I just got an engine running that I rebuilt a few months ago. I just put oil in it a couple weeks ago. I fired it up tonight and ran it for 30 seconds or less, at which point I noticed my oil was the milky color of water and oil mixing. I want to know from the experienced builders if running the engine for this long will have damaged the engine already? I'm going to drain the oil and swap the filter tomorrow... But, am I going to have to pull the whole thing out again?