22xx valve mods

[MustangMike]

I'm running a 7.5 with 2 added set screws but it hasn't been test on the carbine yet I think..

But its making a hair more then 40 so if urs is holding up then mine shouldn't have a problem

[alex77147]

I'm running a 7.5 with 2 added set screws but it hasn't been test on the carbine yet I think..

But its making a hair more then 40 so if urs is holding up then mine shouldn't have a problem

yeah i'm sure it will hold, I have 2 set screws total.  I will let you know when it blows up or if it does lol.  I would think it should hold though, doesn't tko make ldc for the more powerful stuff like condors and sumatras?

[MustangMike]

I believe those are full shrouds

[1377x]

the reason i asked is i had a disco pistol with the valve modded per rsternes instruction
it turned out to be a powerhouse and air hog
i had the discovery 6.5 tko after the mods the tko did very little for the noise
ened up making one that made you think you ran out of air the only give away was the sound of the pellet traveling through the air and the impact.the impact noise was very rewarding

[MustangMike]

odds are sooner or later i will end up with a riser block and full shroud

[alex77147]

odds are sooner or later i will end up with a riser block and full shroud

same here, either a miltishot riser breech, or a breach riser with a qb mag, then I will need a full shroud for the barrel.

[lloyd-ss]

the reason i asked is i had a disco pistol with the valve modded per rsternes instruction
it turned out to be a powerhouse and air hog
i had the discovery 6.5 tko after the mods the tko did very little for the noise
ened up making one that made you think you ran out of air the only give away was the sound of the pellet traveling through the air and the impact.the impact noise was very rewarding

Did you make something much bigger than the tko to absorb all that air?

[alex77147]

Another update, before tearing this thing down again I decided to see what velocity I got with jsb 18.1gr pellets.  This test was done with the heavy hammer spring turned to coil bind and filled to the pressure specified then shot.  Also when shooting I felt a very minor puff around the breech where the t port is.

Pressure(psi)  Velocity(feet per second)  Muzzle energy(FPE) 
850               751                                22.6
1350             863                                30
1800             970                                38

After testing I filled it to 1800psi and used a 25.4gr jsb, fired and got 890feet per second or 44.6fpe.  I will retest after the inside of the valve is bored out.

[alex77147]

what is the difference between the valve stem springs in a 2260 valve and a disco valve? is the disco spring thicker?

[rsterne]

The valve spring in a 22XX and a Disco is the same.... I understand some very late model 22XXs have a lighter spring, but I've never seen one....

Bob

[AllanWJ]

what is the difference between the valve stem springs in a 2260 valve and a disco valve? is the disco spring thicker?

I was confused about this too alex. I bought 4 22xx valves over the last month and a half along with 2 plastic-pack 2240's off the shelf and they all had the weaker springs in them (the one on the left). The disco valve I just bought had the spring on the right and when I tried to order 22xx springs from Crosman, they sent me the Disco springs. So if you buy a valve or a 2240 off the shelf, you'll get the springs on the left; if you try and order those same springs individually, you'll get the ones on the right. The parts no's are correct, but they're (quite a bit) different than the ones in the valves and guns.



The one on the left is .032 X .93 and the one on the right is .041 X .78 (wire dias are subject to a 30 year old pair of calipers that have seen alot of use ) Also, my 2400KT also had the weaker spring.

[alex77147]

well i would like to get a weaker spring, If someone has a spare I will paypal for the spring and shipping Or maybe you can get a similar one at harbor freight??

[rsterne]

I would assume the springs Crosman are supplying are from old stock, as they appear to have changed the spring in the 22XX valve relatively recently.... Since the 22XXs came out (decades?) until very recently, they used the same spring as the Disco.... or rather vice-verse, since the Disco came out after the 22XXs....

Bob

[alex77147]

so where can I get a lighter spring?

[lloyd-ss]

Alex,
Given that both springs compress to the same final length, there might not be much difference in the final compressed force of the 2 springs.  Performance wise, you might see almost no difference.
I have run guns with no return spring and gotten only a little more power than with a standard return spring.
Lloyd-ss

[rsterne]

I have run guns with no return spring and gotten only a little more power than with a standard return spring.

and I would guess that getting rid of the restriction caused by the spring is responsible for most if not all of the small increase you noticed....

Alex, consider this.... At 2000 psi, there is a total force of about 130 lbs holding a Disco valve closed.... Only 7 lbs. of that is the spring, all the rest is the air pressure.... Replacing the spring with one with half as much force would reduce the total by less than 3%.... If you increase the preload on the hammer spring by only a fraction of a turn, you can easily compensate for that 3%.... IMO, this is not the place to be looking to increase power, unless you get rid of the spring completely to clean up the flow inside the valve....

Bob

[alex77147]

I have run guns with no return spring and gotten only a little more power than with a standard return spring.

and I would guess that getting rid of the restriction caused by the spring is responsible for most if not all of the small increase you noticed....

Alex, consider this.... At 2000 psi, there is a total force of about 130 lbs holding a Disco valve closed.... Only 7 lbs. of that is the spring, all the rest is the air pressure.... Replacing the spring with one with half as much force would reduce the total by less than 3%.... If you increase the preload on the hammer spring by only a fraction of a turn, you can easily compensate for that 3%.... IMO, this is not the place to be looking to increase power, unless you get rid of the spring completely to clean up the flow inside the valve....

Bob

makes sense, don't know why I didn't think of it

[1377x]

I have run guns with no return spring and gotten only a little more power than with a standard return spring.

and I would guess that getting rid of the restriction caused by the spring is responsible for most if not all of the small increase you noticed....

Alex, consider this.... At 2000 psi, there is a total force of about 130 lbs holding a Disco valve closed.... Only 7 lbs. of that is the spring, all the rest is the air pressure.... Replacing the spring with one with half as much force would reduce the total by less than 3%.... If you increase the preload on the hammer spring by only a fraction of a turn, you can easily compensate for that 3%.... IMO, this is not the place to be looking to increase power, unless you get rid of the spring completely to clean up the flow inside the valve....

Bob

have you done the exterior valve spring mod? if so what were the results

[rsterne]

Nope, haven't done it, don't see the point.... There is very little valve stem, and half that is travel.... I'm not sold on the idea of a C-clip for a retainer....

Bob

[alex77147]

I thought about the exterior spring mod but the c-clip will break from the impact and depending what spring is used the valve stem will have less travel once the spring hits coil bind.