decking heads for more hp

[14.5 drift]

Well I am taking the car in to have the timing belt done, and i was thinking of having my head sent out to be milled. Ideally I would like to have a 9.0/1 compression for better response and more hp on less boost. My goals are not for huge hp so the higher cr should be fine for my goals, not sure though.

How much should the block be milled to attain a 9.0 cr, and will I have to worry about the pistons throwing a party with my valves.

Is this a reliable way to make more hp, or is it a completely hair brained idea that should be left alone?

Thanks for your feedback dsm wisemen :bowsdown:

 

[bigjangin]

Why spend money on removing material from the head when there are much easier ways to make power and improve drivablility. I dont know if you could get all the way to 9:1 by removing material, but why would you? In the event you need to get headwork(say you blow a hg and the head gets warped) done later on, if the head is warped you might have to trash it because too much material has been removed. Not to mention the cost. Sounds like you are paying for the work to be done, that means you will pay to have someone remove the head, pay the machine shop to remove the valves, replace valve stem seals(if you have lots of miles), deck the head and put it back together.

Plus if you want to run more boost later on, you'll have higher compression which will induce more knock. Just stick with more basic mods to gain power. Once you have all the basic stuff done(turbo, fmic, fuel and tuning) you could build up your engine, and if you wanted more compression you could do it the right way with aftermarket pistons.


Another thing is if you decked the head to much you would have to check the valve to piston clearance. If you removed enough to make the cr 9:1 the valves might hit the pistons.

 

[gixrman]

If you want better respounce put a 1g TB on it. You will have to mill out the intake manifold but its a lot cheaper than having the head milled.

 

[Tallen]

PORT the intake manifold.

There is barely enough room on the head stock, you can't take off hardly anything. Thats why they sell thicker headgaskets (for one reason anyway). That Mr Valve does not say helo to Mr Piston.

 

[kpt4321]

There was a spot about this a couple months ago where I did the calculations to see how much material would need to be removed. I don't remember what the exact numbers were, but it was way too much.

Not to mention, this is NEVER the way to higher compression. You want higher compression, get the right pistons.

Decking the head will throw off all kinds of stuff that matters, like cam timing.

 

[Defiant]

Yeh.

But you "deck" blocks, you shave heads.

 

[pinknuggit]

no, you surface heads, and deck blocks. at least that's the terminology all of the rednecks use at work.

when i rebuild my head, it was warped pretty bad. I had to take .008" off of the surface in two steps just to get rid of the warp. I tried .005", then .008", and on the second step, i didn't level the head right, so i had to take it down to .011" to true up the surface.

I had the seats cut to fit my 1mm oversize valves, and if the head was surfaced just a tiny bit more, the valves would be sticking out. Good thing i caught it being unlevel before i took .015" off of the head!!

 

[ItsStockOfficer]

no, you surface heads, and deck blocks. at least that's the terminology all of the rednecks use at work.

when i rebuild my head, it was warped pretty bad. I had to take .008" off of the surface in two steps just to get rid of the warp. I tried .005", then .008", and on the second step, i didn't level the head right, so i had to take it down to .011" to true up the surface.

I had the seats cut to fit my 1mm oversize valves, and if the head was surfaced just a tiny bit more, the valves would be sticking out. Good thing i caught it being unlevel before i took .015" off of the head!!

You don't "surface" off enough material to raise compression! You MILL it! Sheesh! Thats like getting honing and boring confused for cylinders!

 

[pinknuggit]

hey i said that's just what the rednecks at work call it.

the machine we use is called "surfacing machine", as it says on the machine itself. so