Yes, I masked off the cases and painted them. Lots of blue and green tape.
After many cleanings, gasket surface cleaning, oil passage cleaning, flushing with acetone, denatured alcohol and simple green, tapped out holes, cleaned again………..I taped it all off. I have a small lazy Susan I paint on, that way I can turn the piece to get around to the other side.
I kept my wood blanks that I used for bead blasting if you are doing a Z1. They are crude but they mostly worked, I didn’t find glass inside except for one area around the starter. Before blasting I cleaned the cases in Simple Green, removed as much paint as I could with Citrus Strip, pressure washed and soaked in Simple Green again. Then I masked off with yards of green tape, then I put the blanks on. This engine had been painted over by the PO so it had very thick paint, it was a real chore but it came out ok, I’ll post more photos soon.
By the way, I have been spraying the acetone and alcohol with these glass spray bottles I found at Target, they work well.