It's simple to check if anything in the valve train is having a problem, just pull your push rods and check to make sure they aren't bent. Those are usually the first thing you will see. As for the compression? We had a freezing cold snap here for a while and I haven't been doing a lot of flying, I don't like the cold. When I pulled out my Extra with a YS 1.20 that engine now has a ton of compression? Runs great and when it has been started and run, there is no problem but my starter with an 18 volt battery doesn't want to roll it over while it is cold? This starter with a full charge will roll over a DLE 30 gas engine. So far I haven't found any reason for all the compression but I really haven't looked into it. I just make sure I charge up my starter battery before I go flying. I plan on flying again tomorrow so when I get home I will check the valve adjustment. It runs so well I just don't want to fool with it. It's not real cold now but it may just be it doesn't like being left out in the van in the cold weather we have at night? I also changed the cone in the starter. The old one is getting hard and not gripping very well. The new one is very soft and should work better?You may just be lucky and have an engine that is holding it's compression after the ring seated?If the push rods are OK I wouldn't worry about it too much as long as it runs well. The steel parts in an engine will rust but as long as they aren't rusted on an operating surface there shouldn't be a problem, just a sign of moisture in the air.