Picked up an old B18A1 recently, tore it down, and was cleaning it when I found what appears to be a crack in the block, but not sure since I can't see anything on the opposite side. Can anyone with more experience tell me if this is cause for concern in this area (looking up from bottom of block) and/or if it's even worth taking to a machine shop for cleaning, honing, etc?

 

A couple more pics of the area in question...

 

usually I'd say that's pretty normal for cast aluminum blocks. But it appears a few small pieces have actually flaked away, revealing the crack to be a bit deeper which does concern me a little. I would bring it to a shop to have them run some tests, get a professional in-person opinion

 

Agreed. Don't guess or assume, have a machine shop do a penatrant dye check on the block before you spend any money on it. Crack checking should be a part of any shop's analysis before they agree to do any work on an engine (it really should be done during teardown), I'm not sure how common it is in reality though.

 

Have it pressure tested but I'm guessing some light cleaning/filling in that area would make it good as new again. Whether or not the price of that is worth keeping the block or just replacing it I don't know, like mentioned above you'll have to check with the shop.

 

looks normal

 

dye test will only show a crak if its not visibile.. that is clearly visible. you need to ultrasonic test it to see how deep it is.

 

If you can get another block easily, then take a die grinder to it very lightly to cut into the crack. Hopefully it's not very deep, you can cut out the "crack" and then hit it with a cartridge roll to sand it down smooth.

 

Just as the others have stated, at first glance it seems normal. However, when you take a second look, there seems to be flaking which is a sign of the block being compromised. It would be wise to get a second opinion of a professional.

 

There's cracks all over, is that normal? I've never seen anything like that in any of my blocks.

 

Make no assumptions, have it tested. Do not try to fill the crack or make any modifications. Let the machine shop do its work, its a simple yes or no. Its a pain to put so much time, effort, money into engine building only to have a major component fail after assembly.

 

looks to me like that casting flaw is directly under the metal on the outside of the block. Does the other side even go into the water jacket? If it doesn't, your golden. That would be a very rare place for a leak.

 

Update: I had the machine shop take a look and they concurred that it wasn't a problem, so I'm proceeding as planned with build. Appreciate all the responses on this! Learning a little more every day.

 

That's great to hear. With the curve the crack is sitting on, I wasn't sure if it was a crack over top an oil channel or some other conduit.

Glad to know it's nothing of concern, best of luck with your build.

 

I'd still take a cartridge roll to it and sand it down. No sense in leaving in a stress riser when your block is already apart.