ok how much is good to take off when one mills the head. I will also be running a higher compression head gasket, and already pretty high compression, type s. So what the deal, how much should I take off.
How much gain will I be looking at with milled head, and head gakset? arounf 7hp?
What CR do you want to run? Type S and the head gasket should put you around 11:1 or more depending. I would mill any other than necessary for a good seal unless you are wanting to do some serious tuning on 93 octane or higher.
Keeping the factory headgasket (or at least one with essentially the same thickness) and going with Type-S pistons, I believe taking .035" off the head would yield you somewhere between 10.8 and 10.9 compression ratio. All assuming that there's enough piston to deck clearance, this would be the machine to spec that I'd recommend. Of course I could be wrong.
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Josh's '92 Milano Si (5spd)- The mod list is growing!!
If you have a target compression ratio you will need to get the headwork done first. Then cc the head and take measurements on the block to get your base numbers. There is a formula floating around here somewhere, but you will likely need to adjust it for your application. Basically, once the head work is done you can get all the measurements & figure out what compression you are at. then you work backwards to figure out how much material to mill off to get the compression you want.
Also, with the stuff you are doing you may want to clay the head to determine the max you can mill off before you run into clearance issues.
If I can find my notebook that I have all of my measurements & calculations in I'll post up all the stuff I have.
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That's one bad mother - shut your mouth - ... i'm just talkin bout my lude
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Is any of this info. in this post the formula you're referring to? ^^
This (vv) was posted by 71dsp:
I think you've skewed the math a bit. Here's what you need to do, and unfortunately, I don't have all the data you need.
You know that compression ratio = volume of air in cylinder at BDC/volume of air in cylinder at TDC : 1.
So, what we need is the bore and stroke of the engine, headgasket thickness, piston to deck clearance, combustion chamber volume, and piston dome volume (use a negative number for a piston dish).
The air in the cylinder at BDC is [(bore/2)^2 * 3.14159 * (stroke + headgasket thickness + piston to deck clearance)] + combustion chamber volume - piston dome volume.
The air in the cylinder at TDC is [(bore/2)^2 * 3.14159 * (headgasket thickness + piston to deck clearance)] + combustion chamber volume - piston dome volume.
2157 / 4 does NOT work because 2157 / 4 is just (bore/2)^2 * stroke * 3.14159. Using that number neglects the head gasket thickness, piston to deck clearance, and the combustion chamber volume.
The piece of data I don't have is the piston dome volume. We can back into it though because I do know:
bore: 8.7cm
stroke: 9.07cm
headgasket thickness: 0.030" (typically) i.e. 0.762mm
piston to deck clerance: .020" (typically) i.e. 0.508mm
combustion chamber volume: 53.8cc
Using my little Excel spreadsheet, I get that the piston dome volume must be about +1.5cc to yield a 10.01:1 compression ratio using the above data.
Now, let's say you're going to mill 0.035" off your head. That's like effectively having a 0.000" headgasket thickness, and a 0.015" piston to deck clearance. Again using the data above with these two changes and a 1.5cc piston dome volume yields a CR of 10.88:1. Not quite 11:1, but very close.
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Josh's '92 Milano Si (5spd)- The mod list is growing!!
type s pistons are rated at 11.1 compression already, .5 for the head gasket, then probably .3 for the mill job, thats right arounf 11.7 compression. It still doesent seem high enough for me.
In other words, you'd have to get a head gasket that is 0.021" thinner than the stock one to raise the CR by a half point. There's no way a thinner head gasket is that much thinner. The aftermarket head gasket would be less than 10 thousandths thick! I'd think that perhaps you'd raise the CR by at most 0.25, but probably closer to 0.2.
I just don't understand the cost of a thinner head gasket to raise the CR by 0.2. Remember that a head gasket is a one-use only item. Once it's installed, you throw it away if you ever remove the head.
How much was milled off the head? For 0.3, you'd have to mill off 13 thousandths with a stock head gasket.
im getting sick of h22 motors not having the support and power that b series has. I meen come 1000 dollars to sleeve a block only when your going na, its lame. This is wh people have b serious motors, there sooooo much more responsive to mods, and 1/2 as cheap to keep up. Im not dissing on the lude, it just really makes me mad. Sorry is this is off topic of the subject but its been a really long stressfull week, just looking to blow some stream, so far it hasent succeded. I need a girl!
I don't know where you've looked at for pricing, but all of the sleeving I've seen run about the same price for H series or B series engines. The cheapest full replacement sleeves I've seen are GE, which run about $850, whether it's a B series of H series engine. Other sleeves (AEBS, Darton MID, etc), run well over $1k
for the sleeves and installation.
There are a lot of well built B series engines putting out a lot of power, but I have yet to see someone put together a really well built H series engine.
Also, how is a B series 1/2 the cost to maintain than an H series engine?
about the sleeving, I am saying on the b series you dont have to sleeve to put forged pistons in, you do so with the H. I say its 1/2 the cost to to the abudent aftermarket parts available for them. For example, intake manifold, there are no good ones out for the H motors, there are about 10 out for b series. The only one I know of that actaully benifits NA is the euro r and its twice as much money to make fit a usdm motor, then as you were to go buy a dc2r IM and put it on a b18c1. But this is what keeps alot of people away from the h motors, and in a way this is a good thing. But back to the topic, its a drag that you spend that much money for little to no power gains to the motor, respectably.
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