I purchased the Quick Oil Drain (F 50) from Safair for my Arrow, tried to install it, but it won't seal! At some point in time in my Airplane's life, something was added to my oil drian with a lip that stops the Quick Drain from threading in all the way. I called Lycoming and sent the tech support guy pics and he had never seen anything like it. It looks like it is Glued to the Oil Pan and the lip extends down past the oil pan. Has anyone else seen this or have any idea why someone would add this to the oil pan? Should I try to remove it? Engine is a Lycoming IO 360 C1C in a 1974 Arrow. Pics attached!