u/TheLastRole

Quick update from my previous post: first of all, thanks to everyone who commented last time. I followed some of your advice and used a grinding stone (400), making crossed and lubricated passes with no pressure.

I tested the flatness with a straight edge (DIN 874), and it's perfectly flat on all measured points (<0.04mm / 0,001 inches).

None of these marks catches a nail, and it feels kind of rough to the touch.

I'm also attaching a picture of the head gasket the car uses.

I'm still worried about the black zones and some of the marks around the Cylinder 1 edge.

What should I do next? Send it or keep lapping?

This is my first time doing something like this, and I don't want to mess it up …if I didn't already. Some context: iron block engine from my 4L 2.0 Porsche 924 79'.

I focused on the marked part, this first time, and wanted to check if I was doing well before moving forward. The process I'm following is:

1. Headgasket cleaner 10-15 mins, then a plastic blazer to remove the biggest parts
2. White Roloc, making fast passes without applying too much pressure
3. A little bit of gree scotch-britte on the hardest parts, again, no pressure, long passes, and some WD40.

Not sure how to deal now with the black spots remaining. The white roloc (120) doesn't seem to be able to remove them. Should I move to something harder? Should I use just a regular blazer?

I'm also a bit worried about the texture of the block. I can't feel those scratches with my fingernail, but the texture with the fingertip is kind of rough, which I think is kind of the point, but I'm not sure.

La organización retira el trabajo en la revista PNAS y reprocha que el científico y dos colegas no declararan que poseen parte de la compañía Vega Ocotargets para la explotación comercial de los resultados