if i milled .046 off my cyl head surface on my B18A1, how different is the compression now? how would i check it, if there is a method to check?

 

google honda compression calculator...there like 3 or 4 out there

 

.20 is roughly 1 point in an 81.5mm bore .046 is alot, i would be very concerned about p to v clearance. i wouldnt advise taken that much material off. your gonna run into ptov clearance issue as well as timing issues and its gonna be hard to find a cam gear with enough adjustability to compensate for the extreme change in deck height

 

piston to deck height
-0.033 (Meaning that your piston would stick that far out of the block)

If you add the thickness of the head gasket
0.026

you are left with
0.013 clearance

Compression ratio
10.7:1

 

you'll want to degree the cams with that much off. the marks aren't going to be accurate anymore.

 

He can't take that much off unless he plans on running a thick head gasket. Ideally you want to have around .030 between your piston and your head to help dissipate heat and lower the risk of detonation.

 

thicker head gasket would be the easiest way to compensate for material lost

 

http://www.zealautowerks.com/bseries.html enter everything from your setup, and in the head milling and block decking section put your .046