Hi All I've read several threads that suggest Ferrari used Magnesium Alloy wheels for the 328, and therefore when repainting specific primers are required. Mine are what appear to be an original set of Speedline wheels. On the back of the wheel, amongst several other numbers, it states AL Si. Does this mean my wheels are not made from Magnesium Alloy but Aluminum Silicon? Therefore, for repainting, Aluminum wheel primer will be ok? Thanks for any advice that I can pass onto the painter.
Yep, Aluminum-Silicon alloy. I believe that the number 7 that comes after it indicates 7% silicon. Here's some reading about alloy wheels - https://aluminium-guide.com/en/litye-kolesnye-diski/ According to that article, "these alloys also have various additive amount of magnesium to provide good combinations of strength and ductility." I know these 328 wheels have magnesium in them, as do the forged aluminum Porsche Fuchs wheels of the same era (11% magnesium in those, I'm told), but exactly what the Mg content is and whether or not they need special primers and methods has been debated extensively on Fchat with no definitive settling of the matter. Someone needs to sacrifice a wheel and submit it for metallurgical analysis. Maybe that would end the debate.
