C172 Pilot reported incorrect maintenance procedures and failure to follow the manufacturer's recommendations not followed during engine overhaul after a propeller strike and a sudden engine stoppage. The aircraft was removed from service until repairs can be made.

Narrative

We recently changed A&P mechanics to Company in ZZZ; from the local A&P at ZZZ1. This was part of our re basing of the aircraft to ZZZ. As part of the Date annual inspection conducted by the A&P mechanic at ZZZ; it was just brought to my attention that there were several missing AD and other logbook entries for my aircraft. I was assured that these were in place by the A&P mechanic at ZZZ1 who signed off on the annual for the aircraft in Date1; as well as by my co-owner of the airplane. However; I know this is a shared responsibility under 14 CFR 91.403; and so will work to get into compliance ASAP. Separately; I was just made aware of potential deficiencies that would have made my aircraft unsafe to fly following the 2021 aircraft engine overall by the ZZZ1 A&P. Details below: Subject: Re: IO-360-L2A Engine Overhaul Name and Name1;When a propeller strike inspection is accomplished Lycoming Mandatory Service Bulletin 533C requires that all the steel rotating parts be inspected and magnetic particle inspected. The crankcase; accessory housing; and oil sump are liquid penetrant inspected. It looks like some of the steel parts were done but not the gears. None of the aluminum parts appear to have been LPI inspected. The AD requires the replacement of the crank gear bolt and lock plate which are not listed. The lock plate would be included in the gasket set. You would have to see the yellow tags to see what work was performed by Name2 on the parts sent to him. When you are working on a Lycoming engine there is a Service Bulletin 240W that lists parts that need to be replaced when they are removed regardless of condition during repair and overhaul. It looks like the parts replaced for the propeller strike were done with the exception of the magnetos. Magnetos should be disassembled and inspected or replaced after a propeller strike. If it is called an overhaul; there are parts missing from the entry. Hydraulic tappet plungers; fuel pump and fuel pump plunger; thermostatic bypass valve; and the crankshaft gear bolt. If the clamps or some of the clamps were missing from the fuel injection lines then the AD 15-19-07 was not complied with and any fuel lines that are missing clamps have to be replaced regardless of condition. It is not a requirement from Lycoming to overhaul the fuel system at engine overhaul but usually the fuel system manufacturer says it is recommended to overhaul them. If you see hardware that is not correct on the engine then it may not be torqued properly and camshaft and crankshaft bearing clearances may not be correct as they rely on proper torque. Let me know if you have any other questions after you read this. Sincerely;Name4Chief Inspector Company1 Part 145 FAA Repair Station Number [Number]Company1Part 145 FAA Repair Station Number: [Number]Hi Name4;I am hoping that you can help me out? We have a new customer with a Cessna 172S with a Lycoming IO-360-L2A with a recent questionable field overhaul. Would you be able to take a look at the overhaul log entry that I have attached and see if anything jumps out at you? FYI the mechanic indicates that it is a 0-360-A4M in the log entry. The aircraft and owner is new to us and is here for an annual inspection. FYI; Company1 overhauled this engine about 4 years back and we installed the engine and have not seen it since. Since then it has had a prop strike and was overhauled in the field by an A&P who is a local well-known hack. During our annual we noted that the mags were the same serial number units that you had installed. Upon further investigation we noted that the Slick tamper seal is still on the mags indicating that they have not been disassembled for a prop strike inspection/overhaul. We also noted that the fuel system is also still the same system that you had installed. There is no mention in the log entry that the mags or fuel system was touched. Is this a requirement for an overhaul? Additionally of the fuel injector line clamps were missing when the plane came in as well. We have found all kinds of non-aviation grade hardware store fasteners throughout the airframe and engine intake pipes. This made me look much closer at the engine. The crankcase half and oil sump bolts are from the hardware store and are not OEM Lycoming and it gives us concerns about the engine internals. Secondly I am not fully up to speed on the requirements as to what must be accomplished for a Lycoming engine in order to call it an overhaul. I am trying to craft a plan and gather enough ammunition and negative facts about the engine and things that were not accomplished at the overhaul to present to the customer. My overall goal would be to remove the engine and have Company1 perform an IRAN if possible mainly because of the lack of confidence in the engine and overhaul. Any help that you could provide would be much appreciated. By the way; the engine was running at the time of the prop strike. The propeller hit the ground during a landing according to the owner and the propeller was damaged and prop was replaced. There is no mention of AD04-10-14C1 or the crank gear bolt lock tab parts replacement. The yellow tags mentioned in the log entry are also nowhere to be found. We are going to try to call Name2 to see what they could provide for history on these parts as well. The customer has called the mechanic who did the work and he has declined to provide any assistance at all.ThanksName5