The bearings still look and feel fresh and the cylinder still had swirl marks in it. I got 1 used a few weeks ago with a 600N and pulled it apart to check for wear. It's no 55 or 56, it's a 53, I'm thinking of trying one of the newer pipes for the 55 on it and see how that works, may just get another 10th or two of hp and tq? I just buttoned it back up and will fly with confidence. There is no pitting, no rust, no notchyness or any of that. I don't mean to rank on the OS engines but the quality issues thread that is in this forum got me to looking at my 53 thinking this thing should need bearings by now but it doesn't. I've got no complaints about this engine. I fly with a headspeed of 2060 to 2170 depending on how much power I want at the moment but mostly on the higher setting. It all looks good for as many hours it has on it. I've had a set of bearings in the parts box waiting to replace these stock bearings and it still does not need it. After many gallons of use I just checked the bearings and they are fine, no rust or any sign of needing replacement.
I started it off on %20 cool power, then went to %30 cool power and now I'm using Wildcat %30 Helimix (there is a difference between the wildcat helimix and performance blend, I prefer the Helimix). But that got me to looking over my old TT53, it's a year and a half old and has many flights on it. There's a lot of buzz about the new 55 & 56 and by all rights there should be.