My B18C1 engine was completely rebuilt to OEM specs about 270+ miles ago. Only recently (maybe within the last 50 miles or so), I've noticed that a plume of white smoke would come out of my tailpipe when starting the engine. I do not get any white smoke when driving my car around after. Also, the white smoke does not consistently happen every time I start the engine, but it happens enough times to make me a bit worried. I would sometimes get white smoke after the car had been sitting for only half an hour, then starting it up. My question is what should I check to determine if the white smoke is something I should be very concerned about?