Before you do anything, first pull the serpentine belt and start the cold engine ... just to make sure that the smoke and the noise are related.
If you suspect the valve guides, try the suggested 'Timing Light Test' to distinguish between valve train and lower end noise. I've used this before to ID a worn rocker arm and it really works.
"Diagnose Noises with a timing light?
Valve train noises occur at half of crankshaft speed so even if your ear can't tell whether the noise is happening at 700 rpm (raps per minute) or only 350 rpm, your eyes can. Hook the timing light to any one cylinder and watch the flash illuminate the timing mark. Stare at it for a while and see if the flash jives with the knock. If it does, then it is more likely to be rocker arms, pushrods, lifters, camshaft, cam bearings, timing chain and gears. If the noise seems twice as fast it is probably in the crank, mains, rods, rod bearings, wristpins and pistons."
Also, from the next page (Engine Noise Diagnosis 102) of the original link:
http://www.remanufactured-engines.com/page5.htm
"When the engine is cold, the aluminum piston is small in comparison to it's iron cylinder. Therefore the rather hollow slapping noise will be loudest first thing in the morning. After the engine warms up, the aluminum piston heats up faster than it's iron cylinder, cutting down on the excessive clearance between the piston and cylinder wall."
