Well I picked up a can of this Top Engine Cleaner today, and followed the instructions, except that I let it soak for an hour rather than 15 mins.

Started car up and ran around the neighborhood pissing neighbors off with all the smoke. Pulled into my driveway and popped the hood, and heard a very disturbing sound -- that of metal to metal clanking coming from the valve cover.

Is this sound normal after using this stuff, and will it eventually fade away? I also noticed that I blew about a quart of oil in that plume of smoke. I sure hope I didn't damage my engine.

~Paul