I posted here earlier in the mechanical section about a knock my car a 1999 sentra is making and the sludge buildup I found in the engine. I asked my local machine shop for a price on machining my head and crank. He said it would range from $800 to $1500 dollars, which I thought was way high. I then went to my local junk yard and looked at some cars with the engine I need. I found one with 160,000 miles that looked like [censored] on the outside but when I took the oil fill cap off and looked inside at the camshaft and surrounding area it looked brand new. Not a sigh of any discoloration. The metal looked as if it was new. The only problem is that they leave the hood up and the spark plug holes had water in them. I am going back tomorrow to remove the water from the sparkplug holes and take the valve cover off. If the engine turns out to be as clean as it appears I am going to try to track down the owner of the car if the registration is in the car and ask them what did they used for oil as I have never seen an engine this clean, I will try to take a picture.