i have a 91 crx dx with the everything stock. i am planning on doing the mpfi swap so i picked up everything needed for that as well as a extra si head with everything on it. now i got the head milled .040" and i understand that i have to retard the timing by about 4 degrees, from doing my research i believe its 1 degree; .012"milled. now here is my question, if i put a a6 cam which from what ive read retards the timing by 4.75 degrees(correct me if im wrong), how much do i need to retard my cam timing to avoid detonation. ive looked at a compression calculator and i should be at 10.19:1. thank you for any help

 

on a SOHC D-series engine, milling the head 0.040" will only change the cam timing by slightly over 1 degree (1.0132*)

 

Anybody else?

 

What do you want to know? The the math and answer was already given to you by "jlicrx". The camshaft grind is probably off that much... If you are that worried about it get an adjustable cam gear so you can advance it and put it back to factory.

If you want to read on exactly how he got the answer then look at this...

http://hondaswap.com/attachments/471...camdegrees.pdf

Your camshaft will already be retarded from the milling... and you don't have enough compression to worry about detonation. A Honda engine is efficient enough to run 10:1 on 87... unless you have super crappy gas then try it and listen for detonation... If you have some then go from there.

 

I love learning new things! Thanks for the post N3va3vasatisfied!!!