Catching on the bottom of the sleeve...

 

Is it me or to the left of the sleeve does it look like there is a small crack? Look on the non-sleeved cylinder to the left then look at the sleeved cylinder to the left. I wonder what happened to the block in the first place

 

LOL, its a parting line from the casting... every cylinder has em... plus ive had the block checked for cracks and it was good... sure does looke like a nice crack tho hehe.