Compression testor ?
 

Do they sell a compression testor for nitro engine's ?

and if the specs for various engine known ?

I have not looked much into this. But was thinking if there was one for nitro, I might want to get one.

Sporty

Seems pretty silly doesn't it? Take your plug out and spray some wd 40 in there then pull a couple times. Then turn the cold engine by hand.....feel any tightness there at tdc? If there's none then your engine is worn but may still have a few gallons left to go.