Let me try! Is the distance from the bottom of the pick up to oil pan correct? Is it possible the pickup is sucking air where it is pressed in or the tube has a fracture? And yes get some measuring tools! A set of micrometers that measure in ten thousandths and a dial bore gauge that does the same. You will be amazed at what a lot of shops will pass off as good machining. Nothing like double checking things yourself for peace of mind. Mitutoyo has some budget friendly stuff that is very accurate. Remember, precision tools aren't an expense, they are an investment! An investment that will pay for itself the first time you find someone elses screw up.