Can't see 'flash' existing there though. And if there was flash there, why set it up on a lathe or milling machine to machine off flash instead of a quick filing or mini grinding it off? You're not looking at machining a 'fit' between two parts here.
Flash would be the wrong word... When cracks in the mold surface happen due to age . They have to grind in "draft" or else the casting won't come out of the mold. You can see the disc grinder marks left in the mold in the first picture. ( below the said "machined part")
They only get somewhere between 180,000 -200,000 castings from a mold before it's done and when I was building those molds in the late 80's early 90's the mold was 1.2 million a pop.So scarpping a casting is a last resort.
They are already " in there" machining for the pump and block mating surface, so a quick change to the machining process to make sure the ring gear clears is no biggie?
Again though.... this is just a guess?
