Spray welding was the first thing I thought of when I saw the first post. I have a block that someone broke the edge off of an intake port, probably with a valve prybar. Guy I got the block from thought it was junk, little spray welding and it was good to go! I posted a thread on them fixing it a couple years ago.
talking to an old foundry worker the otherday an he pointed out something called thermal shock. where in a casting if you have a piece of block wall thats thick and that then thins out and back to thick again or just radical unneveness in wall thickness, cracks will usually appear on the thinner section as due to uneven temperature distribution with the thinner part getting hotter quicker and cooling more rapidly, this can happen after pouring whilst the block is cooling or can happen as its being used for day to day driving.I think with the origonal blocks cast in the 30s they used to let em sit an weather for sometime before machining em.
Luke 13. The crack was at the thinnest part. I am good for now, but I am curious about the spray welding. I never heard of it....Taker easy fellas.
My mill is out being mag-ed right now, I'm hoping to get a clean bill of health, but if it does have cracks and is something I can't pin myself, then ill have Joe spray weld it and I'll see if he will let me video him doing it.