What are you thinking Mr Hunter? Do these heads have valve seat inserts? I have been wondering how he went from basically wide open to normal compression during the initial testing.. I cannot see an application of a light oil sealing that valve up that well. Bunker C maybe.

Although I am old enough to know that everything is not always logical progression. I even remember opening up some piece of equipment and the defective part had developed a basic face in the failure mode. . Not only that it was just sitting there and smilling at me.