I finally got back to Seattle on Thursday after 8 months on the road. After unpacking and getting settled in, I decided to replace my pushrod seals that have been pissing oil since mexico. I pulled the top end off and found some pretty impressive carbon buildup in the heads and on the piston tops. I hit it with WD and degreaser and let it sit in an attempt to loosen it up, but it was baked on like cement. A neighbor across the street who is a retired mechanic recommended using oven cleaner. Sure enough it worked really well, but discolored everything pretty seriously. Only AFTER I did all this did I go online and found all sorts of dire warnings against using oven cleaner to clean off carbon deposits as it attacks aluminum. Luckily I didn't let mine sit over night as the instructions tell you to do. They were only exposed for about an hour per piece while I was brushing out the carbon with a brass brush and were then rinsed well with water, dried and sprayed with WD. My question is: do (did) the pistons have some sort of antifriction coating on them that I have now removed and if so, how bad is the damage? I remembered seeing that the piston skirts appeared to be coated with something as it had visibly worn off on the tops and bottoms of the skirts.