A Tower Hobbies engine should not have any abrasive compound in the engine when it's new. If it did, then it should be returned for exchange. Likely, the factory messed-up, or the returns department messed-up and sent you a previously-sold engine. We get people all of the time who think a tight, ABC-type of engine is defective because it's tight at the top. Some people actually try to "rectify" this by trying to lap the engine or otherwise re-work it. Some will then return the engine as "defective", even after they've tried such rework. Occasionally, the returns department might miss such an engine...it depends upon what is written in the return letter. .....Yes, some people will "bend" the story a bit in hopes of getting the engine returned.