After numerous overheats, MINI found my head was warped and machined it down .006" and are in the process of reinstalling. I have lots of concerns about the whole thing, but my question is how much will .006" change my compression ratio? Is it significant or in the noise?

 

i'm no pro but i'd say the effects if any would be way minor . you may want to run some sea foam now and then to keep deposits to a minimum . but seriously they wouldn't do it if it were gonna come back again . they probably happy to have you fixed .

 

the factory has a thicker gasket that will take up the difference but overall it won't change the compression much

 

You haven't met these bozos...

I suspected as much but not having seen the inside myself I couldn't be sure.

 

.006" should change a R53 compression ratio from 8.3 to 8.425.

More math on this thread if you're interested.
https://www.northamericanmotoring.co...d.php?t=127180

 

1.5%...thanks. I would say that's not significant.

 

Maybe you can get a new tune that will take advantage of the 1.5% increase.

 

That's funny