my qb been modded.
my qb been modded.
I'm guessing those mods are the source of your problem.... Why don't you completely disassemble it, photograph everything, and post the photos here.... It's pretty tough to try and diagnose problems with a stock gun on the internet.... let alone a modded one.... I for one feel like I've wasted my time trying to help because of insufficient information.... People here have been really trying hard to help you.... and NOW we find out the valve stem is not stock?.... C'mon....
Did you do the mods?.... if not, why didn't you go back to the guy who did?....
Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal: Too many to count!
IMG_4649.jpg
hope this pic works
Well it's definitely NOT a stock QB valve stem.... Is the stem loose in the plastic head by any chance?.... Have you checked the overall length of the stem compared to a stock one?....
If you're not running this gun on HPA there is NO reason for changing the valve head.... I suggest you get a stock one, mod it to accept the valve spring, and try that.... While you are at it, get a stock valve spring just in case yours isn't even close to stock....
I'm still betting you have a hammer or sear problem.... Whoever modded the gun could have changed stuff causing your problems....
Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal: Too many to count!
Clear pictures would go a long ways towards deriving an accurate solution to this problem.
Have a camera?
Edit....shoulda noticed the last page....my bad.
I agree with whats been said so far. Clearly the whole valve has been modded so my advice (having just had the royal run around by the same problem) is buy a whole valve. Also compare your hammer to the picture Dukemeister posted. If they don't look the same buy a hammer too.
Don't worry about losing anything performance wise. There is little to be gained by doing those particular valve mods running CO2 or moderate HPA. In fact with CO2 there is nothing to be gained.
Changing the transfer port seal will give you 99% of everything there is to be had on CO2
Sean
How did you make out with things? If you are close to Ottawa I could give you a hand with it. I have done some modifications to my sons qb (he is only alow to shoot it if I have 1 hand on it).
The valve looks like someone set it up for either very high c02 usage of HPA. Thats a pretty standard way I have seen alot of them modified.
If you want increased performance but with the stock valve you can most like get alot from a few mods:
-barel port can be enlarged
-Probe the bolt or enlarge the existing bolt for better flow
-Polly seal
The stock valve can be modified for increased flow pretty easliy and still maintain realiability.
If you get a new valve I would remove the filter and screen as they are know to come apart and make the valve fail.
With a dremal you can also port the brass head of the valve for better flow (does nt take much) and since you have a qb79 remove the piecing pin.
I assume you have your PAL as it looks likw you need it with the existing setup.
What is your hammer spring like? It could also be cause your gun not to fire if it has got too weak.
If you are worried about CO2/air usage a HDD would help alot.
Bruce
instaled oem valve from, Eric ar S&A and it's working fine getting same FPS then I was with modded valve.
Good to hear! I expect you are HPA if it did not make much difference? It will flow much easier than co2.
You might also with HPA need to do some optimization tuning for air usage. You can often quiet downt he gun and not loose any fps... this can be done with a smaller tranfer port/breech diameter or lighter hammer and hammer spring adjstments... it all give and take and lots of playing to get things were you want.
What PSI hpa? 850 or 1000PSI?
Bruce
hpa stock paintball tank 850 to 900psi
Posting Permissions
Reply With Quote
