Replacing the timing belt on a 92 240. Cranked the motor dozens of times trying to get all three timing marks aligned. I could get the INT and CS marks dead on, but the Camshaft mark would never align with the molded line on the rear cover. After much head scratching I noticed that on that rear cover it appears the PO had scribed a line that did align with the Camshaft mark. This mark is about 2 teeth to the left of the molded mark. What is this telling me? Could the rear cover been replaced at one point and the molded mark is there for a different model? I'm not sure if I should keep the Camshaft aligned to the scratch mark or advance it the two teeth to the "factory" mark....