I have been told that cleaning aluminum engine parts with glass bead is not a great thing to do. The glass beads will embead themselfs into the pours of the aluminum. When the engine is assembled and run the aluminum will expand releasing the glass beads and causing un wanted engine wear. I do not know if this is true but sounds logical to me. If this is true what would be a better choice of media to clean aluminum? Would this also be true for cleaning cast iron such as blocks and heads? What would be the best choise of media to clean cast iron? Glass bead has a very low errosion effect on critical surfaces like bearing journals. How would a steel shot affect these areas? Thanks for any information
Jeremy

Your suspicions of glass embedment are probably well founded. Glass bead breaks at peening intensities above .006A. You might consider using stainless steel cut wire media. It is very durable and won't leave contamination like glass bead or cast steel shot.

Also, are you only cleaning the parts or are you also seeking a peening benefit?