Now be aware these are Wisco OMC pistons that were also finger ported.
This is one of many pins that I have had come out. This one more then likely cost my wife and I a WON Bass team championship at Shasta Lake years ago. It was after this I had the next three sets of pistons top pinned.
The first set I sent back because the weld where the EDM penetrated leaked. I found it when cleaning the piston before assembly. Using air pressure to dry the piston, I noticed bubbles coming out the old pin hole.
This one I caught in the act.
Note the area on the side of the piston where the pin is. It's filed down a little because I found the cylinder wall scored directly where the pin was. When the pin is pressed into the piston the aluminum pushes out.
You can also see that the pin was moving at some point when the piston grew and the pin was still cold and still small?
I remember talking to Al Stoker about the pin problem and he said Chrysler OB's used a roll pin and he had never seen one come out. Neither Dave or Al have had pin problems. The pistons in the original 3.3 build were out of one of his drag engines and the pins still were good when the engine was torn down.
