Most likely, on gen 2 engines, the block and sleeves are thermally fused, which means they actually make the hole on the block for the sleeve too small to fit the sleeve, and make the sleeve too big for the hole. then durring assembly, they heat the block and freeze the sleeve, causing them to change size and thus being able to put them together. once the temp equalizes, they actually fit so close they are virtually one peice of metal. the block manufacturer most likely is the only place capable of changing the temps enough of has a method of cutting the old sleve out and fitting a new one. Gen 1 engines are most likely just press fit or slide-in-place and held by the engine head. this way, just a little heat from a tourch will render them removable-(there has been problems in the past with these types of blocks on aluminum engines/iron sleeves because the coefficient of expansion is so different that normal driving temps will allow an expansion of the block enough to cause sleeve shifting. they switched to the latter style because it requires 1000's of degrees of temp differences to make a difference.) I hope I explained it well enough, if you have any more questions, please ask.
