If you lost the ball in the valve thats your problem. Your just breathing in the air that is coming through the valve. It wont make noise because the smoke/ air doesn't ever really reach the water.
check out http://www.hookahpro.com/forum/showthread.php?t=2744
You can possibly make one or use something else. I've never had to do that, but maybe someone else will have more info on that for you. Hope this helps