Check the positive crankcase ventilation system-start at the PCV valve

Change the PCV valve. When the oil heats up in the engine it starts to smoke and build pressure. This is normal. That pressure is relived by the PCV, and the smoke is fed into the intake. The catalytic converter takes care of it before it leaves. Should be a small hose that runs from the valve cover to the side of the intake somewhere. On the valve cover is usually where the PCV is located. Pretty inexpensive part and can usually be changed with a pair of pliers. I recommend changing the little hose as it can get gummed up as well. Good luck.