I have an extra LS head i've been porting, as soon as i finnish porting/polishing it, i'm taking it to the shop to get the 3 angle valve job done..

here's my dilema.. i've been thinking of having the head shaved .030 to increase my Compression ratio..

in doing this, i shorten the distance from the cams to the crank. which in turn affects the timing.

I have AEM adj cam gears, and i know i can make adjustment for the shortened distance.. but i'm really not sure how much i should adjust..

i dont have access to a dyno right now (we have one here at the college but its the old analog style with dials and guages and no way to tie down the car )

anyway, should i just leave the head surface alone? (its fine right now) or should i resurface it and mess with the ajustment of my gears to get my timing right?

has anyone dealt with this and can give me some help with how many degrees to adjust for the shortened distance?

edit: i have JG cams and crower dual valve springs with titanium retainers to complete my modded head

thanks in advance


[Modified by Speedz, 7:02 PM 4/8/2002]

 

I don't think that just milling a head will change your cam timing. Event though you do change the cam to crank distance, the tensioner will take up the slack and the number of teeth in (which is what determines timing not length) between crank and cam will remain the same.

 

Milling the head WILL change cam timing.
The tensioner does only one thing, tensions the belt.
Milling the head .030" will probably retard the cams about 2-3 degrees so advancing
both cams by about that much should get you somewhat close

 

the obvious is that it should be checked on a dyno....mine (b16a head) is milled .030 and 2-3 deg. of intake cam timing added did not seem to help, esp. in pre-vtec acceleration.....so will wait for dyno.

 

hey thanks for the replies.. i'll see how it works, then adjust them both.. see what that does.. and eventually i'll make it to the dyno.

 

Why mill a perfectly good head? Make more whp in other ways. You may need that .030 later because of an unexpected problem.

 

heh, well this is an extra head. i'm planning on keeping the one on my car " just in case"
it will cost me $30 to get it milled.. i'm a poor college student so anything that i can do for cheap is gonna get done.. i also have some b16a1 pistons. but i really dont feel like tearing into my bottom end right now.. gotta have the car to get around.