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I think I'm gonna go for a repair on my block.

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That "crack" can be what's called a "fold" in the surface of the casting. If the material is thick enough it is only cosmetically annoying. It -can- be a stress riser if it goes more than a third of the way in. Happens as the molten iron contacts the mold, cools more at the contact surface and "drags". If that were a part to be machined it would be different. As it is, if dye penetrant or Magnaflux tested and found to be surface only, don't fret.
 
I use to do nondestructive testing at an engineering firm, and you can get whats called non relevant indications from flaws like that in magnaflux or magnetic particle testing, to really be sure if its a crack you can get an angle grinder with say 120 grit sand paper and slowly start to polish the crack/seam out, test and sand till it goes away, if it is a casting flaw and been there this long, I doubt it will cause you any trouble and not likely to crack unless you hit it with a sledge hammer. Also they have new welding rods made especially for welding cast Iron that work great.
 
That can be and is a stress riser, even with the small incursion. It of course makes a difference on how stressed the block is at that point if it would be a problem. It will never be a race engine, but if it's not a crack it will work well as a street engine. Don't expect dye penetrant to show a crack there, or even eddycurrent. I would leave it, or if the machine shop is worried about it, weld over it
 
2wrench said:
Actually, the machine shop and the "block shop,"told me: "Stop worrying." They say they won't just
jump to good to go, but it does look doable, in their
first-blush look-see.
Click to expand...

Excellent advice from what sounds like a top notch and ethical shop. They've got a lot of experience here, and it really sounds like they are being very honest and thorough for you.

Trust them and proceed.
 
I know a few guys who have had blocks that were beyond saving or they didn't want to gamble on them. When the replacements were being line bored, machined, and balanced a common practice is to shave the deck, or mating surface to the head. An important tweak to building a good engine.

When the block's deck is machined, the numbers on the left rear are removed on that flat area by the process. Matching numbers are sometimes engraved for the original engine.
 
hondo402000 said:
I use to do nondestructive testing at an engineering firm, and you can get whats called non relevant indications from flaws like that in magnaflux or magnetic particle testing, to really be sure if its a crack you can get an angle grinder with say 120 grit sand paper and slowly start to polish the crack/seam out, test and sand till it goes away, if it is a casting flaw and been there this long, I doubt it will cause you any trouble and not likely to crack unless you hit it with a sledge hammer. Also they have new welding rods made especially for welding cast Iron that work great.
Click to expand...

Hey, hondo... I was DNT with a steel tubing mfgr in PA (2nd generation, actually), ultrasonic test techniques were designed/developed in my living room when I was a kid, they were used to test the tubing wot went to a certain boatyard in Connecticut. /bcforum/images/%%GRAEMLIN_URL%%/smirk.gif
 
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