Removed the timing chain cover and oil pan (about 12 hours) and found the plastic facing on the timing chain tension had worn and broken off. Parts of plastic blocked oil at the pickup tube and the bits of aluminum in the oil filter were from the bare face of the tensioner being worn by the chain. The oil pump on this engine appeared bullet proof to me. Ordering new parts for re-assembly.
'00 Mazda MPV Family's car
'83 300D 235,000
'84 109E 175,000
'74 280C 125,000 in garage; needs rehab or sell for parts???