Hi all,

first post here. Bought this BP4W head used from a fellow member and after soda blasting it and cleaning it (it was filthy) I noticed this on cylinder 1. It looks like tiny little dents (maybe a few thou deep) and then groove on the edge. The worst area of the groove is about 1mm deep. The last picture shows Cyl 1 vs 2 (cyl. 1 is the only one with damage)

the previous owner was boosted and said he never had any issues (taking this with a grain of salt) but any idea what could have caused this?

Is this head salvageable or do I have a $400 paperweight? I was planning on using this head for a built bottom end and turbo build.

 

I'd smooth that out with a dremel and call it good. The fire ring where it seals is visible in the picture, and far enough away.

When I port a miata head, I remove that metal around there anyway to unshroud the valves.

 

Needs to be surfaced. Bring it to a qualified machine shop and have it inspected to make sure it is a good core.