Caps are cheap, and available at your local aftermarket parts place. Start with that then.

 

If he had a hole in a piston it would be coming out alot more than he is describing. Also it would be leaking out the back too. Mine was.

 

yeah and blow it out the dipstick

 

yup that's what mine was doing.

 

My dipstick stays put, doesnt seem like it's leaking out the back? The cap is screwed directly to the valve cover.

 

Do you still have the filler neck that goes between the cap and the valve cover? I recently installed a cap meant for a filler neck directly onto a valve cover and it blew quite a bit of oil out. Once I put the filler neck back on the problem went away.

If they make a cap designed to attach directly to the valve cover then you might be able to try that.

 

Remember that FI will create positive pressure in the intake. So, if you don't change your pcv system (Add check valves or something) you will blow out valve cover gaskets.
I did this when I first put my whipple on. Air from the intake backfed into the valve cover and caused a big leak.
I could see this happening on the filler cap as well. We need to figure out were the pressure is coming from that forces the oil out. If nto coming from the intake side via a pcv hose, are your rings letting that much pressure blow by?

 

God I hope its not the rings. Would it be better to run my catch can from one valve cover to the other, then put a filter on top of the oil cap to help it breathe better?

 

First look at the entire system and make sure you have nothing blowing air into the valve covers. Then, put a breather on the oil cap as a way to relieve pressure in the case. The breather is a bit of a band aid. It will help for sure, but you still don't know were the pressure is coming from.

 

IDK if you saw my sig, but I'm running about 12lbs of boost on the 5.3 with 918 springs and pushrods. Which is about the extent of it. Here is a little info on the breather/catch can setup.

The back port on the passenger side valve cover is capped, the front port on the pass. cover has the STS check valve on it going from the valve cover to the intake. The rear driver side port on the cover goes to the catch can, and then goes to the top of the intake and the front port I believe is capped off too. Think its just because its not being vented well at all?