Liberty Reg not working

[Madd Hatter]

Just did a 40 shot shot string.

Created   Description   Notes1   Notes2   Distance   Coeff   Weight   Temp   BP
7/10/2019 14:19   lowered reg pressure         2   0.023   14.3   88 °F   1018.00 inHG
#   FPS   FT-LBS   PF               
43   989   31.06   14.14               
42   1005   32.08   14.37               
41   1024   33.3   14.64               
40   1027   33.5   14.69               
39   1043   34.55   14.91               
38   1057   35.48   15.12               
37   1061   35.75   15.17               
36   1074   36.63   15.36               
35   1087   37.52   15.54               
34   1082   37.18   15.47               
33   1087   37.52   15.54               
32   1085   37.39   15.52               
31   1080   37.04   15.44               
30   1062   35.82   15.19               
29   1050   35.01   15.02               
28   1030   33.69   14.73               
27   1009   32.33   14.43               
26   982   30.62   14.04               
25   966   29.64   13.81               
24   ERROR 3                     
23   925   27.17   13.23               
22   914   26.53   13.07               
21   899   25.67   12.86               
20   862   23.6   12.33               
19   854   23.16   12.21               
18   858   23.38   12.27               
17   839   22.36   12               
16   823   21.51   11.77               
15   797   20.17   11.4               
14   775   19.07   11.08               
13   770   18.83   11.01               
12   767   18.68   10.97               
11   763   18.49   10.91               
10   743   17.53   10.62               
9   735   17.16   10.51               
8   ERROR 3                     
7   ERROR 3                     
6   708   15.92   10.12               
5   709   15.96   10.14               
4   703   15.7   10.05               
3   709   15.96   10.14               
2   704   15.74   10.07               
1   697   15.43   9.97               
AVG   StdDev   Min   Max   Spread   TrueMV   Shots/Sec   Group Size   
908.85   141.64   697   1087   390   917.86   0.04   0

Only 2 things have been changed, the valve which I know works and the bellevue washers. Either the spring Duy sent didn't get put in place to push the reg closed or the washers are the problem. Going to take the rifle apart and check things out plus remove the extra washer I put behind the hammer spring as once the pressure gets down to around 2000 psi or below all of the pressure just leaks out. I think the stock washers are going back in and we'll see how that works. The above string was with the reg turned 1/4 turn clockwise so the begining vel, were expected but then it hit the sweet spot around 2900 psi and holy moly thought for sure it was going to crack the sound barrier.   

[Madd Hatter]

I think I need a stiffer valve spring. I don't think it's putting enough pressure on the reg and I had a heck of a time getting the poppet valve to seal so I could pump it up by hand even with the hammer spring out. May have to reinstall the stock valve and call it good. I removed all of the shims except 1 and I had to leave that 1 in to keep the spring from chewing up the spring holder(?) that's made out of plastic. Yeah I could've used my compressor but wanted to make sure I could pump it up with a floor pump. I did install the original washers so we'll see in the morning what's what.

[FuzzyGrub]

Light valve springs can be "fun" to get sealed, especially in a reg'ed gun.  With non-reg, you can hit it with a small burst of air to seal it.  On reg guns, I've "cooked" some regulator O-rings doing that.   

[nervoustrigger]

Yes it looks like the regulator is being bypassed and it’s operating like an unregulated PCP with a bell curve.  Possible causes:
 
1.       Bellevilles are configured in a manner that is too stiff, and the stack cannot compress adequately for the regulator spool to move and seal off against the valve seat.
2.       Belleville stack is simply too tall and it is getting squished flat on assembly.
3.       If the regulator has an adjustable seat, it may be adjusted out so far that the spool can never reach it.
4.       The valve seat or the end of the piston is damaged and it can’t seal off when the two parts meet.
 
Since you had changed the washers, my guess is the two most likely causes are #1 or #2.
 
BTW, I don’t follow what you mean with “I don’t think [the valve spring] is putting enough pressure on the reg”.  The reg does not need pressure applied from the valve spring, does it?  Or do you mean the spring isn’t strong enough and that’s why the poppet won’t seal?  The latter makes more sense but please note that even a very stiff valve spring is completely dwarfed by the air pressure pushing against the poppet.  For example a very strong valve spring might be holding the poppet closed with 10lbs of force.  If the poppet is 0.3” diameter, it has another 140lbs of force holding it closed when the plenum is at 2000psi.  Just trying to put that into perspective…a stronger spring will not fix the poppet sealing issue.  Look instead at how well the poppet and valve seat mate to each other.  Burnish them together with a light abrasive.  If you color the surfaces with a marker, you will quickly expose the high spots and low spots and you can follow your progress as you lap them together.

[darkcharisma]

the valve is holding air 100%, i tested this valve 3 days and nights and it was holding air absolute. the Valve stem is sooooo long that when you get to 2000psi. the hammer is of course constantly resting on the stem after each shot...it is pushing the valve open. cock it back and fill to higher pressures. it is working as it should which is pushing heavy pellets.

for low power setting. my suggestion is to lower the reg to stock setting or around 2200psi or just above the pressure which the hammer cannot open after the shot.

for higher power. set the reg to 2900psi. this valve is easier to open as is. it will be easier to open if added hammer weight.

yeah someone tell me more about the valve spring pushing the reg face back. i didn't think the valve spring was designed to do that. it is my understanding that the pressure inside the chamber between valve and reg will push the reg stem and seal it against the brass wheel end.

[FuzzyGrub]

yeah someone tell me more about the valve spring pushing the reg face back. i didn't think the valve spring was designed to do that.

I don't think so either.  It is just holding the other side of the poppet spring. 




When I've gone to a lighter valve spring, it was in conjunction with a much lighter hammer and operating at a reduced pressure, for more efficiency.   In my case, was just going from a oem crosman valve spring to a lighter conical spring.  Burnishing and spinning the poppet helped, but getting the initial seal was still problematic.  Once it had 1kpsi, no issues. 

My guess is that the lighter valve spring in this case, is trying to get more power with a longer dwell.  While the oem Liberty has zero hammer pre-load, adding enough washers will produce some pre-load, which at some pressure, will keep the poppet open.  If you need the pre-load, might try the oem valve spring before going back to oem valve.  That is, if it is compatible with the aftermarket valve.

[Madd Hatter]

the valve is holding air 100%, i tested this valve 3 days and nights and it was holding air absolute. the Valve stem is sooooo long that when you get to 2000psi. the hammer is of course constantly resting on the stem after each shot...it is pushing the valve open. cock it back and fill to higher pressures. it is working as it should which is pushing heavy pellets.

for low power setting. my suggestion is to lower the reg to stock setting or around 2200psi or just above the pressure which the hammer cannot open after the shot.

for higher power. set the reg to 2900psi. this valve is easier to open as is. it will be easier to open if added hammer weight.

yeah someone tell me more about the valve spring pushing the reg face back. i didn't think the valve spring was designed to do that. it is my understanding that the pressure inside the chamber between valve and reg will push the reg stem and seal it against the brass wheel end.

I tried it today without the shims on the hammer spring and as expected the velocity never got above 600 fps. I think the problem I'm having is the long stem. Even with all of the shims but 1 there's still pressure against the hammer spring. It did seal and hold pressure and I think it was my fault it didn't seal before. I took it back apart and turned the poppet back and forth a few times and it sealed even using the floor pump. I have the reg adj to original with the original stack patern. Disregard my previous post. When I posted it I was cooked from being in the garage for around 3 hrs and the temperature was between 95 and 100. Then it didn't help matters when hand pumping from 0 up to just under 2000 psi. Needless to say I was dripping wet when I came in.

Duy, the main reason I wanted your valve is the original is going to fail not for the increase in power. I do like the potential of more power but my main concern was reliability.

[darkcharisma]

Robert, the stem can be shortened to oem length by cutting with either diamond files or cutting wheel then grind to proper length.

  the valves throat is .255 and exhaust is .217. so if you cut the stem shorter, you will still get more power compared to OEM.

since i mainly make valves for power i went for maximum dwell, but cutting them short will become "turning" process and is up to end user, unless you want me to do it.

i see a trend of low fps with high fills at 4000psi. try filling to only 3500psi and shoot to 2500psi.

[Madd Hatter]

Robert, the stem can be shortened to oem length by cutting with either diamond files or cutting wheel then grind to proper length.

  the valves throat is .255 and exhaust is .217. so if you cut the stem shorter, you will still get more power compared to OEM.

since i mainly make valves for power i went for maximum dwell, but cutting them short will become "turning" process and is up to end user, unless you want me to do it.

i see a trend of low fps with high fills at 4000psi. try filling to only 3500psi and shoot to 2500psi.

That's pretty much what I was figuring I'll have to do then add a bunch of shims. I won't be doing much with it for awhile as it's just to darn hot and my old body can't tolerate it anymore. When I first moved here 15 years ago I was out in the front yard digging a sprinkler trench in 110F heat and it didn't bother me but now....... 

[Madd Hatter]

Duy, how much longer is the stem from stock length?

[darkcharisma]

its almost double in length from back of valve to the end of stem. 

it doesn't need to be precise. dremel and cutting wheel my friend.

[Madd Hatter]

Thanks

[wll2506]

Robert, the stem can be shortened to oem length by cutting with either diamond files or cutting wheel then grind to proper length.

  the valves throat is .255 and exhaust is .217. so if you cut the stem shorter, you will still get more power compared to OEM.

since i mainly make valves for power i went for maximum dwell, but cutting them short will become "turning" process and is up to end user, unless you want me to do it.

i see a trend of low fps with high fills at 4000psi. try filling to only 3500psi and shoot to 2500psi.

That's pretty much what I was figuring I'll have to do then add a bunch of shims. I won't be doing much with it for awhile as it's just to darn hot and my old body can't tolerate it anymore. When I first moved here 15 years ago I was out in the front yard digging a sprinkler trench in 110F heat and it didn't bother me but now.......

My general manager who is about 40 years younger than I am just about passed out today because of the heat,

I went out from one office to another and felt sick as heck.... this heat is no joke !!!!

wll

[darkcharisma]

i don't get it Robert. who would pass out during 75-77 degrees heat? only the ones that has COPD. in texas we are dealing with 87-93 degrees. and i kayak on a 90 degree the other day.  i went from orange to black cow skine to e just like that. 

[wll2506]

i don't get it Robert. who would pass out during 75-77 degrees heat? only the ones that has COPD. in texas we are dealing with 87-93 degrees. and i kayak on a 90 degree the other day.  i went from orange to black cow skine to e just like that. 

Usually not but today was very strange ... folks were freaking out at the heat and it was 105 today ... usually this time of year it is 110-115.... I came out from work and the sun/heat hit me like a freight train ... Wow !!!

wll

[Madd Hatter]

i don't get it Robert. who would pass out during 75-77 degrees heat? only the ones that has COPD. in texas we are dealing with 87-93 degrees. and i kayak on a 90 degree the other day.  i went from orange to black cow skine to e just like that. 

I wish only 75-77! lol It was still in the 90's at 10pm last night and we'll be seeing the same temps today and tomorrow plus the day after. Then we get a cold front moving in and it'll be down in the 90's. lol

i don't get it Robert. who would pass out during 75-77 degrees heat? only the ones that has COPD. in texas we are dealing with 87-93 degrees. and i kayak on a 90 degree the other day.  i went from orange to black cow skine to e just like that. 

Usually not but today was very strange ... folks were freaking out at the heat and it was 105 today ... usually this time of year it is 110-115.... I came out from work and the sun/heat hit me like a freight train ... Wow !!!

wll

Yeah, it is strange, it feels so much hotter but really isn't. My wife who normally is the one who loves the heat has been complaining about how hot it is. Of course she's in the house most of the time and doesn't venture out until almost sunset. Just 2 or 3 years ago we were getting 112f everyday for weeks at a time and if it dropped out of the 90's at night I didn't notice.

[wll2506]

Robert,

Did you get your regulator to start to work , I hope so !

I gave mine a twist (1/8-1/4 turn) counter clockwise when I first got the gun, but I have an idea my regulator is still set around 1900 to 2000 psi range, but with mine I have a good hunch it is my hammer spring.

I'm getting to that *(&^ or high water tomorrow !!!

wll

[Madd Hatter]

Not yet. Spent most of yesterday up on the roof trying to find a little tick that is driving my wife crazy (a very short drive!). Today I'm making a mister string for the back yard to try and cool it of a little for the dogs and me seeings how I seem to be in the dog house ALL of the time! lol

[Madd Hatter]

Well, I did get to do about 4 or 5 hours work on the Liberty. I had a very hard time getting the hammer out. Not the part of taking parts off to access it but actually getting it out of the receiver. Finally got it out after much much much cussing and .....   Can't figure out what the heck is the problem. When it gets back to where the sear engages the hammer it gets real tight. I've polished the heck out of the hammer and it looks pretty but is still not sliding freely in the last 1/16 inch. I took Duy's valve out and burnished with some polishing compound. Even pulled out the bolt and polished it up to make it cock real slick. Need to get some 3/8 alu dowel so I can chuck the hammer up in my drill press and do some more polishing and maybe get the hammer to move real smooth. Have no idea why it's giving me so many problems except it's be real hot in the garage and maybe the alu receiver has expanded. Naw, that would make it looser. ? I took the reg apart again and double checked the washer stack to make sure it's stock. Cleaned out the vent hole to make sure pressure wasn't building up where the washers are. The stack is )))((()))((()))((()))(((. Each stack of 3 measured .072 to .073 thick. Checked where the reg stem seals against the nylon in the reg adj body and both are smooth. Almost to the point of putting the original valve back in and install a .100 HS shim stack and call it quits.

Would be real nice if I had a gauge on the reservoir to know what the heck the reg was doing. Without one it's just guess work.

[cosmic]

The trigger assembly is removed correct..  Look underneath for a hex and remove it .. I'm just guessing.. Maybe the hammer spring got hung up on the guide and messed that part of the receiver up...