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Cylinder needed milled, compression question

Discussion in 'Engine/Tuning' started by DEADLY FORCE, Feb 22, 2014.

  1. DEADLY FORCE

    DEADLY FORCE . Established Member

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    image_zpsc89136b8.jpg image_zps7ec739b7.jpg

    Kind of an advanced question, I bought some used Aluminator coyote cylinder heads and were boxed poorly when shipped and had some scratches on the gasket surface so I had a machine shop plane/mill it down -0.1 mm which equals to 0.004 inches. Does anyone roughly know how much of an increase in compression this would be if I used a stock head gasket? Thanks in advance.:rolling:
     
  2. grnenvy

    grnenvy New Member Established Member

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    Only 4 thousands it's not much. U can buy the multi-layered head gaskets in different thicknesses so your ok.
     
  3. 03Sssnake

    03Sssnake TK-421 Established Member Beer Money Bros.

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    Doubtful that .004 thousands would result in much of a compression bump. The machine shop probably took off the minimum amount of material needed to true the heads.

    However I am only getting back into the Ford side of things these days, so I am not sure with these castings. With my 243 GM castings, roughly every .0065 off = -1cc from the combustion chamber. I took .020 off to get to 11:1 up from 10.5:1. That was with GM MLS head gaskets being used.
     
  4. hopony

    hopony New Member Established Member

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    3.14× bore radius in mm squared × .01 = volume of area removed. You can use cr calculator online and change head gasket thinkness by .1 mm it looks to be about .09 increase in compression. If I entered everything correctly.
     
  5. DEADLY FORCE

    DEADLY FORCE . Established Member

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    Cool, thanks for the information guys!
     
  6. DEADLY FORCE

    DEADLY FORCE . Established Member

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    I'll be at around 10.1 to 1 then with my new build.
     

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