Just 300 km ago, I rebuilt my 7 bolt 4g63 in my CE9A evo 3 with ACL race bearings and forged internals. The crank was the original one, and when I got it back from the machine shop, it had a bit of uneven wear on the thrust bearing surface. The shop assured me the surface was fine, so I ran the crank.

Fast forward to last week, and the engine began cutting out when clutched in. It has ~ 2 mm crank endplay, and I've pulled everything apart. The crank has gone through the copper surface of the thrust bearing, and is into the steel. There was no contact between the crank and the block.

I just paid quite a bit getting this block decked and bored over only a month ago. I have an Eagle crank now, and want to make sure I don't have any more problems.

After researching online, some suggest once a block crankwalks, its no good to reuse (but provide no engineering standpoint backup as to why this would be the case), and then there's quite a few others (including shops who've given input on the subject on the dsm forums), who say the block is perfectly fine to be used with a new crank and main bearings.

Anyone with some first hand knowledge on this?

Unless someone has some actual reasoning as to why the block would suffer (heat distortion maybe?), I'd be inclined to pull it down to the bare block, pressure wash the whole inside/oil pump, and re bearing it with the new crank.