Common block flaws?

[mongo]

I went over to a buddy's house last night to borrow his starter jig for my 3.4 so I can move my starter to the correct (FWD) side of the block. While chatting about his 3.4 build he did, he mentioned that he had purchased 3 blocks before he found a good one. According to him, the first two blocks he bought had lateral cracks in the middle cylinder walls about an inch down from the top. The cracks were only found when the the blocks were checked with dye.

Has anyone else ever heard of this? Is this a common problem? There was no indication my block had any problems when I took it apart (rust in the cylinders, machinists didn't see anything, ect) but I am still thinking about buying a dye kit to check mine....

[geoffinbc]

You can use Mag Particle or Dye Penetrant to test for cracks. As for the cracks, no they are not common. I have a badly abused 2.8L in my garage that was overheated, because of low coolant. The heads were cracked between every valve seat but the block is fine.

Just FYI a lot of people can seriously mis read Dye Penetrant tests. So if you do it yourself read up on it and do more than one test if you think you see something. Another method is to let the Developer sit on the surface for about a minute and then wipe it off. Apply more developer and wait for any results. Wiping off the developer after applying it removes any dye sitting in surface grooves but dye that is in actual cracks will still be there and will bleed into the developer.

A machine shop might have the ability to Mag Particle your block which is much quicker and will even detect flaws slightly below the surface.

[mongo]

Since I had never heard of this problem with the blocks before, I beleive this is not a block flaw or even overheating damage. I think he bought blocks from a junkyard that left the water jackets full and let them freeze.... possibly with water inside the cylinder...

[robertisaar]

junkyard that left the water jackets full and let them freeze.... possibly with water inside the cylinder...

WINNER!

#1 reason for cracks in a block regardless if its a iron-block 4-cylinder or an aluminum v12, water freezing inside the jackets WILL cause cracking.

[01GPGT]

thats what killed the first engine in the 82 GP i had put water in the block when i went racing (local strip will through you out if you have anti-freeze) that night it went down to 20*