Has any ever seen a hole right here??

[clarkb]

Just wondering if any one has ever seen a hole in a block on the exhaust cavity like this? This is at the #2 cylinder. He had low compression (100psi) so he pulled the heads off to take a look. Thats when he noticed this hole. Looks like something came from the inside out.

Had to edit in another pic. There is two holes down by #5 cylinder too.

Any thoughts?

[johnnyracer]

Yep . But they usually line up with where the bolts thread into the block in that area. Do they leak ?

[Capt.Insane-o]

Just about like every other Merc production block. Nothing unusual.

[clarkb]

Yep . But they usually line up with where the bolts thread into the block in that area. Do they leak ?

Ive only been able to see pics so far. Plan on going to look at it this evening. He says the holes go all the way through but there was no evidence of anything leaking(soot trails or hot spots on the heads). If there is a hole all the way through, it would have to leak, right? What would cause it to do that? I've only built a few of these motors and never seen anything like that. But then again, I learn something new everyday about them too. Im just trying to figure out what causes it. Thanks for any responses and advice.

[flabum1017]

air pockets in the casting............. very porous

[outasite]

Usually the holes are at the bottom of bolt holes for the rear exhaust cover,they won't leak and cause no problem.Very common!

[kingsbiship]

Is it possible someone enlarged the water holes in the exhaust cavity, and came thru the side? That is where they would land.. isn't it?