just wondering what people's experiences have been with rebuilding wornout engines. Is it better to buy a new one or just replace rod,sleeve, and piston of the old engine. I've ran a N12LL3 for over 1yr and am pretty much pleased with it. Is there anything that I need to be concerned about in rebuilding the engine and is it worth it? I found RcMushroom to have rod, sleeve, and piston for $130 vs a new engine for approximately $300. This looks easy to answer based on numbers, but it looks almost too easy.