Tried a new method of cleaning and shining the Z free air engine. I used to use crushed glass or sand to initial water blast clean the whole engine. Then glass bead water blast to smooth and polish the engine to a satin smooth finish better than factory by far. This time I went with crushed walnut to clean the engine as walnut is softer than the aluminum so I hoped it would result in less of a rough finish before glass bead water blasting. Then glass bead blasted the entire engine and carbs. My theory worked excellent so decided to post the results. First 3 pics are before pics.