While changing the head gasket on my 98 Honda Civic with a D 16 Y7
I decided to try something new and stupid, and used oven degreaser.

I applied some to the engine block mating surface with a toothbrush, and then left and returned an hour later.

now the aluminum gasket surface has a dark “staining”

and I’ve noticed some pitting on the top of the pistons, honestly not sure if that was there before because there was carbon.
I’m afraid to proceed without advice.
i’ve considered just putting everything back together and trying to run the engine.

i’m also considering taking the block to the machine shop.

I have a really crappy engine block in storage that I may be able to salvage pistons out of.

Damaged piston


Salvage engine (maybe not)

 

The deck surface is not fully clean yet of carbon especially on the tops of the cylinders. Get yourself a brand new razor blade and lightly skim/scratch it clean and smooth. The pitting on the piston is kinda odd but not a huge concern, shouldn't really create hot spots and will most likely fill with carbon deposits fairly quick after running the engine.
You can use some copper coating spray (there is some made for headgaskets) on the head gasket applying a light mist coating on both sides to help seal any small imperfections for piece of mind. Just make sure to use a straight edge to check the mating surface flatness of the deck and head for any warpage or low areas before assembly.