Sorry to bring up the oil topic, but I searched the countless threads for any mention of a rust inhibitor.

My girlfriends' cousin's husband is an engine builder and drag racer. I asked him what he thought of Mobil 1, and he mentioned the time when he had 2 cranks side by side when he was doing a build.

He had one crank that used Mobil 1, and one that used Penzoil. The crank that used Mobil 1 was "stained", or rusted. He said that he could not get it off.

Anyways, I was wondering if any of you knew what rust inhibitor commonly used in motor oil was. I forgot to ask him as we were getting ready to leave.

Thanks for the help.

EDIT: Should say RUST, not RUSH

 

Engine oil is not designed for atmospheric corrosion protection. It was intended to be operated in a very different environment but they do have some corrosion inhibitors. It all depends on the weight of the oil as well, the Mobil 1 could have just completely dripped off the surface.