17-03-2021, 10:02 AM
(17-03-2021, 09:12 AM)JonE Wrote: Could re-linering take away ALL the duff material in the centre area of the block, creating an efficient waterflow, but just using the top and bottom of original block to affix the liner?
Yes! In this case, as I said in a reply to an earlier thread about head gasket failures, the block becomes structurally weak if the bores are corroded away (the bottom face is no longer connected to the top) and the top face then distorts, leading to gasket problems. Dave Williams (Austineers) has a block, sectioned to show just this problem. So there must be enough of the original bore material left to provide structural integrity.
My own experience, over the years, is that there is more bore material in early (vintage) blocks and the material is better quality. Early blocks will usually (not always!) bore to +80 or +84 (for slipper pistons), whereas the later blocks often start to get thin.