Block rust/dirty/factory coating? Can't get off.

[CanadianTalonTC]

Hey guys.

Basically I got my block all machined/cleaned etc but there is some sort of thickish black coating on it that was on my block before I took it in and apparently the machine shop cleaning it couldn't get it off. A coarse wire wheel won't touch it. The only thing I've managed to do is chip it off a bit where the corners are cracking near the block.

Is this from the factory? It's super durable but its uneven and looks crappy. I managed to remove the bit of rust off the block but that's it.

What would you guys do? Clean up the edges where it's chipped away and just paint over the rest after scuffing with the wheel? It's very well adhered to the block besides a couple corners.

Joel

 

[BogusSVO]

Inside, by the main webbing.

Some blocks do have some sort of coating in that area.

 

[ambush91]

My block in my 97 GSX had that coating as well. My block was rusting some and the coating was flaking away down in the corners. I picked away all that would come off and cleaned up my block as best I could with a wire wheel on the drill and used some wire brushes and picks to make sure I cleaned up all the coating that was gonna chip away Then just painted over the block with about 6 coats of high temp black paint off the shelf. It doesn't look perfect but the only time the block will be seen is when I'm under it doing oil changes so It doesn't need to look as good as say a Valve cover which will be seen anytime you pop the hood. I gave the block in my old 95 gst the same treatment but the coating on it seemed more paint like and came off with a wire wheel no problem. One thing to note though is the block in my GSX was rebuild by Mitsubishi in 2012 so they may have used a different coating on it where ever mitsu does their block work.