MLS (Cometic) Head gasket and Roughness Average - Discuss
#1
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With my Cometic head gasket slated to arrive on Tuesday I'd like to get the block and head surfaces as smooth as possible but how smooth is "smooth". Cometic head gaskets require a RA50 or smoother whatever that means.
My head is smooth enough that I cannot feel anything with my fingers or my fingernail when I run it across the surface. However, my block deck has machining marks. When I run my fingernail across it I can feel it "zip" across the machining marks. This cant be good and i'm not looking forward to sanding it down with the block already assembled in the car.
Thoughts?
My head is smooth enough that I cannot feel anything with my fingers or my fingernail when I run it across the surface. However, my block deck has machining marks. When I run my fingernail across it I can feel it "zip" across the machining marks. This cant be good and i'm not looking forward to sanding it down with the block already assembled in the car.
Thoughts?
#5
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How the **** is he supposed to tape holes and sand it?
Anton, try a machinist's stone, one of these:
![](http://images1.mcmaster.com/Contents/gfx/small/4474ap1s.png?ver=25957757)
It's a sharpening stone, part number 4474A4, if the imagine doesn't work, I can't seem to find it anywhere else.
Put a few drops of oil on the block, and just hone it like you'd wax your hood, smallish, fast circles. Then just wipe it down a million times, until your cloth comes off clean. This'll help maintain the block's flat surface much better than sand paper would.
Anton, try a machinist's stone, one of these:
![](http://images1.mcmaster.com/Contents/gfx/small/4474ap1s.png?ver=25957757)
It's a sharpening stone, part number 4474A4, if the imagine doesn't work, I can't seem to find it anywhere else.
Put a few drops of oil on the block, and just hone it like you'd wax your hood, smallish, fast circles. Then just wipe it down a million times, until your cloth comes off clean. This'll help maintain the block's flat surface much better than sand paper would.
#7
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This is exactly what i was hoping to hear. People can tell me that I need to polish my block deck and head all day long but as long as people have gotten by just fine without doing that then i'm not going to worry about it. I'll definitely spray the gasket with the copper stuff.
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