After more than 10 attempts, I have never completely stopped the valve cover leaks on my 50° AAZ. Yes the cover is perfectly flat. As for sealer I put dabs, no dabs, full seal, different brands (Right Stuff, Permatex Hi temp, etc.) - no joy.
A few days ago I ordered another brand new gasket set (Elwis) and figured I make another attempt. The first thing I discovered when I went to remove the valve cover was the grommet that seals the breather (typically called the "hockey puck") into the valve cover was in bad shape and not sealing very well - yes, it was leaking as well.
As I have built a custom intake which made the hockey puck not fit well, I had fabbed up a different breather affair and have been using this (with a catch-can) for several years. This was part of the grommet sealing problem as my home made unit didn't have the same barbed fitting profile as the plastic hockey puck.
This time, when I had the cover off, I decided that one of the problems is because the engine sits at 50° the hole for the hockey puck is on the down-hill side of the valve cover. This location is also why the stock breather wont work (in my case) because it's too close to the manifold tube. So, I cut a new 1" hole and brazed in a short tube so I could attach a 1" ID hose. The hole is located at one of the areas of the valve cover where it has a secondary chamber on the inside. The hole for the hockey puck is located in a similar place - just on the other side.
I cleaned both the sealing surface of the head and cover till they shined, and wiped them with lacquer thinner. The gasket fit perfectly and I thought I'd try to see how things went with no sealer at all as I had read that some had good luck with this approach. I torqued down the three nuts according to spec and installed my new, very simple breather. This simply consists of a 1" tee fitting, a very short piece of 1" hose (T to valve cover, a 1" hose from the block breather to the "T", and another 1" hose from the "T" to the catch can. The catch can is simply a plastic bottle with a 1-1/2 neck. I have never had any liquid oil in it but it has turned black on the several years I have been running it.
Anyway, after I got everything assembled, I started it up and let it sit and idle till it came up to temp. I was surprised to see I had zero oil leaks! I must say that I still didn't believe I had solved it based on past history but still, I was hopeful.
This morning, I wrapped up everything, pressure washed the oil stains off the driveway, and took it for a quick spin. When I got home, I took a quick glance under the van and it's still leaking
At this point I am wondering of the 20 lbs of boost (which I wouldn't have with it idling) is somehow making it's way past the pistons and producing more pressure than the 1" hose can dump - making the oil actually blow out from between the valve cover seal. I know this sounds crazy but I just don't understand why this thing is so hard to seal. I also wonder of there is something about the stock hockey puck that makes not using it create some issue that would make the cover leak like this.
Here are some pictures of what I have - BTW, I brazed the stock hockey puck hole shut. Also, the weird thing in the upper right of the first photo is the contraption I made to replace the breather. It is filled with stainless steel scrubbing pads. Now all I have is a "T" fitting.
I am totally stumped and would appreciate any insight from the group. Thank for reading my novel
Jim