My father sold oil for the company that developed ZDDP in oils in the 40's. When I was a kid, I would ride along with him when he called on potential customers. As a demonstration, he would have me crawl under the old GMC pickup and let the oil into a wash tub. He would drive about a 100 yards, turn around and put the oil back in. That sold a lot of oil. I still sell lubricants. I now like a moderate detergent oil in my old jalopies and I add this.
http://www.zddplus.com/ I don't care for oils designed for Diesel engines in my old engines because they are more focused on holding Diesel soot in suspension than to cling to metal parts.
