So my B that I have had for about 9 yrs has always had a motor knock and is slow to build oil pressure when started if it has sat for a couple days. Air temperature does not matter. I don't rely on it for everyday use so I never got to worried about it. Sometimes it might get started every day for a week (rarely) and others it might go a month between starts. I have done regular maintenance to it and did a paint job a few years ago. This past summer my dad and I pulled the pan and the oil screen was darn near clogged. (I will attach pictures) We shimmed and reset all bearings in bottom end, none of which had any abnormal wear. After all this and a clean screen I figured the cold start knock and slow pressure build would be gone, however it remains. I am wandering if maybe the oil pump might have some play in it causing it to be slow to build pressure. I have no problem splitting the tractor to check it out but just thought I would see if anyone else had any other ideas before I did.