That's what I'm thinking as well. All motors do it slightly during break in but I just hadn't seen any visible trace metals since the 2nd change. Also, the 4.7 is cast iron. The new 4.0 is the all aluminum motor..

 

What about the 2.7L? Is the block iron or aluminum?

 

Iron block too


My guess is that the particles are part of the motor breaking in.
They have ikely remained in the pan since break-in and they happened to come out then.
I really would not worry about it in the least.

 

No matter if it is an aluminum block, the cylinder liners are always iron. Too much expansion with alloy to use in direct contact with the pistons.

Unless they are doing something different, aluminum would not be present in the seal between piston and the walls of the cylinder.

 

Aluminum expands alot quicker then iron does so if that was the case the piston rings would lose their seal with the walls of the cylinder.

 

The rings would not loose their seal, in a way their like springs that expand and shrink slightly to adjust to the specs of a cold block verse a warm/hot block.

http://www.totalseal.com/aolnav4.gif

It don't matter if the block is aluminum, the cylinders have steel sleeves like FirstToy mentioned and the crank, camshaft, bearings, and any other part that moves is made out of steel or cast iron etc.. and will stick to a magnet.

My engine has similar looking stuff in the oil, thats why I try never to look to close.

 

Your avatar is scary bro..