First off, make sure you are running Straight 30 weight oil. If not, change over to it. Second, don't block that passage in the york crank case to the head. That passage is what allows the crank bearings to stay cooler during operation by allowing oil to pass over them.
Take a look over my tutorial on the york on my site. Its not complete yet (once school is out I will finish it up), but you get the idea for the most part. All I haven't done is installed the compressor.
http://www.airridetalk.com/tutorials/tutorials/air-on-demand/