Old ford pump got some wear

[Shadow_storm56]

We left one our water pumps to a friend last fall for an emergency as his frost pump sheared the shaft off. Diesel engine and he had to almost full throttle it to do the job as it's not a high pressure pump and he needed high pressure. It had to run like this for days in end but survived and still seemed to run normal. Heres whare my concern comes in, the drain plug magnet had lots a metal on it and quite large flakes. The oil has a hint of a silver color when you drag your finger through it so I did an oil filter autopsy and found nothing. Like perfectly clean of any metal or debris. This to me seems odd as it should definitely have picked up atleast a tiny bit of debris or metal specs in normal operation but there was nothing. Another mystery