Ok, basiccally i need as much info as i can get on this.
Is it safe? well, how much is safe?
how much difference will it make i.e. .020 will make x.1 compression?
how much will i need to adjust timing for the milling.
ive heard its safe, but you have to adjust the timing belt for some reason
lil help, knowledge appreicated

 

well i already have that...i never acctually tested it, but its supposed to raise it like 2-4 tenths of a compresion. im looking to run near 12:1

 

I thought when you mill your head you adjust the timing on the dist.?

 

Once you mill the head....you can never put it back to normal. Maybe higher compression pistons?

 

with cam gears you can..........
just a matter of how much..not sure if theres a way to tell

 

This has been covered in old threads, but for every 0.012 the head is milled, it is 1 degree of retard on the cam gears.

There is a compression calculator here: http://www.c-speedracing.com/h...c.php You need to know a lot of info on the H22 though. I have my head milled 0.020 with 11:1 Type-S pistons and it figured my compression to be around 11.5:1.

 

that sucks, i guess ill just get the type 2 pistons then and not mill the head.
i wanted with the type s pistons to run a comp of around 12 but to do that id have to mill the head entirely too much to be safe i guess.
thanks

 

By that calculator, if you mill it 0.030 with Type-S pistons, you'll have 11.9:1. 0.030 is a pretty common mill. I wouldn't go too much over that, but I'v heard of guys going to almost 0.100.


When calcualting the compression for the milled head I took the volume of the combustion chamber and then recalculated it for the difference in height because of the mill. V = pi * r^2 * h I figured it was a more accurate way than just changing the head gasket thickness.

 

why not just take the center layer out and raise it that way,then if you want more mill it.for every 15 ths you take off a head retard the timing 2 1/2 to 3 degrees.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ranta18 &raquo;</TD></TR><TR><TD CLASS="quote"> I have my head milled 0.020 with 11:1 Type-S pistons and it figured my compression to be around 11.5:1.</TD></TR></TABLE>
that is the same amount that i milled my head w/ stock pistons, and this is exactly what i've heard...0.020 milled head = .5 raise in compression.

 

H22
Type S pistons (Std. Bore)
Mugen/Spoon Head Gasket
Milled .020

11.9:1

H22
Type S pistons (Std. Bore)
Mugen/Spoon Head Gasket
Welded Chambers
Milled .020

12.2:1



Modified by RS_H22 at 5:32 PM 11/6/2003

 

welded cumbustion chamber? whats up with that? any pics?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LudeHatchH22a &raquo;</TD></TR><TR><TD CLASS="quote">welded cumbustion chamber? whats up with that? any pics?</TD></TR></TABLE>

no pics, you just weld some of the areas shut in the combustion chamber... Top/Bottom edge, the sides between the intake and exhaust valves... Cloverleafing is a good example of chamber welding/reshaping... Alot of people reshape the combustion chamber into a clover leaf shape to minumize the cc count which raises compression and some say to increas air flow charactoristics...


Modified by RS_H22 at 5:54 PM 11/6/2003