Crack in cylinder wall, Now with new pics

[63comet]

When re-doing my 250, I noticed what appears to be cracks in the bottom of 5 and 6 cylinder. These look like they have been there since casting of the block. I can't see the cracks in the cylinder itself, and I can't tell how far up the wall they go. This particular motor ran good until it started eating distributor gears. My question is will they be a problem. The block is 46 years old.

 

[Bort62]

Let's see a picture.

 

[63comet]

Here is an attempt to post pics.
http://i141.photobucket.com/albums/r54/ ... crack2.jpg
http://i141.photobucket.com/albums/r54/ ... /crack.jpg
http://i141.photobucket.com/albums/r54/ ... 140004.jpg
http://i141.photobucket.com/albums/r54/ ... 140003.jpg
Also a few pics of the BB 200 that looks like it might have to go in.

http://i141.photobucket.com/albums/r54/ ... 140001.jpg
http://i141.photobucket.com/albums/r54/ ... 140002.jpg

 

[simon]

looks more like a shrink hole to me.

considering the block has lasted more than three decades, on a non-performance application it might as well last another three decades.
magnafluxing, however, is cheap precaution before you dump a couple of benjamins into the block.

And even if this casting flaw turns out to be a crack, it could be fixed, probably.

 

[63comet]

I pulled the cam out of it and I will get more pics tommorrow, But they are definetely cracks as you will see if I can get better pics. The only thing is that it ran just fine with no problems at all, I just happened to notice the cracks when I was going over the block with a fine tooth comb. It already has everything done to it, (bored, decked) It ran fine with no signs of any problems.

 

[rbohm]

8) those cracks dont seem to be too deep, and are in a location that shouldnt cause any problems. i also doubt they will propgate any further. i would like to see the cylinder walls though before i commit to any real recomendations.

 

[Bort62]

I would say as long as they do not run up into the cylinder, they should be fine.

That is a low stress area.

 

[63comet]

I've added a few pics that show the cracks much better, I just do not understand how it ran so well with absolutely no problems at all.

 

[Bort62]

Yeah, If I were you I wouldnt Gamble...

200 blocks are cheap and easy to come by.

 

[Stubby]

It looks like a casting line or flaw. I dont know for sure that it's a crack.
If it's not too much trouble, take it to the local machine shop and get a second opinion.

 

[falcon60]

It looks like a casting line or flaw. I dont know for sure that it's a crack.
If it's not too much trouble, take it to the local machine shop and get a second opinion.

I think so too. It has the look of a casting line rather than a crack. The contour of the area in question mirrors that of the shape of another obvious casting mold line in one of the pics. I'd spray the area down with carb cleaner and dry it with air. If the area then stays dry it's not a crack....a crack will wick oil back to the surface and spread out on both sides. My money says it's good.

Terry