Casting flaw? Or wtf?
 

I bought a complete 2000 1.8 in MD a few years back from a garage that said "it was pulled cause bad head gasket." I took this thing apart over the past few weeks, but Sunday I finally pulled the pistons and rods out of the block so I could hone it. Right next to the #4 cylinder oil squirter, I saw this. Is this a casting flaw? I didn't find any pieces in the oil pan, and there is absolutely no damage to any internal parts such as crank or rods...so if it is something that did break off, where did it go?
I leaned the engine block back on an angle and filled the water pump port up with water until the level was flush with the top of the block...nothing leaked out. I am just a bit concerned, as I've never seen anything like this before.
Attachment 137757

didnt we JUST have this thread? oil return drain... normal

cause :ne: because

edit: found the other thread on pg2
https://www.miataturbo.net/engine-pe...-caused-83582/

Incredible! Thanks for the info and link.

Is this going to be the new MT monthly thread?

To be fair, it IS a big scary looking hole. (just like your mom)

Giggity

"Who is your mother?", Alex.

I would have been freaking out if I pulled apart my bottom end and saw that haha.

It's not like it's a cleanly machined area...it literally looks like there should've been a huge chunk in my oil pan. Definitely made me throw up a flag.

+1

They definitely could have done a much better job of making it look like it belonged there.

I wonder how many "puckers" that hole has caused over the years. :giggle:

I made it look better when I built my engine. It just takes a deburring bit and a half an hour (for that part) and several hours for the whole engine.

I had a similar experience the first time I got deeper into my BP6D head. The castings around the lifter bores have a finish similar to aluminium foil and looks to be full of scabs that can come loose at any time.
A very different finish than the external castings at least.

But you get used to it after a couple of engines...

Also the oil pan. One of those flaws I initially overlooked as a casting flaw that turned out to be a small crack.