science 0 Posted February 14, 2013 All I can find is a minimum height of 139.5mm. I'm guessing beyond this it affects the timing? What is the standard head height? Quote Share this post Link to post Share on other sites
captainredeye 0 Posted February 14, 2013 I think you end up with the valves staying open all the time if there is to much material taken off which inturn means the valves can get smacked by the piston. That ported head I have has 140mm on it still . Quote Share this post Link to post Share on other sites
elnigel 0 Posted February 19, 2013 When you have a skim you normally put a thicker gasket in to keep the compression correct. There is usually a bit of the gasket showing that has one two or three holes punched in it. This tells you how thick the gasket is. More holes- thicker gasket- more has been skimmed off usually. Quote Share this post Link to post Share on other sites
science 0 Posted February 19, 2013 When you have a skim you normally put a thicker gasket in to keep the compression correct. There is usually a bit of the gasket showing that has one two or three holes punched in it. This tells you how thick the gasket is. More holes- thicker gasket- more has been skimmed off usually. On the Vr6, the combustion chamber is not in the head, so it won't change the compression ratio. I think the way to tell is to measure the head height but I don't have the original factory value, only the 139.5mm minimum. Quote Share this post Link to post Share on other sites
MarkFoster 0 Posted February 19, 2013 Hmmm, are you sure that's right? Stealth use a a head spacer to drop the compression when they're converting an engine to forced induction.... Quote Share this post Link to post Share on other sites
science 0 Posted February 20, 2013 The VR6 head is flat, so skimming it will not change the volume of the combustion chamber. Like a book on top of a pint glass, the thickness of the book will not change the volume in the glass. Changing the thickness of gaskets /spacers or skimming the block will change the volume and therefore the compression ratio. Quote Share this post Link to post Share on other sites
MarkFoster 0 Posted February 20, 2013 Gotcha, I'm with you now, of course the spacer affects the block rather than the head. Sorry, blond moment. Mark Quote Share this post Link to post Share on other sites
science 0 Posted February 20, 2013 Gotcha, I'm with you now, of course the spacer affects the block rather than the head. Sorry, blond moment. Mark I had the same moment before I took it all apart. It became obvious when I actually saw it. Quote Share this post Link to post Share on other sites
