This should be done at each end of the block on each side — or at all four corners. Pink says that it is not uncommon for a block to vary in deck register from corner to corner by as much as ...

One slightly oversize rod journal combined with an undersize big end of a rod can take a normal 0.0020-inch rod-bearing clearance down to under 0.001 inch, and that's guaranteed to fail.

It’s often not normal wear and tear that puts a rod through a block, so being able to see straight through this Mazda 2.0-liter Skyactiv engine means bad things happened inside.