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michael_antoi
10-10-2005, 09:10 PM
has anyone milled the head on their zc?

or any engine for that matter?

how much did u mill and how much hp did it gain?


still learning about this, so would this require aftermarket rods?

and should this not be done until i/h/e are done?

iamhappy46
11-10-2005, 01:46 AM
Depends on what you think milling the head is...
Porting & Polishing the intake & exhaust ports, requires removal of small amounts of metal to improve gas flow.
Shaving the head, involves taking a set amount off the base of the head where it bolts to the block and increases compression

michael_antoi
11-10-2005, 10:15 AM
well i was thinking about the latter...

i've done some reading on d-series.org

but was wondering if anyone here has done it?

Tony
11-10-2005, 01:13 PM
I have done that to my EG Si 5 years ago. I can't feel much difference at all.

michael_antoi
11-10-2005, 01:15 PM
ahh really?

how much did u take off?

Tony
11-10-2005, 01:27 PM
0.7mm

michael_antoi
11-10-2005, 01:33 PM
any dyno before and after?

didn't notice any gains at all?

how much did it cost to have it milled?

ProECU
11-10-2005, 01:58 PM
I have done that to my EG Si 5 years ago. I can't feel much difference at all.

I dont know your situation but thats probobaly because:

a) You didnt reset the cams via cam gears
b) You didn't retune the car now thats its running higher compression.

michael_antoi
11-10-2005, 02:04 PM
so in doing those two things, how much of a gain do u think there would be?

iamhappy46
12-10-2005, 08:44 PM
Of course, you could just fit a thinner metal head gasket fitted, which will have the same effect and is also REVERSABLE, if required.
Yes, there are gains in increasing your compression ratio. Depends on the ratio increase as to expected gains.

michael_antoi
12-10-2005, 08:47 PM
milling say .7 off the head wouldn't come close to the amount a headgasket would take off.

could always do both...

michael_antoi
12-10-2005, 08:49 PM
would milling and a thinner head gasket require a tune?

would there be any gains without a tune?

iamhappy46
12-10-2005, 08:59 PM
Doing both will more than likely result in your valves tapping the top of your pistons = engine rebuild. I would prefer the thin headgasket because being a metal type, they do not blow/leak/crack. For instance I have a .6mm headgasket on my Pulsar, factory is 1.2 or 1.6mm(not sure, caused I junked it)
The ignition advance would need to be modified and depending on what compression you end up with, a colder set of plugs and better ignition leads.

michael_antoi
12-10-2005, 09:05 PM
ahh ok i might have a go at the head gasket first then

how would decreasing the headgasket thickness by 1mm or so convert to hp?

iamhappy46
12-10-2005, 09:22 PM
Say increase your compression ratio from 9:1 to 10:1, should thereotically expect a 5 to 11% increase in TOTAL power. 100Hp stock to 111Hp

michael_antoi
29-10-2005, 08:27 PM
just taking my engine apart now before the swap


where can i go to get the my head milled...?

or what would i even look for in the yellow pages?