Well I was using OS 91 FX, the break in was done with 15% nitro and 20% all castor oil from sig.
It started to make friction noises right during the break in, people at the field said its normal for this engine and it was flying normal but didn’t reach high rpm, the airplane is 4*60 so I didn’t need much performance from it.
Fuels I used: Sig 15% all castor (two cases), Omega 15%, cool power 15%.

I’m not a beginner any more to know to run the engine on the rich side and to use after run oil at the end of every flying day.

The friction noises continued but it was flying well, now 9 months later at the end of the flying season I decided to send the engine for inspection, I’m getting this bill of repair:
• PISTON 91FX
• PISTON RING 91FX
• CYLINDER LINER 91FX
• REAR BEARING 61-300
• PSTN PIN RTNR 61RXSX

How do you ruin all these parts if you are not running it lean is beyond me.
Speaking to the hobby services they said maybe I didn’t use after run oil, totally incorrect I’m using after run oil religiously a lot, than maybe you run it on high RPM – also incorrect this airplane doesn’t need high RPM I was using 14x8 prop.

Hobby services said OS wont accept it under warranty.

The total is nasty almost the price of a new engine.
I don’t think I did something wrong especially the friction noises started while breaking in.

More important why pay the price of an OS if the warranty is so bad, or what did I do wrong?

For your thoughts and input.

Thanks
Alex