I've put about 500 miles of very easy driving on my newly-rebuilt B-20 and decided to change the oil (and filter) for the first time. It runs fine, but can't tell if some engine noise is normal or piston slap. Due to use of an old stock thermostat and a hard to find coolant leak, I'd had some minor overheating along the way, but nothing that really pegged the temp gauge off scale like the heat spike you see when turning off the engine in summer. The magnetic oil plug had a few grams (about a big thumbnail's worth)of metal on it with several splinters 1.5 mm or less in length. Not bad, except I can't imagine multiplying this amount 6x to 10x to compare with what I've typically seen on a 3-5K mi. oil change on my other car's 180K B-20. Should I be afraid? Is this good or not good news on a rebuild?

How much & what kind of material typically shows up on a (IPD) magnetic drain plug? What are you guys seeing?.