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Discussion Starter #1
This very well may be an inexpensive and effective power modification. I have been thinking about doing this for awhile.

Excuse my "Photo Shop" skills...

The green line is where the seal on the intake manifold seals. The blue lines represent the areas of the intake ports that I am considering opening up.

Besides opening up the ports, I'm also considering polishing the ports.


(Original photo taken by Shawn Hendrix of Childs and Albert)

Has somebody done this?

My strategy to make the ports identical is to make an outline of the shape of the ports that I want then mark the intake ports so that they are all the same size. Also use a piece of wood carved in a half moon shape to measure and maintain the new depths of the port. It will require skill to do this... (the more the better..)

Thoughts and ideas?


[ 11-20-2002, 01:52 AM: Message edited by: S. on Da 5 ]
 

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on the intake dont go any finer than 80-grit cartridge rolls. dont polish the ports out, not on the intake. do that on the exh side via cartridge rolls then a flap wheel and finally a buffing wheel bit.

seems like u should just go thru w/doin ur own diy head job though, a basic porting, some bowl polishing, and matchin ports w/manifolds. that would b worth ur time imho

-Ult
 

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idk what brought this animosity.

S- i have ported heads b4, chris has not. he gets it done for him. ask any1 who does headwork 4 a living if u take intake ports down 2 the same level of smoothness as the exh ports, 'no' will b the answer every time.

-Ult

[ 11-19-2002, 07:35 PM: Message edited by: UltegraSTI ]
 

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Discussion Starter #6
Originally posted by Blue01Street:
If you couldn't understand Ult's very hard to read post. Don't polish intake ports. Exhaust ports should be polished but NOT PORTED.
<font size="2" face="Verdana, Arial">I understood him... thanks


Looks like some debateable informacion in this post.

So how much power would this be good for?

[ 11-19-2002, 10:27 PM: Message edited by: S. on Da 5 ]
 

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both r ported, only exh ports r finely polished w/anythin more than about 80grit cartridge rolls, which is about where u stop on the intake. the exh after u port them u go farther than the intake by polishing them 2 mirror-like finish w/a flap wheel, then a buffing wheel bit.

yes u port both, just go into polishing the exhaust ports and the combustion chamber as much as possible 2 keep carbon buildup down, givin it little 2 stick 2. intake u leave it rougher (80grit) b/c it helps create swirl and help atomization of the air/fuel mixture on its way in. it doesnt have the issues of biproducts like carbon stickin on the way in.

i still have tools and bits from porting 302 heads...it usually goes like this, granted ally is more gently than cast iron.

intake port- stone/40grit/80grit
cumbustion chamber-80grit/flap wheel/buff wheel
exhaust ports-stone/40grit/80grit/flap wheel/buff wheel

now this is with 302 head, having not looked at a zetec head 4 a good while in depth, i would figure the tolerances on this modern head would b alot better, thus require less work, than old v8 heads.

-Ult

[ 11-19-2002, 10:01 PM: Message edited by: UltegraSTI ]
 

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hmm, this is very very interesting. I TOO would like to get my head ported and polished. So all I have to do is draw an outline, port, polish with a dremel and i'm done?? Dont we have to use mathematical measurements and equations to figure how the efficiency or not? Or do we leave it up to the CHIP/ECU (or other electrical devices that control fuel/air, timing,etc??) sorry just a few ideas from a newb!!
 

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Originally posted by chris_k:
hmm, this is very very interesting. I TOO would like to get my head ported and polished. So all I have to do is draw an outline, port, polish with a dremel and i'm done?? Dont we have to use mathematical measurements and equations to figure how the efficiency or not? Or do we leave it up to the CHIP/ECU (or other electrical devices that control fuel/air, timing,etc??) sorry just a few ideas from a newb!!
<font size="2" face="Verdana, Arial">4 a basic port job, u dont need 2 get exact chamber volumes and flow #s, just close. it'll b mild enuff that ur prolly already close, in some cases u get them closer 2 even than they were stock. remember ur diy is not gonna b as aggressive as a FC stg 3 or whatever. a basic port will give u great gains and its good when u do that work. but u should get a 3-angle valve job from a machine shop after ur finished ur port work, that will maximize ur gains from ur work.

but...do it right. get spare gaskets and machinist dy-chem (or bluing), here i found this site 2 help u better understand what 2 do.

http://www.sa-motorsports.com/diyport.htm

-Ult

[ 11-19-2002, 10:08 PM: Message edited by: UltegraSTI ]
 

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Discussion Starter #10
Originally posted by chris_k:
hmm, this is very very interesting. I TOO would like to get my head ported and polished. So all I have to do is draw an outline, port, polish with a dremel and i'm done?? Dont we have to use mathematical measurements and equations to figure how the efficiency or not? Or do we leave it up to the CHIP/ECU (or other electrical devices that control fuel/air, timing,etc??) sorry just a few ideas from a newb!!
<font size="2" face="Verdana, Arial">Port and polish is a bit of a skilled art...

By making a diagram like I did... IMO it will help some... How much to open it up??? I am not sure... yes the fuel and timing tuned with this mod will help...

This is DIY mod IMO... If you have the time and confidence in your skills... (More skils the better)

[ 11-19-2002, 10:08 PM: Message edited by: S. on Da 5 ]
 

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S. 4 instance in Improved Touring Category of SCCA, as of last time i checked, headwork is limited 2 the 1st in of the port, essentially 2 clean up the port entrances and exits, u could do that. still get dy-chem and some spare gaskets 2 match ur port openings and 2 match ur manifolds 2 them.

if u didnt want 2 get 2 involved, then that would b a good option.

-Ult

[ 11-19-2002, 10:12 PM: Message edited by: UltegraSTI ]
 

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You can polish both the intake and the exhaust and not hurt anything(extrude hone). Being our motors are fuel injected, the fuel pressure/injectors take care of the atomizing of the A/F mixture. If fuel is puddling in the intake runners, it's because it's way too rich.
 

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UltegraSTI, If you have ported heads before and you claim to know what you are doing, then why not work in an automotive machine shop instead of a bicycle shop?

Hmmm, makes me wonder!
 

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Originally posted by Focaltech01:
UltegraSTI, If you have ported heads before and you claim to know what you are doing, then why not work in an automotive machine shop instead of a bicycle shop?

Hmmm, makes me wonder!
<font size="2" face="Verdana, Arial">that doesnt relate to anything?


anywho...yea you can all the time practice is the perfect for the practice the port
 

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Funny you bring this up... I just started porting an aluminum (non-Focus) intake manifold tonight.

I've been using my dremel so far with decent results... I've been going through the cartrige rolls like mad though...

Thanks for the info guys!
 

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Originally posted by OmniFocus:
Funny you bring this up... I just started porting an aluminum (non-Focus) intake manifold tonight.

I've been using my dremel so far with decent results... I've been going through the cartrige rolls like mad though...

Thanks for the info guys!
<font size="2" face="Verdana, Arial">which focus intake are you porting?
 

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UltegraSTI, If you have ported heads before and you claim to know what you are doing, then why not work in an automotive machine shop instead of a bicycle shop?
<font size="2" face="Verdana, Arial">Hey, what's wrong with that? I've done a lot of engine work for friend's before while I was a mechanic at a bike shop. I prefer to be called: "Dura Ace STI" though..
 

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<font size="2" face="Verdana, Arial">Quite an interesting read. Especially the part where it says we dont port match the exhaust manifold.

Forgive my newbie-ness
, but do the retainers/valve springs need to be removed to do this?

What are the marginal benefits from doing the chamber work? I dont have to do this step, right?

Are the red areas where the coolant flows through?


I ask, cause my buddy's dad is a machinist and he's been naggin me to get my head ported.
 

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Originally posted by chris_k:
ok so if we port the head to make it bigger, does this increase displacement?
<font size="2" face="Verdana, Arial">If you work on the combustion chambers themselves, it will increase the combustion chamber volume (which will reduce the compression ratio), but the only way to increase displacement is to increase the bore or the stroke. Displacement is a measure of how much volume the piston displaces from BDC to TDC.
 
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