Fixed

 

I know sleeves have their place in the world and if properly engineered may be okay for certain applications. Sometimes they can even help overcome some poor engine design features (like really thin walls on overbores) when pushing boundaries of the performance envelope. But in my mind its yet another variable that has to be managed due to dissimilar metals, coefficients of thermal expansion, etc. I'm with hi_im_sean. I'd much rather have a Nikasil lined cylinder (or viable alternative depending on the exact metallurgy of the casting).

 

It's not really that they "may be okay". Sleeves are used all over, in performance and non-performance engines. I think you're overthinking them.