M52B28 Engine Issue

[Bingo369]

Just stripped my 96 M52B28 engine to give it a freshen up due to the oil light taking a while to go out when starting. The engine didn't burn any oil and a compression check on all cylinders had between 200-220 psi. When I removed the pistons I noticed black marks in the walls of the cylinders. I have given the cylinder walls a light hone but this hasn't removed the marks. Any ideas what these marks are? I believe the engine is a post-nikasil engine.



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[HairyScreech]

If that's not an iron liner block then you may have just killed it by giving it a hone!

[Bingo369]

If you see the first pic it's got the tag for a steel liner block !!! Any body any ideas ?

[Yasnick]

Looks like corrosion or pitting. We can clearly see the liners..

[Motorhole]

Looks like corrosion or pitting. We can clearly see the liners..

Yeah, if you can see the liners, it's steel liners. Nikasil was just a hard plating - I've got one of those blocks in my garage

Seconded - looks like water damage.