Anyone out there running a Norvel with crankcase pressure using the Norvel screw in backplate with a pressure tap? I have 5 1/2a's on the table right now ,1 will run a bladder, 1 a balloon tank and 3 will have hard tanks. I would like to try something other than muffler pressure on the hard tanks. The hole in the pressure backplate looks awful small but that may be what it takes, maybe need a one way valve?

           Ray, I have some experience with running them on pressure. As it was shown to me, the hole required has to be incredibly small. The fellow who set these up for me explained how he  blackened the smallest music wire he had over a candle. He used small copper tubing fitted to the backplate with JB weld and he would solder the inside of the tubing and insert the blackened pin into the solder. This left an extremely small hole. As he suggested, the engine will run fine on the stock needle valve. The stock needle valve will not work properly on bladder. The smaller the hole the better and no back check valve is required. The engine is running on a 1/2A proto plane. I'm having difficulty though with the tank. It needs a little redesign. Ken

Thanks guys, i have a couple of the factory pressure backplates. I tried once a long time ago but i believe i drilled the hole larger,didn't work too well. I will give it a go with the standard hole once the weather breaks and give a shout back how it worked.