I've never heard of anyone developing a crack in an LT1 block before, but someone here locally told me that he's had a few develop cracks in the cylinder bores, letting coolant into the combustion chamber and crankcase. I've got my motor torn down because of a blown headgasket, and need to know how carefully I should check the cylinder bores out. I ran my finger around the bores, and nothing feels rough. Should I get a mirror so I can see the part of the bore that I can't see now(motor is still in car, can't get my head down in there to see all of the bore)?

Story is- Car ran hot because radiator clogged, a few months later intermittent white smoke showed up along with losing coolant. Drained oil and it looked like chocolate milk Machine shop says they see a blown spot in the headgasket, but I can't really see it. Just wondering how much I need to check the block out. I'm having the heads checked out at a machine shop.

 

Only time i've heard of it is when the block has been bored too thin. I haven't really ever heard of any blocks developing any sort of cracks in the cylinder bore unless there has been previous damage. If you just blew a head gasket, you shouldn't even worry about it honestly.
Mine has cracks in it, but those are from the piston making contact with what was left of the valve. Then after the piston was all in the oil pan, the rod tried to escape by making a window

-Shannon

 

Damn pistons, always trying to escape

 

My block cracked Never figured out why. I had my head gaskets blow a year before the block cracked... The crack was on the #7 cyclinder wall I believe. Originally they said i had a blown head gasket but upon furhter inspection they found it was the block

 

Toby, any more details on what happened before the crack? Overheating? If so how much. Also how was the crack on the bore, longways or side to side?

 

Toby's is the first case I have heard of outside of those caused by severe mechanical failure. I know one of the Impala guys had the RAMIT intake, you know the one that picks up air in the airdam, well he picked up water in a big way, believe he said all pistons and the block were cracked, at that point I think they stopped looking for anything good leftover.

 

mine cracked.. Wasnt pretty either.. Im thinking it was due to water in the block over the winter..Not really sure..the oil pressure hit zero, engine seized and when I went to rebuild it...I found this crack (pic is a lil blurry)

This is just above the casting number (327 is upside down..so its just above the 'bottom' of it)
http://12.217.21.69/engine/IMAG0347.JPG

 

Thanks guys. Anyone else?