15w-40

[noboD]

1929, read an article written by Lake Speed's son. He is the oil Doctor for Hendrick's Motors in NASCAR. He claims engines should be broken in with NON detergent oil. His reasoning is detergents and zinc "compete" to attach to new engine parts, like bearings. After the zinc attaches itself during break in then switch. He explains it in very clear terms, article should be able to be found online. I read it in a engine rebuilder trade magazine.