I have heard speculation that it has something to do with the crank vaporizing the oil at that level when run hard. Which would explain the particulars of the problem. I don't know myself why it happened.
I can tell you that I have seen it many times. On stock engines in particular. We used to have to keep a sharp eye on our oil level. It needed to be about a quart low in order not to be adding oil regularly. At the same time, we didn't want it to get much lower due to the risk of losing oil pressure under hard accel or decel. Fortunately there usually wasn't much change when kept a quart low unless the engine was getting tired.
But the top quart of oil in big blocks had a nasty habit of exiting the engine some way or other. I have never experienced that with any small block. Has anyone experienced that with the small blocks?
Something I thought of was the oil being thrown up into the bores by the crank, and that somehow got past the rings a bit at a time. Being that it was more oil than normally gets there. I’ve never heard this about other brand cars and really this is the first I’ve heard somebody else notice it. I told the people when I sold that car and they just sorta looked at me funny.
Also I’ve never had a small block do it. Had a 22,000 mile 79 truck in the mix. Others were high miles, but they didn’t use any oil and even didn’t leak like big blocks seem to when I get them.
