I finally started working on my car tonight, and I pulled the heat exchangers off with the engine in the car. While I was looking up at the engine I noticed that the exhaust valves (stems and heads) are completely chalk white.... now I know I'm going to open myself up here, but what causes this? Is it bad (I think it's not good, but I'm not sure)? I know enough to get myself in trouble, but I've never really gone deep into an egine before. I did take the engine out once before, years ago, but this car has just been a weekend car, so I've not really done much to the motor. I know pictures would be helpful, and I hope to shoot some tomorrow. The car runs fine, idles nicely, and seems to be in good tune, but this has me worried. Anyone have any ideas?