I was scrolling through some of my photos and thought I’d share what motor oil ash looks like. See the cup on the right. These oils unintentionally autoignited in a test. It was VRP’s fault and it caught the other two oils on fire. VRP burnt very far to completion, allowing it to form a lot of ash from the metallic additives. The other oils burnt for a while then the fires stopped while quite a bit of the oil still existed, so there is not much ash in those cups.
The ash’s consistency is crunchy. Ash used to be important for cushioning the valves when they slammed into the valve seats. That requires a sufficient amount of oil consumption. I think it was much more necessary in the past than now, since I think the metallurgy has improved. With many modern engines, oil consumption is very low and not much ash is formed. If anyone knows anything else about this, let us know.
In the sulfated ash test, the oil is burnt in the presence of sulfuric acid to maximize the separation of the carbonaceous material from the metals in the additives. http://www.uspbpep.com/usp29/v29240/usp29nf24s0_c281.html
The ash’s consistency is crunchy. Ash used to be important for cushioning the valves when they slammed into the valve seats. That requires a sufficient amount of oil consumption. I think it was much more necessary in the past than now, since I think the metallurgy has improved. With many modern engines, oil consumption is very low and not much ash is formed. If anyone knows anything else about this, let us know.
In the sulfated ash test, the oil is burnt in the presence of sulfuric acid to maximize the separation of the carbonaceous material from the metals in the additives. http://www.uspbpep.com/usp29/v29240/usp29nf24s0_c281.html