Semi Auto fail!!

Gun Freak · Fri Aug 12, 2011 9:41 pm

Tell clippard, they'll probably send you a new one.

POLAND_SPUD · Fri Aug 12, 2011 9:52 pm

MVVO-3 Normally Open Poppet valve

Uhmm didn't you mean -> MVJO-3 normally open spool valve ?

At first I thought you meant MJVO-3 but you made a typo... now I am not sure because MJVO-3 is a spool valve

Are you sure it's a normally open valve ? maybe they fu## ## your order

That doesn't explain why the QEV fires when you press the trigger (I understand that's when it happens, right ?), but I guess you can check if your valve works in the right way

blow through P port (inlet) - does it the air come out through port A (outlet)? then press the button and blow air through outlet - it should vent

django · Fri Aug 12, 2011 10:18 pm

The Pilot I have is listed in the heading of my big Clippard Catalog I have as a J- series 3- way Poppet Valve part no MJV0-3 but listed further down as a Normally open Spool Valve?

If I blow through the inlet with the button out the air comes out of the OUT Port , if I press the button while blowing it stops the air coming out of the Out Port.

Do I need a different pilot Valve????, and why does it fire the Qev Fine but not the Cylinder.....it makes no sense?

The Poppet Valve is second hand too I was using it on another gun for a spell and worked fine then,the shop where I buy these is closed today so have to wait until monday to get another valve...

POLAND_SPUD · Fri Aug 12, 2011 10:31 pm

lol now I am lost... it should work

add a pressure gauge between the air cylinder and the QEV... if the pressure drops then the air cylinder is to be blamed

jazzman56 · Fri Aug 12, 2011 10:49 pm

Sorry to sound like an idiot but how does this sort of semi auto work. I've looked at all the diagrams and still haven't the faintest clue of how it works.

How does the qev fire the bb and actuate the cylinder rod???

django · Sat Aug 13, 2011 1:32 am

POLAND :I dont have a Gauge to test Pressure Drop,so even if I buy a new Poppet Valve its not going to fix the situation is it!?.

The Cylinder was brand new and cost over $40.00 Aust!,I just cant see why it wont work,I thought it might be the small size of the Cylinder but regardless it should still function correctly when screwed directly into the Poppet Valve!. The Spring in the Cylinder seems to have enough oomph to retract it too and its single acting so by rights should work!.

JAZZMAN: Have a look at my Aluminium Feeder Block,theres a hole drilled from left to right and a smaller hole coming from the top of the block to feed bbs and a hole on the bottom of the block where the QEV Screws in.

The Air comes into that Brass Poppet Valve passes through one of the Qev's Ports and fills up the threaded brass Air Chamber and Air Cylinder...pushing the Air Cylinder's Rod in an extended position when pressurized. You Depress the Button on the Poppet Valve and it shuts off the air,the Qev now fires and the Cylinder's Rod cycles backwards/Forwards once (extremey fast).

The BBs Drop in from the top of the block and are stopped by the Cylinder's rod,when the Rod retracts one bb drops into the block and is then slammed forwards by the rod then expelled out the barrel by Air from the Qev Firing.....

EDIT: Just had another look at this thing and I have a theory,That little Brass Conical fitting I use that screws into the back of the Cylinder is an 1/4" to 5mm Airbrush Fitting,the threaded hole in the rear of cylinder is only 5mm in Dia. Now in that Brass Fitting the hole size is reduced down to about 1.5mm and no I cant widen the hole cause the top of the fitting is very,very small/weak as it is.

This is what I used guys http://www.myshopping.com.au/ZM--700466 ... d_Hardware

Would this airhole reduction be the cause?

POLAND_SPUD · Sat Aug 13, 2011 4:16 am

Would this airhole reduction be the cause?

possibly... does the air cylinder retracts if you keep the button pressed ?

django · Sat Aug 13, 2011 4:53 am

POLAND_SPUD wrote:
Would this airhole reduction be the cause?
possibly... does the air cylinder retracts if you keep the button pressed ?

NO it doesnt,it wont if you keep your finger on the button but when you let go of the button it then retracts and not really quickly as it's supose to either????. I'll have to take it to the shop where I bought it all from next week and ask them but I dont like doing that as they allways ask the dreaded question" what are you making with all this?".

so I'll have to make up a story as a lot of folk get all bent outa shape here if you say your making a BB Gun! due to Aussie Gun Laws

.....

POLAND_SPUD · Sat Aug 13, 2011 5:02 am

I must say I find this thread depressing... I've never had any problems with QEV + 3 way + air cylinder combo

I am totally lost... I have no idea WTF is wrong..... FAIL

django · Sat Aug 13, 2011 5:15 am

Im not happy,I REALLY wanted this to work and wasted a lot of money on parts for it,you guys seem to have had no probs making similar guns with the same parts yet I make one and it doesnt work!!?.

It can only be a problem with the 3 way or Cylinder,im thinking somehow the cylinder is unsuitable in some way I don't know of!? but I do thank eveyone who has tried to help

.

Gun Freak · Sat Aug 13, 2011 8:49 am

Take it to the place and demand a refund or replacement.

django · Sat Aug 13, 2011 9:33 am

Gun Freak wrote:Take it to the place and demand a refund or replacement.

Im going to where I bought the Cylinder next week and see what they suggest?,I bought it some time ago and sure there will be no refund but I'll get it work somehow!?.

I think that Tiny hole in the brass adaptor to the Cylinder is the cause and is so small the cylinder is not reading the pressure drop so not actuating correctly??.

Mr.Tallahassee · Sat Aug 13, 2011 10:26 am

That little hose adapter HAS to be the problem. I bet that the flow through it is so slow that when you pilot the system it dumps the pressure from the QEV but the pressure in the air cylinder is sufficient to keep it extended. Only true test is opening the port size but I don't know if you could actually do that. You COULD make your own air cylinder and use larger porting on it. It shouldn't be difficult at all.

Gun Freak · Sat Aug 13, 2011 11:35 am

If a 10-32 hole is too small for the cylinder to retract then I don't think clippard would have designed it. There is plenty of room for the cylinder to exhaust, especially because it is so tiny.

django · Sat Aug 13, 2011 1:14 pm

Yes BUT the hole in that Brass Adaptor screwed into the rear of the Air Cylinder is only 1mm or so wide,its made for Airbrush's.

I think Mr Tallahessee and my theory is the cause!?,although the Air Cylinders rear port is 5mm its now restricted down to 1mm because of the brass adaptor. Surely the only logical explanation?