I thought I would start a new thread for this inspection. As you know I have lower than normal oil pressure on a TIO-540 and I after painstakingly eliminating all of the items on the troubleshooting list I finally removed the accessory cover and opened up the oil pump. I discovered a damaged impeller drive shaft and the 61297 impeller (see attached photo). First Question: What could have caused this shaft and impeller to get so worn out in only 170 hours since these parts were new when the engine was overhauled??? Second Question: Could this this worn-out shaft have been the culprit for low oil pressure or is it just an impending failure that has not been revealed and I still have some other problem? Third Question: Since I have the accessory case removed what other "usual suspects" should I be inspecting? Forth Question: I know that since the airplane has an oil operated turbocharger that I should get a high-volume oil pump. Does anybody know what part numbers I should get and an economical source (I am OK with "experimental" parts)? As always Thanks for your help!