how much can you safely plain off the head of a 1.5 litre 12 valve motor ( out of an 86 NON cvcc carburated crx. also, is there a formula to calculate how much your compression is raised in relation to how much you plain off or does anyone know how much it is raised for every 1000 you take off.

 

I want to know the same thing, I have a D16

although i've heard 1mm or .039in will rasie your 9.2:1 (if its a dx) to almost 9.3:1
but I think the most you can do is .040in but not sure, does anyone know for sure?

 

why dont you just use a thinner head gasket?