Explain Milling the head - Honda Prelude Forum

Crate · 02-12-2003, 10:16 PM

Could someone please give me some insight as to what exactly "milling" the head is. im curious.

soudn to me like its just port matching or "milling" down all the edges in the head?

thanks,
Creighton

yes i tried searching.

red92si · 02-12-2003, 10:35 PM

milling is when you cut down the entire surface of the head that comes in conact with the block. It is used to make sure there are even surface's to maintain a good headgasket seal. It also is beneficial in tuning because you can mill down the head to bring the combustion chamber down closer to the cylinder. This increases compression, but also has one disadvantage... if you mill too much, there is a chance that your valves will come in contact with the top of the piston.

Hope I helped...

PS

ne other thing to remember is that milling may cause your timing belt to fit looser.

Crate · 02-12-2003, 10:39 PM

hmmm. reason for asking is a dyno plot i saw in another thread thats up here.

JDM H22. i/h/e/milled head dynoed at 190.8whp.

ok. hmm i don't plan on going too wild with this motor. (like turbo anytime soon or anything) would raising the compression due to milling the head put any extra strain on the stock piston land rings? being as they are weak from previous readings.

right now, my setup will be i/h/e/pullies/vafc and some dyno time to tune very soon.

thoughts?

thanks!
crate

19924ws · 02-12-2003, 11:27 PM

Milling also, by bringing the head closer to the block creates slack in the timing belt bec the head sits lower. This is not usually a prob, but it can be.
Any time you inc your hp at all there is more stress, so yes raising comp will do it. Mike

Crate · 02-12-2003, 11:42 PM

would milling the head in a since be the same thing as running type s pistons?

*edit* nm. read some info on the pistons. that' dbe a waste for me. i got 10.6:1 CR already. might look into a headgasket. to raise it a few points after i get my ignition done.

cuseC08 · 03-05-2003, 04:58 PM

if you mill ur head becarefull with highlift cams cuz you'll hit a valve into a piston. H series motors don't have much valve to piston clearance. Best bet is to just get high comp. pistons and high lift cams. then ur set with hp

JC_lude · 03-06-2003, 08:51 AM

??? milling head is it cut down the head to make it closer to the piston ? or is it mean fill up cylinder head with alum near by the valves?

19924ws · 03-06-2003, 09:27 AM

Milling is shaving metal off the head which reduces the size of the combustion chamber.
Filling the cylinder head with metal is called "welding the chambers"
My head is both milled and welded, it's a nice combo. Mike
Here are some pics of my car and the JG Redline Series head, cams, and cam gears. Hope it works.
http://www.imagestation.com/album/?id=4290715273