Update on this problem with lots of metal in my last filter, especially to Roger who was kind enough to help me with advice over the telephone. As you suggested Roger, along with a few others, I removed my gearbox and sent it to LEAF for a complete disassembly and inspection. This was because the gearbox was the last major mechanical item to be messed with (by a less than reputable shop) prior to the metal flakes appearing in the filter. Results from LEAF showed the gearbox to be in fine shape with only a few minor adjustments required, and definitely not the source of the metal flakes. So I reinstalled the gearbox back on the engine, still not knowing the cause of the metal flakes.
Here is what I decided to do: With a new filter installed, I flushed 3 oil changes thru the engine, running each oil change for about 1.5 hours on the ground with high speed taxiing, then drained the oil and refilled 3 times, all with the same filter. After the last oil flush I removed the filter and cut it open to inspect. It looked great, like it always had before, with only about half dozen very small non-magnetic flakes-probably aluminum. So now I have confidence to start flying again, which I did yesterday for about 3 hours. All sounds, performance, and engine instrument readings are completely normal. I plan to continue flying carefully, at higher altitudes, no passengers, no mountainous or inhospitable terrain, near airports and fields, with careful instrument monitoring. Maybe for 25 hours rather than my usual 50 hours oil change interval, after which I will again cut open and inspect the filter.
I am beginning to think that the high metal content in the filter right after that un-named shop serviced my gearbox and replaced my rear ignition housing was a one-time unexplained event that does not appear to be continuing. Time will tell, but what do you all think? Am I crazy to fly it? Any other thoughts on a probable cause? I thought of one thing: I didn't mention it in my engine history on the first post, but that same Arlington, WA shop sent my engine back to me with two wires crossed up in each ignition module 6-pin connector, so it wouldn't start. After many, many crankings requireing two battery recharges with no starting success, they finally, after 2 months figured out the wiring mistake, and it started right up. Could it be that all that cranking time with no start caused a high wear rate due to low oil pressure during cranking? Maybe in the starter area?
Sorry for the long post, but I am still looking for answers short of a complete enging teardown.
