To mill, or not to mill?

Integra Type-R Discussion - Discuss general ITR information, technical information (including requests for technical/mechanical help/assistance), modifications, tuning, etc.
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Dev
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To mill, or not to mill?

Post by Dev »

yeah that was cheesy, I know. I believe I read previously that the ITR head can be milled .030 for better compression. Anybody w/ pro's and con's on this subject???

recomendations for head gaskets, tips and to-do's while the head is off. With a stock bottom end and stock head (milled) what compression should I expect?

Any science appreciated!,

Dev
pUrExTc
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Post by pUrExTc »

personally, the only thing i would consider doing for higher compression, is the head gasket. Mugen sells one for pretty cheap (considering it's Mugen), however, my friend says it's kinda just like shaving down your stock one. Any advice on this?

P.S. The compression rate on this car is already unbelievably high!
'98 Acura Integra Type-R
'03 Honda CBR600RR
Surgeon General's Warning: It's OK to Smoke V8's
Dev
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Muegen Gasket

Post by Dev »

I have heard the same about a thinner HG. Technically, less gasket would equall more compression, but less gasket probably equalls piston to valve collision, I really don't know.

I guess its six of one...either milling or a thinner gasket......Muegen? is that a metal gasket.

Nice pUr, thanks. If you hear from your friend, drop me some science!
00civicsiturbo7psi
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Post by 00civicsiturbo7psi »

pUrExTc

so youre saying if you were to mess with the compression of the type r motor (10.6:1)

to only bump it up with a mugen headgasket which bumps it up to about 11.1:1 and risk the clearence.

not to say pull the motor and bump it to lets say 12.3:1 or 12.1:1 with say je pistons and build the whole motor, valve train ect....

the higher compression in an all motor car the more power it makes.

what in youre opionion is the best compression for a type r motor?

just want youre imput not trying to start no fights. thanks bill
Dev
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Gasket

Post by Dev »

Civic7psi, I think what is being said is that, for a little compression, the answer is go witha head gasket instead of milling the head down. Seems more reasonable......if you don't like what you build, take the gasket away instead of then replacing the head.

Yeah, open heart surgery on the B would be the balls, and would probably be the safest way to ensure piston/valve clearance, but for just a bit more compression and a lot lesss money, the head gasket may be the way to go.

Anybody else w/info TODA vs. Muegen gaskets?
00civicsiturbo7psi
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Post by 00civicsiturbo7psi »

dev


yeah i understand. the way i read it made me think he was implying stock compression is more than enough. well good luck
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Post by Bbasso »

If your going to open up the motor then do it right, Pistons, rods, w/ gasket.
But I would lean away from all that if you have low miles on the car or you are looking for reliability as a daily driver. In that case 2ply gasket would help bump it to 11.0-11.2 Just remeber that wich ever way you go "Tuning" is the key to get the best performance.
swed
Dev
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alright

Post by Dev »

Civic, Bbasso, pUr, wurd.
pUrExTc
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Post by pUrExTc »

ok...higher compression=more power and more maintenance. i was assuming this is for a daily driven car :? . anywho, i'm not one to mess around with my car that much, or worry about it on the freeways in stop and go traffic. but it seems that u all got my point anyway...
'98 Acura Integra Type-R
'03 Honda CBR600RR
Surgeon General's Warning: It's OK to Smoke V8's
Aj
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huh?

Post by Aj »

Well, first off, stock compression in an all motor car is not any where near enough, and the simple equation of compression = power, is just not enough of an explanation.

The reasoning behind bumping up your compression, is that it allows for the ussage of larger cams, giving the motor more power to push such a large cam profile, and to be totaly honest 11.1:1 really isn't cutting it if you really want to make any power. Compression by it self, does give you power, but not a sufficient amount to go tearing apart your motor for it.

To answer your question, I personally would stray away from milling your head, it permenantly sets off your timing, or at least to some degree and also moves the whole combustion chamber closer to the pistons. As far as valve to piston clearance with a head gasket, using the Mugen or Spoon ones you see out there will be no problem at all, you just need to adjust the timing accordingly, which goes for any time you change compression. Even after milling your head, you should have no clearance problems, just don't go more then like the thirty thousandths you mentioned, otherwise on pump gas, you'll be pinging all over the place. I'd go with a nice set of forged pistons, it allows you to run at higher tolerances with regards to tensile strength, heat, and detonation, where milling your head, you're still running on stock internals. Though, you wouldn't need to buy a new head if you mill it and wanted to go back, you could just buy a thicker head gasket, it's still a process that isn't easily taken back.

The bottom like is, that thirty thousandths you mill your head, is a good cheap way to put your compression up to about 11.8:1, and this way you don't have some of the problems commonly associated with thinner head gaskets, such as blowing out, and being less heat tolerant. Another thing, if you just want a thinner head gasket, just cut out the center of a stock one, it accoplishes the same thing, just be careful when installing it, as you need to remove the rivets to cut out the center.

lastly, higher compression does not = more maintenence, properly tuned, it wouldn't require any more or less maintenence then your stock compression.

In any case, Later!!!!

Aj
Dev
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Milling

Post by Dev »

Aj, once again, thanks. But, this tensil strenght on forged piston heads, I dont understand it. Tensil strenghth is the strength it takes to pull something apart. Wouldn't compression strength be a more effective validation. What am I missing?

Anyway...I am debating wether or not to remove my car from the road and make it strictly auto-cross. I would like to crack the block and uprade the guts as well as compression. Why can't perfect timing be re-acquired after milling, isn't TDC TDC, does this mean to acheive perfect timing you would have to machine custom cam gears to make up for the gap distance between p/head and valve. Would the same apply to a thinner HG.

Forged pistons sound good, would you recomend a set? Pistons and connecting rods....should they be bought together?

Finnaly.....I live in Massachusetts, we are not known for our women, weather or race tracks. Anyone who reads this that is in the New England area, w/i 100 miles of Lowell MA, please recomend a decent race shop, we have a bunch of hacks in Lowell.

thanks DEV
Aj
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forged

Post by Aj »

Tensile strength has a lot to do with piston skerts cracking, and rods bending, the point I was trying to make, is that any forged either piston or rod will take a substancial amount more abuse then stock.

TDC is TDC, but, I'm not reffering to cam timing, I was reffering to ignition timing, ussualy the timing needs to be retarted up to 2.5 degrees, depending on how much you mill it, which is partly the case with higher compression pistons, in the case of milling though, you really have no good estimate as to how much your compression went up, so it's hard to gauge the thin line between a lot of timing, and detonation, funny that you mention cam timing, because you really need to be careful of that too, because with milling, unlike higher domed pistons, you move the whole combustion chamber closer, rather then just a small section of the pistons, which ordinarily have valve reliefs cut any way.

With pistons, most manufacturers have gone through the trouble of already figuring out what you're compression should be, all else constant, in addition have taken into account proper valve clearance amongst many other variables, that you probably would even think about. If you read head gasket labels such as Spoon and Mugen, they say: "about", or "as much as". In otherwords it's more of a vague estimate and although probably very close, not perfectly accurate.

Forged pistons and rods are really nice, and I would recomend a set if you have the money to blow, although, they really aren't necesary for a daily driver, or even for most all motor street cars that are really pushing it. A set of factory CTR pistons ussualy would do the trick for less than half the price of a nice set of after market forged pistons.

Later,
Aj
Dev
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decisions

Post by Dev »

Thanks again Aj.

Dev
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