There is no such thing as a pilot valve that's too big If you open your ball valve fast enough it should work even at lower pressures.Alster370 wrote:I think this is because my pilot is a 15mm ball valve and that its too big?
First Airgun
- jackssmirkingrevenge
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Most QEVs have cup pistons that effectively act as one-way valves, allowing air to flow from the pilot to the chamber but not vice versa.
This means that the air that can flow out of the pilot cannot flow out of the barrel.
This means that the air that can flow out of the pilot cannot flow out of the barrel.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Photo?Alster370 wrote:From visual inspection mine seems to be just a flat face piston, not a cup one.
It could be a diaphragm with a equalisation hole, like in a piston valve.
hectmarr wrote:You have to make many weapons, because this field is long and short life
sure, but I can only take one from the barrel side as the pilot side is epoxied already.
I could give you the site I bought it off in the meantime if that helps
http://www.hosefit.co.uk/catalog/produc ... cts_id=357
I could give you the site I bought it off in the meantime if that helps
http://www.hosefit.co.uk/catalog/produc ... cts_id=357
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That should look like the diagram I posted earlier, have you ever taken it apart?
hectmarr wrote:You have to make many weapons, because this field is long and short life
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A good test would have been to plug the chamber end and blow through the barrel end to see if air comes out of the pilot end, is this possible?
hectmarr wrote:You have to make many weapons, because this field is long and short life
yeah I could give that a try, ive got the chamber epoxied shut. Il will do it in an hour or so as my fittings have been redone with epoxy and are drying.
So if I blow into it and no air comes out the pilot , do I have a cup piston after all?
So if I blow into it and no air comes out the pilot , do I have a cup piston after all?
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Technically yes, though what might happen if tolerances are not too good is that your breath alone will not provide sufficient pressure for the cup to seal against the sides of the valve body.Alster370 wrote:So if I blow into it and no air comes out the pilot , do I have a cup piston after all?
hectmarr wrote:You have to make many weapons, because this field is long and short life
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jackssmirkingrevenge wrote:Technically yes, though what might happen if tolerances are not too good is that your breath alone will not provide sufficient pressure for the cup to seal against the sides of the valve body.Alster370 wrote:So if I blow into it and no air comes out the pilot , do I have a cup piston after all?
thats exactly what happens with my qevs.
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no air came out of the pilot at all when I tested it. I have a new problem though, when pressurising I get a tiny bit of air leaking from the qev down the barrel. This is rather annoying because it just pushes the ammo out of the barrel before ive pressurised it fully. I think its because the 1/2 to 15mm fitting is not sealing at the bottom of the threads. would an o ring fix this?
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umm no fittings on the out side should make the qev leak, id say you have a bit of dirt on the piston or seat.
'' To alcohol... The cause of, and solution to, all of life's problems.”
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Add me on ps3: wannafuk, 8/11/11 cant wait
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Well its been a productive last week and the gun is nearly finished (mechanically) just one tiny leak to get rid of and then I can clean it up and move onto the stock. I managed to get the qev to seal at 6psi which is pretty good and stop the air leaking past it.
Not bad to say that a fridge freezer is my workbench and I have to use an adjustable spanner that doesn't lock in place properly
Let me know what you think so far
Not bad to say that a fridge freezer is my workbench and I have to use an adjustable spanner that doesn't lock in place properly
Let me know what you think so far