well, im doing a b20 non vtec build. im getting pistons but they are only going to make the compr 11:1. i want to be as closets to 11.7:1 as i can. i know i will not be able to mill to get that high but how do i measure to find out how much i can mill it?

 

Actually you can bump the compression ratio a lot by milling a little off the head.To get an accurate number you will need to measure everything.The deck height needs to be measured as well as the combustion chamber.With a .030 deck height and a 45cc head you will need to mill about .020" off (about 3cc).But with aftermarket rods and pistons your deck height maybe closer to .010-.015.Then you would only need to mill .005-.010" off.To get accurate results you need accurate measurements.
Glenn

 

Milling for compression can be a really bad idea.

You must have adjustable cam gears to compensate for the closer ratios.

 

Just go with a 1layer headgakset you give you more compression, rather than physically removing material from the head.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GarageTech &raquo;</TD></TR><TR><TD CLASS="quote">Just go with a 1layer headgakset you give you more compression, rather than physically removing material from the head.</TD></TR></TABLE>

is that a good idea for a 1 layer head gasket?