Small defect in cylinder wall, getting opinions

[tech71]

1 hour ago, Preyupy said:

The options are 1) assemble it as is and see if it smokes.

It wont, not from the defects pictured anyway.

[jimk]

1 hour ago, tech71 said:

It wont, not from the defects pictured anyway.

What about blow by?

 

I predict it would always be looser because someone pulled the head before draining the block then left the engine sit.  Now it has the pits.

 

I tried salvaging a long block that I bought for a builder engine.  After pulling the pistons it had pits.  Tried boring to 2nd over.  Here is how it ended.  Junked the block.

Edited July 25, 2023 by jimk

[Son of Marty]

59 minutes ago, jimk said:

someone pulled the head before draining the block then left the engine sit.  Now it has the pits.

This is your best case,  if it was a contaminate in the casting what else might be lurking under a thin film of metal. By chance is it a late 73 or early 74 block?

 

PS, I would have a hard time going back to a machinist who didn't mention that flaw when you picked it up.

Edited July 25, 2023 by Son of Marty

[cmsanford88]

Thanks for the additional input guys. I'm taking the block to the machinist this week, will discuss sleeving etc. Agree that they should have brought it to my attention before I left with the parts, will see how they respond. In general I've had good experiences with them tho. 

 

With a few nights sleep I'm leaning towards rolling the dice and building it, will get it inspected and go from there tho. 

[cmsanford88]

Also, thinking back on it the block came out of a running car with low compression. It sat in my finished basement for a few months but I definitely don't remember meaningful surface rust on the cylinder walls. Would point to cavities in the casting then. I'll have to check the date stamp when I'm home. 

[cmsanford88]

Chatted with my machinist today. Long story short, they said they'd just run the block as-is. They re-honed that cylinder and checked the depth of the marks for me, ended up being about half a thou for the larger of the two. Not perfect, but it's such a small blemish on an otherwise good block they advised it wasn't worth the money to get it 100%. Photos of the clean cylinder below. 

 

 

[cmsanford88]

Hey guys, reviving this old thread for an update. Finally got the time to get the engine totally together and did a 20-minute bench test this weekend. Compression numbers all look good after the test and no blow-by or other issues. We’ll see how it holds up, but for now I’m very relieved that the block seems solid.