In the front you see the old cam cover - note how the material dissolved itself - it just "melted away - that is electro-corrosion: Magnesium loosing the fight against aluminium and steel. Behind it the new cam cover, which I sourced myself in China directly - while they did not know exactly the material, they thought it may also be part magnesium, but it is supposed to be an alloy with only a small percentage of magnesium...