It's a great day in the garage!
1. I got my intake valve covers back from Spray Tech, polished them up and shot 2 coats of satin clear.
Sidebar: When I picked up the covers from Spray Tech, the crew had already left for the day so Fidel gave me a detailed tour of the facility. Turns out I have been incorrect about glass bead blasting with water. The glass bead blasting is done dry, the glass bead medium is a fine white powder.
I had tried to refurbish the of the valve covers by spraying 2 coats of black, but even with sanding and degreasing before hand, the covers didn't take the paint evenly (I painted the top side only). At that point, I took the covers to Spray Tech for help.
Fidel at Spray Tech started by soaking the covers in acetone over night as he suspected the covers were not aluminum and did not want to use stripper that might damage the covers. Once most of the fresh paint was removed by the acetone and hand scrubbing, he started glass bead blasting and all went well on the topside of the cover, but when he tried glass bead blasting the original black finish on the bottom side of the cover the bead blasting produced what he called "sparks" so he stopped and left the bottom side alone.
After I got home a looked at the part number cast on the bottom side of the covers (901.105.115.0R) and compared the part number to the one listed in Appendix B of Wayne's 911 Engine Rebuilding book which listed 911/911 Turbo (1974-89) as part number 901.105.115.03 along with the comment "Verify that yours is manufactured out of aluminum, not magnesium". Given Fidel's sparking and the part number on the valve cover leads he to conclude my intake valve covers are made of magnesium. Everyday is a school day.
Intake valve covers from Spray Tech, after polishing, and after 2 coats of satin clear coat:
2. I got a present from FedEx in the form of 2 rather heavy boxes from Craig Garrett (cgarr) from G2 in Grand Rapids, MI. Craig rebuild my heads, rocker arms, and cam towers and they look awesome! Thank you Craig, and thank you Al for recommending Craig to me.
