1. Worn Piston Rings - Worn piston rings can't properly seal, which can cause excessive smoking and oil consumption. The engine will usually still run okay.
2. Worn Valve Seals - Worn valve seals can stop oil getting onto the vales but allow it get through when accelerating creating large amount of white/blue smoke.
3. Clogged Positive Crankcase Ventilator (PCV)
Valve:
A clogged PCV allows pressure to build. In some car with PCV valves built
into them this pressure forces them out as air and smokes through its hose and intake pipe.
