p15 testing with and without valve return spring

[mackeral5]

I ran a few strings with the P15 this afternoon.  First I ran one with the valve return spring--75 shots of JSB 18.13 averaging 858fps for 29.6fpe.  Then I degassed and removed the valve return spring. Reassembled without making any other adjustments. 

The gun was much louder, I could tell it was wasting a lot of air.  48 shots averaging 883.  31.5fpe.  I think excessive preload was bouncing the hammer off the valve. 

I pulled my SSG and after testing various preloads I ended up setting it at the minimum preload possible.  This still resulted in having a gap setting of approximately .120, far larger than I would typically run with an SSG.  Even at this setting I couldn't dial velocity down as low as my first string. 

This string was more quiet and resulted in 74 shots averaging 869fps/30.4fpe.   



These results do look promising.  However I can't say for certain what is actually causing this. 

Is it the fact that the valve is harder to open with the fairly strong valve return spring??

Is it due to the valve spring restricting airflow when compressed?  I tend to think this is the case.  I will post some pictures later illustrating why.  The spring is relatively large wire diameter, with a lot of coils, and under significant preload when installed.  There's not much room between coils for air to pass. 

I don't want to deal with issues associated with no valve return spring, so i intend on buying/making a very light spring that is more of a poppet retainer than anything else. 

[Rallyshark]

Yes, I need pictures!  I don't know the the valves in the p15, so pictures will help me get it a lot better than a parts diagram for sure.

[Motorhead]

If the P15 is a regulated gun .... some testing of set point pressure could very likely reduce the ES values your seeing.

[mackeral5]

If the P15 is a regulated gun .... some testing of set point pressure could very likely reduce the ES values your seeing.

Understood on the ES, I need to turn the reg down just a little.  Max velocity at this reg setting is a little over 900.  The best ES I've seen with the OEM regulator is around 20 and that was at a higher preload/fpe setting.

[mackeral5]

here are some pics.

valve body, oem poppet, a reduced stem peek poppet, and the oem poppet return spring



Looking into the plenum, with the oem spring inside



The oem valve spring compresses to approximately .80" when installed. 



Here is a light spring I found to replace the oem spring with.  I have to close the coils a bit to reduce OD, but it should work.

[Motorhead]

Likely able to reduce hammer weight too, and/or do some version of an SSG and get the valve dwell really under your control.

[Rallyshark]

Valve spring aside, I think making that PEEK poppet a bit larger in diameter(like the factory poppet), and squaring off the the sealing edge of the poppet is the way to go.  That will make it close faster, while still making it relatively easy to crack the valve.  But yeah, that valve spring is HUGE too! 

[mackeral5]

After seeing how much preload could be reduced after replacing the valve spring I am willing to up-size the poppet. 

I was translating the OEM valve being hard to open due to excessive OD, but  it appears that was due to an  excessive valve spring. 

Some time soon I'll make another poppet.  For now she has a 70+ shot 30fpe tune..

[MB]

Thanks for these threads Mike, I am following with great interest and am taking notes along the way...Please let us know the results and size of the new Valve Spring

[Hobbyman2007]

Holy smokes , that valve spring looks like the hammer spring in my disco . Lol . Your tune doesn’t sound to be too bad as is . I’d really be looking at an SSG or even a short stiff spring to gain efficiency . Or once again a cobra spring system . I’m sure if you have the ability to make a peek poppet and have it seal you could make the cobra system . Can you take a few more pics of the valve ( complete if possible ) I’d like to see what the air inlet looks like .

[mackeral5]

It is equipped with an SSG.   There isn't much room in the p15 and you are pretty much limited to 5/16 OD or smaller springs.  The oem spring has .048 wire, basically the same spring that is in a QB78. I haven't had much luck finding a heavier spring with .330 or less OD and at least .215 id to fit the spring guide.

Note the OEM hammer is just under 20grams.  My hammer is just over 16 grams as I removed 2mm off the face to increase hammer throw.  A little more was removed by drilling the spring hole deeper to allow room for my SSG's spring guide. 

Next time I have the gun apart I will take some pics of the valve area-- there's not much to see.  The silver valve carrier is recessed into the monoblock style breech assembly, then the plenum screws in to the monoblock. the threaded section of the plenum butts up against the valve carrier and the spring fits onto the poppet.  You can see where the black anodize is wearing off from the plenum butting up against the valve carrier. 

I've put the gun back stock and that results in 55-60 shots around 28fpe.  I've read where Swish is getting 80 shots upwards of 30fpe out of a stock P15 with nothing but a preload adjustment.  those are outstanding results, I have a hard time getting my head around them.....

[swish]

It is equipped with an SSG.   There isn't much room in the p15 and you are pretty much limited to 5/16 OD or smaller springs.  The oem spring has .048 wire, basically the same spring that is in a QB78. I haven't had much luck finding a heavier spring with .330 or less OD and at least .215 id to fit the spring guide.

Note the OEM hammer is just under 20grams.  My hammer is just over 16 grams as I removed 2mm off the face to increase hammer throw.  A little more was removed by drilling the spring hole deeper to allow room for my SSG's spring guide. 

Next time I have the gun apart I will take some pics of the valve area-- there's not much to see.  The silver valve carrier is recessed into the monoblock style breech assembly, then the plenum screws in to the monoblock. the threaded section of the plenum butts up against the valve carrier and the spring fits onto the poppet.  You can see where the black anodize is wearing off from the plenum butting up against the valve carrier. 

I've put the gun back stock and that results in 55-60 shots around 28fpe.  I've read where Swish is getting 80 shots upwards of 30fpe out of a stock P15 with nothing but a preload adjustment.  those are outstanding results, I have a hard time getting my head around them.....

Sorry I posted what I was getting but not how I got there.
I polished pretty much every moving part, including the springs. I also flat ground and polished the end of the springs and added a thin nylon washer or two to keep friction to a minimum.
I also ground the corner of the valve transfer port kinda like they do on 2240 valves for better flow. And if I remember correctly I opened up the barrel port a little as well.
The only other thing that is probably helping efficiency is i added a bstaley style oring. I apologize for not keeping better records but I did have to add a little hammer tension after the oring install so I'm pretty sure it's helping. After that I did the 80 shot string.
Counting a little reg creep at first and even few dry fires still a solid 75-80 shots. I love my Ping15! Lol.

[MB]

Hi Chad,

Where did you add the Bstaley Oring?

[mackeral5]

It is equipped with an SSG.   There isn't much room in the p15 and you are pretty much limited to 5/16 OD or smaller springs.  The oem spring has .048 wire, basically the same spring that is in a QB78. I haven't had much luck finding a heavier spring with .330 or less OD and at least .215 id to fit the spring guide.

Note the OEM hammer is just under 20grams.  My hammer is just over 16 grams as I removed 2mm off the face to increase hammer throw.  A little more was removed by drilling the spring hole deeper to allow room for my SSG's spring guide. 

Next time I have the gun apart I will take some pics of the valve area-- there's not much to see.  The silver valve carrier is recessed into the monoblock style breech assembly, then the plenum screws in to the monoblock. the threaded section of the plenum butts up against the valve carrier and the spring fits onto the poppet.  You can see where the black anodize is wearing off from the plenum butting up against the valve carrier. 

I've put the gun back stock and that results in 55-60 shots around 28fpe.  I've read where Swish is getting 80 shots upwards of 30fpe out of a stock P15 with nothing but a preload adjustment.  those are outstanding results, I have a hard time getting my head around them.....

Sorry I posted what I was getting but not how I got there.
I polished pretty much every moving part, including the springs. I also flat ground and polished the end of the springs and added a thin nylon washer or two to keep friction to a minimum.
I also ground the corner of the valve transfer port kinda like they do on 2240 valves for better flow. And if I remember correctly I opened up the barrel port a little as well.
The only other thing that is probably helping efficiency is i added a bstaley style oring. I apologize for not keeping better records but I did have to add a little hammer tension after the oring install so I'm pretty sure it's helping. After that I did the 80 shot string.
Counting a little reg creep at first and even few dry fires still a solid 75-80 shots. I love my Ping15! Lol.

Chad thanks for sharing.  We are very similar regarding mods.  There is something I am missing.  I need to check basics such as probe depth, barrel port alignment, etc.  something just seems to be off.....

Also, I finally got my head around the whole Cobra concept, thanks to Hobbyman's example with his Rainstorm.  I'm pretty sure I can pull it off, but I'm not sure if it will be the P15, R3M, or one of my QB's.  I really want to try it on the Edgun, but the p15 has my attention right now.  The p15 will be the most challenging as it has the smallest space to work.  The Edgun will be the easiest due to its cavernous valve body.....

[swish]

Hi Chad,

Where did you add the Bstaley Oring?

The Bstaley mod is when you add 1 or more orings between the hammer and the valve. Usually they stack against the face of the valve to cushion and rebound the valve closed faster. Or not open the valve farther/longer than need be.

[swish]

It is equipped with an SSG.   There isn't much room in the p15 and you are pretty much limited to 5/16 OD or smaller springs.  The oem spring has .048 wire, basically the same spring that is in a QB78. I haven't had much luck finding a heavier spring with .330 or less OD and at least .215 id to fit the spring guide.

Note the OEM hammer is just under 20grams.  My hammer is just over 16 grams as I removed 2mm off the face to increase hammer throw.  A little more was removed by drilling the spring hole deeper to allow room for my SSG's spring guide. 

Next time I have the gun apart I will take some pics of the valve area-- there's not much to see.  The silver valve carrier is recessed into the monoblock style breech assembly, then the plenum screws in to the monoblock. the threaded section of the plenum butts up against the valve carrier and the spring fits onto the poppet.  You can see where the black anodize is wearing off from the plenum butting up against the valve carrier. 

I've put the gun back stock and that results in 55-60 shots around 28fpe.  I've read where Swish is getting 80 shots upwards of 30fpe out of a stock P15 with nothing but a preload adjustment.  those are outstanding results, I have a hard time getting my head around them.....

Sorry I posted what I was getting but not how I got there.
I polished pretty much every moving part, including the springs. I also flat ground and polished the end of the springs and added a thin nylon washer or two to keep friction to a minimum.
I also ground the corner of the valve transfer port kinda like they do on 2240 valves for better flow. And if I remember correctly I opened up the barrel port a little as well.
The only other thing that is probably helping efficiency is i added a bstaley style oring. I apologize for not keeping better records but I did have to add a little hammer tension after the oring install so I'm pretty sure it's helping. After that I did the 80 shot string.
Counting a little reg creep at first and even few dry fires still a solid 75-80 shots. I love my Ping15! Lol.

Chad thanks for sharing.  We are very similar regarding mods.  There is something I am missing.  I need to check basics such as probe depth, barrel port alignment, etc.  something just seems to be off.....

Also, I finally got my head around the whole Cobra concept, thanks to Hobbyman's example with his Rainstorm.  I'm pretty sure I can pull it off, but I'm not sure if it will be the P15, R3M, or one of my QB's.  I really want to try it on the Edgun, but the p15 has my attention right now.  The p15 will be the most challenging as it has the smallest space to work.  The Edgun will be the easiest due to its cavernous valve body.....

My reg is set right close to 120 bar if that helps any. It was closer to 140 out of the box.

[mackeral5]

Thanks again.  My reg is currently in the 120-125bar range, its hard to be precise.  This regulator has not been rebuilt with fresh orings and polished bellvilles like the one I have attached to the plenum extension....

I checked pellet seating depth by seating a pellet then removing the barrel, wouldn't you know--when seated, you can see the pellet skirt in the edge of the barrel port.  When pushing the pellet beyond the barrel port you feel a distinct hump/resistance, then it breaks free.

At this time I haven't determined what exactly to do to resolve--i have a spare probe, etc so there are options.  I ran out of time tonight.   

I reassembled and ran several 15 shot strings to see how this affected performance.  Some in the middle of the pressure range and some at the top of a full fill.  There were 2 versions of strings.  The first version was seating pellets only with the bolt, waiting 30 seconds, then firing. 

These averaged 870FPS with ES of 20

The next strings I seated pellets with the bolt, then used an allen wrench to seat the pellets another .080" or so.  I could feel the initial resistance of the skirt being in the barrel port then break free as the pellet moved beyond the barrel port. 

These averaged 879 with an ES of 15. 

Its not the largest sample, but there were at least 45 shots of each version fired and both versions had 1 group of 15 from a 3500psi fill. 

In comparing 2 bolt probes  I wasn't lucky enough to find one longer than the other....so it's not going to be as simple as swapping bolts.  I do plan to fully disassemble and verify barrel port to transfer port alignment before making any changes. 

More to follow. 

[MB]

Hi Chad,

Where did you add the Bstaley Oring?

The Bstaley mod is when you add 1 or more orings between the hammer and the valve. Usually they stack against the face of the valve to cushion and rebound the valve closed faster. Or not open the valve farther/longer than need be.

Thanks Chad

[mackeral5]

This evening I pulled the valve body then reassembled the tube, monoblock, and barrel assemblies together.  Essentially mocked it up without any internals.  though I cannot see that far into the transfer port, i was able to use a small allen wrench to feel for a smooth transition from transfer  port to barrel port.  I cannot feel the transition between the two ports except towards the butt.  There is a distinct mismatch in the rear of the ports--call it the rear 1/4.   

The breech end of the barrel is flush with the monoblock and the step down machined into the barrel is flush against the front of the monoblock.  So the barrel is fully seated.  It appears barrel port and monoblock transfer port are slightly out of tolerance, with the barrel port located a little forward of the transfer port in the monoblock.  The amount appears to match the amount of pellet skirt exposed in the barrel port when testing pellet seating depth. 

Now I just have to figure out the best way of resolving.  I see a few options:  1) plug the port, spin the barrel and drill a new transfer port.  2) machine the barrel to move it rearward and then take a little off the breech end of the barrel to keep it flush with the monoblock.  3) enlarge the rear of the barrel port to match the transfer port and make a longer probe.....

I think option 1 may be the best solution???

[Rallyshark]

I vote option 2.  Also, doing option 2, would also effectively move the probe farther into the barrel.  Something about plugging the barrel and getting that right seems more complicated, and prone to a possible failure?  Option 3, seems like more work and opening the barrel port more could cause loading failures?