plumbed it direct to the fill port to test.  It now shoots at 750 fps with very little spread (no more than 5 fps).  It's still a work in progress. Might add another shim to the tank reg so hopefully raise the pressure to about 1400 psi to hit the magic 12fpe. Might also just tether it to the tank using a coiled line via the gage block, then move gage to fill port.

Keep us updated.  Really interested in what reg pressure you end up with. Good luck.

[Thiel]

i would dissasamble the regulator. there is a revision guide PDF available for download on the huma site.

maybe you can find the issue.

[rsterne]

The vent hole does not need to pass any volume of air, it just needs to be able to "see" atmospheric pressure, so that the regulator knows what the reference pressure is.... and to allow any small amount of air that might leak past an O-ring to escape and not increase the pressure in the Belleville spring chamber.... If the pressure there increases, the regulator setpoint will gradually increase until the reg. stops working completely, and you just end up with tank pressure at the output....

Since the Huma is vented, I assume you either have drilled a vent hole in the tube, or it vents through the gauge port hole in the Maximus?.... The fact that there was some Silicone grease in the vent hole likely means the regulator is NOT leaking, or the air moving through that hole would have blown that grease out of the vent hole.... JMO....

The symptoms you describe do, indeed, seem to indicate the reg. is not working, any you are still seeing the original bell-curve.... although you do not specifically state that....

Bob

[KnifeMaker]

Thanks for the reply Guys!

Bob, it vents thru the gage block hole. Silicone is probably from what is put on the "0" rings for installation.

Seems the actual body of the reg/plenum is large enough in Dia.  to possibly block air or atmosphere from being sampled by the reg. (Too tight in tube).
It is indeed a standard bell curve.

Thinking of milling a channel in the body of the reg and plenum in order to be sure it is in fact seeing the atmosphere.

Knife

[ackuric]

Generally when a regulator isn't vented it will destroy itself in fairly short time, a well designed regulator is repairable once this occurs. My guess is the regulator is no good, either from your findings of the body being too tight of tolerance to the tube, or it arriving DOA at your door.

As others have suggested I would obtain an exploded view/diagram of the reg, and take it apart to see if you can find out whats wrong, short of that I'd just seek a replacement from the manufacturer.

Good luck,
-Matt

[KnifeMaker]

I took it apart a week ago as per

Travis's instructions. Huma drawing did not show what I wanted to know.

Everything looked factory fresh. Could find nothing wrong what so ever other than two of the washers were some what hard to part. The edges were stuck firm. Separated them before re-assembly.

No change.

Will try to contact

Huma directly.

Purchased from Trenier outdoors. They say not to call them for issues. (Talk about customer support)!!!  lol

Knife

[FuzzyGrub]

Seems the actual body of the reg/plenum is large enough in Dia.  to possibly block air or atmosphere from being sampled by the reg. (Too tight in tube).

I don't recall having any fitment issues with the Huma and installing in my maximus tubed prod.  If it was a tight fit, I would have noticed that.   Put the calipers on the OD of the reg and compare to the gauge block.   If the tube was under sized you should have seen similar issues with your valve and gauge block.  Having that info available to give to Huma, may be helpful in getting a replacement.

[KnifeMaker]

Called Trenier today. Turns out, the don't call issue is only for people wanting to be educated on how to tune an AG. Too many different types to make it a timely thing for them.

Discussed the behavior of the HUMA and they were very fast with telling me that it does indeed sound as if there is a problem with the Reg.  They are contacting HUMA directly, and will ship a new reg. to me.

Now THAT's Customer service!!!

Knife

[FuzzyGrub]

Good to hear that.   

[farmerjoe99]

Glad to here it, Jeff at Trenier is an awesome guy and its always a pleasure working with him,
hope you are able to get the regulator fixed/figured out.

[KnifeMaker]

Thanks Guys!!!

Joseph, the Challenger hammer worked miracles!

I use the mill and recessed the hammer face in order to set the striker 60 thousands" in. That small amount of added hammer throw added right at 40 fps with the 14.3's. along with steadier Chrono readings. Apparently the cut out in the standard Disco/Maximus hammer doesn't play well with the MRod Trigger. 

Knife