My valve mod.

[styks]

I've been experimenting.
The vavle has had the port angled to around 45deg, removed several threads from the cap and ground out the thread no longer required within the body, valve stem reduced and polished by port, two flats on piercing  probe, external spring. Were valve stem passes through body to hammer I've made a small spring locator and also fitted a nylon sleeve for it to glide in. I had no "C" clips so had to make a spring cap out of a washer, I popped a little resin on the spring side of that washer just up to the first coil to act as a "top hat". If I get the hammer spring just right it shouldn't become coil bound. ... Going by the depth of the hole in the cartridge it should ok, I hope!
Once the resin has cured I'll install and see if there's much reward. ... If it all goes wrong I have a new valve on the way so not much lost except time.

[Gippeto]

Neat!

Have you done any testing with the valve volume/flow mods and an internal spring?

Curious to see what the performance increase is as a result of the small increase in volume.

Al

[chongman]

Sounds cool 

[1377x]

great mods!
i know with the disco valve 20* is the best flow angle according to a guy who did some experiments with the exhaust port angles
let us know how it works out.i like the outside valve spring mod

[styks]

Ok I couldn't resist building it and giving it a try.
Just checked that angle Ed. It's actually 28.5deg, I remember pulling back for fear of
hitting that seat.  I should have asked what the optimum was I guess.

Well did it work, hell yes! I've got an increase in fpe of 15.7% .. It's jumped from 415fps to 480fps, with the same hammer spring
set the same. It's well short of binding the spring so a heavier hammer spring would give me more power and with the p-rod grip frame it would still have a nice trigger. I'm beginning to sound like Jeremy Clarkson, "MORE POWER" 
Lets put it this way, I must fit one of those stock adapters and a stock before it can venture outside.
It was just an experiment, I reckon if I really went to town on one I could push it some more. I love fiddling. 

I'll probably remove though and replace with the new valve keeping this one for another project using the 2250 tube, a lightweight carbine.  I'll then look into bulk fill, internal, don't want a big tank attached.

Damn this forum, I'll be skint before long !!!! 

[1377x]

28.5* is close enough in my book.the guy used a mill to get that 20* angle.i think a drill press and milling vise could get you there also.glad to see your mods are working out.
65fps is impressive for the amount of mods done to just the valve.
what did the mods doto your shot count? less shots no doubt,but by how many?
look close at the CAPOF banner at the top of the screen.notice the "s"-"$"
thats what happens on CAPOF the inside of your pocket will only collect lint because the money that's usually there will be in the guns

[targettgii]

That's funny never noticed that before that's a fact too the lint is going to be lonely.

[styks]

An update. Sorry guys got the fps wrong, I was using my chrony under internal lighting and it was reading wrongly. 
I thought a 65fps increase was "to good to be true" .. Outside today I was getting 465fps not 480fps, still a good increase though.
I have to work on it some more, when the pressure drops in the cart the hammer spring is holding the valve open, I will need to fit a heavier valve spring.
Of course that will drop the velocity some more but at least it won't bleed off half the cart!   
Today my new valve arrived and I did all the same to it bar the external spring mod, it's producing 450fps with a heavier hammer spring.
I'm getting 25 useable shots over 10M before the POI drops too much.

So in answer to Gippeto, I feel the flowing, thread removal etc etc is worth the effort but I don't think the external spring mod is really worth it.
Mind you, I can't say conclusively until I fit a heavier external spring and try it again.

Oh, Ed that p-rod trigger is great, it's really proving itself now I have a heavier hammer spring fitted, the standard trigger was awful with the heavy spring. 

[1377x]

great! im glad the p-rod grip frame is growing on you!
get some more of that valve spring testing done i might have to try it if it works out!
the 415 to 465 is till a good jump in velocity
going by the 450 coming from the stock valve its still another 15fps increase and every increase counts.get another 10 fps increase from adding a long probe another 10 from using a top seal on the transfer port now your up another 35 fps
if you have a pellet scale weigh your carts and only use the ones with the same weight
i have seen the external valve spring mod on other forums and this one iirc quickster did it some time ago.it wont hurt to check out some of those threads if you havent already.try the the green forum and have a look around here

[Jetstream]

Ok I couldn't resist building it and giving it a try.
Just checked that angle Ed. It's actually 28.5deg, I remember pulling back for fear of
hitting that seat.  I should have asked what the optimum was I guess.

Well did it work, hell yes! I've got an increase in fpe of 15.7% .. It's jumped from 415fps to 480fps, with the same hammer spring
set the same. It's well short of binding the spring so a heavier hammer spring would give me more power and with the p-rod grip frame it would still have a nice trigger. I'm beginning to sound like Jeremy Clarkson, "MORE POWER" 
Lets put it this way, I must fit one of those stock adapters and a stock before it can venture outside.
It was just an experiment, I reckon if I really went to town on one I could push it some more. I love fiddling. 

I'll probably remove though and replace with the new valve keeping this one for another project using the 2250 tube, a lightweight carbine.  I'll then look into bulk fill, internal, don't want a big tank attached.

Damn this forum, I'll be skint before long !!!! 

Good job on the valve mate  . Your right about the "Skint" and it gets worse  . ATB, Mark

[styks]

great! im glad the p-rod grip frame is growing on you!
get some more of that valve spring testing done i might have to try it if it works out!
the 415 to 465 is till a good jump in velocity
going by the 450 coming from the stock valve its still another 15fps increase and every increase counts.get another 10 fps increase from adding a long probe another 10 from using a top seal on the transfer port now your up another 35 fps
if you have a pellet scale weigh your carts and only use the ones with the same weight
i have seen the external valve spring mod on other forums and this one iirc quickster did it some time ago.it wont hurt to check out some of those threads if you havent already.try the the green forum and have a look around here

I'll have a good look around for those threads. The longer probe I've not seen yet will look into that.
I have just been reading about the O'Ring buffer mod, I've just done it to my p-rod which arrived today, I love this little carbine, so maneuverable, can't wait to get out in the field with it. Yet to do a proper shot string and play with the settings/adjustment some more, good so far though.
Back to the 2240 hybrid, I've used "gas tight" when refitting the transfer port, had some in my box, it should seal the TP to barrel ok.
I'll weigh those carts, cheers, do they vary that much?

[1377x]

from what i have read the carts can vary enough to make a difference

[styks]

I'll weigh them then for taking velocity readings, I was half asleep last night, the pellet probe of course, I have the longer one from Gmac.