Bought this tractor couple weeks ago. Had a knocking sound in it. Changed oil in it. there was probably 3 inch of gook in the bottom of the canister. the old oil filter seemed to weigh couple pounds. oil was the blackest ive ever seen. not sure when he ever changed oil in it. He said it just started knocking and the tractor place told him it probably wouldn't last long. I finally took the pan off. nO 4 Rod seemed loose. Pulled bearing cap and there was a big problem. bearing had spun and what was left was more of a tin piece. Had to use a screw driver to pry it out. Journal looks good so I am going to put a new set of bearings in it. Anyone know the part number for the bearings for an 8n. Don't think the motor has ever been worked on. ive seen some on ebay but they talk about 20 and 40 thoudsands. just don't know which I need. its a 1951 8n ford. thanks norm