well my father is porting my head, and he claims to know how to do it well, and i wanted to make sure he is doing it correctly, ok he claims you want the intake rough and the exhaust smooth, and he has grinded down the valve guides in the porting, i just want to know that he is doing it correctly, and im not the one to judge so im asking for one who is i mean everything looks clean except the valve guides he has grinded. everything is smoot as a babies bottom , besides the intake where he used a more coarse flapper wheel, but all looks wel to me, i will take pictures of it tonight, and post it on here. comments and suggestions are very well appreciated.

Gasket matching and polishing up is about all you can do without a flow bench. To gain optimum performance, a flow bench is a must. It measures the airflow in each individual cylnder and then you can also remove the dead spots by observing the flow through the cylinder.

Good Luck

The theory behind the rough finish on the intake and the smooth mirror polish on the exhaust is this, the intake side needs the rough type swirl polish to help create a better air fuel mixture. A smooth mirror polish might create a pooling or puddling of fuel on the intake port promoting a less than optimal combustion mixture in the cylinder.

Now on the exhaust you want a mirror polish to help stop the build up of carbon and lessen the chance of a hot spot on the exhaust port. This also helps to create a better flow of air out of the engine into the exhaust system.

Make sure he doesnt do any porting on the floor of the runners. He can smooth it but do not remove any material from the port floor. All the grinding should take place on the bowl, short turn, sides and roof of the runner.

As far as the intake side, Its not carbureted so a mild polish wont hurt a bit. With fuel injection, the fuel should be atomized when injected so you dont need a rough surface to prevent puddling. I wouldnt make it smooth as glass, but I also wouldnt keep it a rough cast.

As already stated, a flowbench is really needed so your dad can tell if he is helping or hurting flow. Also keep in mind that a ported head might look good but doesnt aleays help. Low lift and rpm #'s usually suffer after porting but with cams and rpm's, the head will start to come alive. Without cams but a lot of port work, your car might not do what you expect because of lack of velocity.

o boy, he ported te valve pockets and intake and the exhaust like hell, we looked at slowboyracings heads and it looked equivilant to a stage VI porting, which is more then i wanted. because i want a street car , i didnt plan on doing head work for higher rpms but if it is nescassary then i will. but he insisted he knew what he was doing so i didnt argue with him. we have no flow bench and he ported the hell out of everything he could, will get pics tommorrow the camera is at his shop and i forgot it , and what part is the "roof"? regardless i know he ported the floor and the roof. like i said it looks like it would flow better , but i have no idea , we dont have a flow bench nor do we have access to one , if worse comes to worse then i have an extra head and i will just swap them, (hate to waste a cometic headgasket)

compression said:

o boy, he ported te valve pockets and intake and the exhaust like hell, we looked at slowboyracings heads and it looked equivilant to a stage VI porting, which is more then i wanted. because i want a street car , i didnt plan on doing head work for higher rpms but if it is nescassary then i will. but he insisted he knew what he was doing so i didnt argue with him. we have no flow bench and he ported the hell out of everything he could, will get pics tommorrow the camera is at his shop and i forgot it , and what part is the "roof"? regardless i know he ported the floor and the roof. like i said it looks like it would flow better , but i have no idea , we dont have a flow bench nor do we have access to one , if worse comes to worse then i have an extra head and i will just swap them, (hate to waste a cometic headgasket)

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The floor, of course, is the bottom of the port and the roof is the top of the port. Stock exhaust ports have a low pressure area on the floor of the due to the exhaust trying to make the sharp turn from the bowl to the runner. The intake ports actually have a low pressure area right at and past the short turn radius due to the intake charge making the sharp turn into the bowl. When the roof is raised from porting, the air is given a straighter shot into the cc but when the floor is lowered, the low pressure area is turned into more of a turbulent area. This is because when the floor is lowered, the intake or exhaust charge has to make an even tighter turn into the cc or ex runner.

If you do pull the head, just reuse the cometic. As long as they arent damaged, they will reseal fine. Just coat the gasket with copper coat spary to help promote sealing.

well we did it all by eye ,its all smooth no real tight turns or corners so im hoping it flows good , the only thing im concerned about is he grinded the stock valve guides down all the way flush with the port. this concerns me because all the ported heads ive seen have the valve guides still whole and stil present not mutiluated thank you for the help, i use the reputation thing, if you help me i help raise your reputation.

compression said:

thank you for the help, i use the reputation thing, if you help me i help raise your reputation.

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You sound like a crack head.

oldman said:

You sound like a crack head.

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yea i guess so eh

Darn Murderators

Old Mitsu Tech said:

Darn Murderators

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Please stay on topic. wise..ass...I mean man.

ok you two .. , so by porting the floor, it causes more turbulance in the port and makes the flow more restrictive?

After reviewing your mods list. Porting your head should not have been one of the first things to do. But, since all is said and done, here's my two cents.

Grinding down the valve guide wasn't exactly the brightest thing to do considering that it will greatly alter how oil sits in the guide. Actually, I predict disaster from grinding down the valve guide, but I have no evidence to show for it.

However, a rough floor is desired on the intake side to encourage atomization of fuel. There are even things people do to encourage this effect. Some people use a punch and make divots along the floor and roof of the port, something to consider. Exhaust ports are already properly sized but could use a polish. If you increase the flow area too much, you will lose flow velocity. Unless you're spinning your motor to 9k+ the gains from opening the ports will be marginal.

Porting the head for one of the first mods isn't the best idea in my opinion. Wes Hess put it best when he said "Porting your head as your one of your first modifications is sort of like buying and engagement ring for the girl you haven't met yet"

compression said:

, the only thing im concerned about is he grinded the stock valve guides down all the way flush with the port. this concerns me because all the ported heads ive seen have the valve guides still whole and stil present not mutiluated .

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Cutting the guides in the port will not hurt anything at all. Most full race port jobs include removing the bottom of the valve guide. It has been done for ever and never caused any issues. It does, however, increase flow in and out of the combustion chamber. Someone else stated that it creates some oiling issues but that was more of an uneducated guess than anything based on fact. The valve seal is still intact and in the same location so nothing has changed there. Just make sure the bottom of the guide has been deburred before reassembly. If not, you run the risk of hanging a valve open.

Cutting the bottom of the valve guide off means less support for the valve, and will shorten the life of the valve and the guide. Thats about it, thats the reason most street head porting does'nt include that mod.

ltho98 said:

Porting the head for one of the first mods isn't the best idea in my opinion. Wes Hess put it best when he said "Porting your head as your one of your first modifications is sort of like buying and engagement ring for the girl you haven't met yet"

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yes i guess it is huh, well i understand this , but my mod list is what i have know and i have differene things going on this engine, like a balance shaft eliminator kit, new rings, new rod bearings, (mostly stock internals) arp studs, cometic headgasket (i think i mentioned this before) tubular exhaust manifold , evo 3 16g , 3"o2 housing with ext dump,3"exhaust turbo back, small fmic 2.5" intake piping,and maft and afc for tuning devices (maft mainly used for mafs relocation for atmo dump and stock mafs elimination) and tune for 25-27 psi and i plan to build my head to handle 8500-9000k rpms whenever i can find a good deal on a 90 eprom and im also heavily looking for a sheet metal intake manifold, a magnus or a bulldog style. or building my own along those lines.

compression said:

and i plan to build my head to handle 8500-9000k rpms whenever i can find a good deal on a 90 eprom and im also heavily looking for a sheet metal intake manifold, a magnus or a bulldog style. or building my own along those lines.

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Good luck with that 90 eprom search... I know they're hard to come by. I'd recommend get ing the cheapest 1g eprom you can find and, if its a 1991+, swap the pins and do this.

Also, I have come to understand that the 1G head and 1G intake mani combo is not that bad up top. I'm running the stock intake mani and I don't feel a drop off in power (or enough to warrant spending the money for a magnus smim). If you are going to get a SMIM, I recommend the Magnus. It has had exceptional reviews.

Dsmonster is correct that the 1g head and manifold combo is fairly decent, at least for stock parts. Its no honda cylinder head but it can hold its own. Porting the 1g head is pretty much useless until 600whp. I've seen too many cars on unported 1g heads trap in the mid to high 130s some in the 141 range. Good valve springs and some big cams and a good sheet metal intake manifold are gonna drastically increase the torque curve up top to maintain a strong HP curve. These two mods should be done before porting the head IMO. The Magnus is a good manifold as mentioned by dsmonster and I also like the JM fab manifold as well. Couple 9sec dsms have switched over from the magnus to the JM for some topend gains and its manufacturing quality is fantastic. The welds hold extremely well, well enough to have the sheet metal balloon before breaking the welds, this happened on a buddy's preignition problem

dsm-onster said:

Good luck with that 90 eprom search... I know they're hard to come by. I'd recommend get ing the cheapest 1g eprom you can find and, if its a 1991+, swap the pins and do this.

Also, I have come to understand that the 1G head and 1G intake mani combo is not that bad up top. I'm running the stock intake mani and I don't feel a drop off in power (or enough to warrant spending the money for a magnus smim). If you are going to get a SMIM, I recommend the Magnus. It has had exceptional reviews.

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thank you sir! i have been looking for this information for some time now, (im not a good searcher , i get frustrated) so you hack the transistor , and get a 91 coil pack , and swap the pins? can you send me a link for pin swapping? , i bought a 90 talon tsi awd about 2 years ago (had bent valves) and i let it rot. noly its completel junk, parts car only , and i was looking for parts for it , and i noticed this talon had the 91+ hacked transistor and coil pack, so i have everything to do it =) but i will look for a cheap 90 eprom still to try and avoid this project. thanx

compression said:

thank you sir! i have been looking for this information for some time now, (im not a good searcher , i get frustrated) so you hack the transistor , and get a 91 coil pack , and swap the pins? can you send me a link for pin swapping?

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Sure, here's the pins you need to swap and a comparison between the pins of each ecu.

i finally got a few pictures of it (well alot) and i found it kinda hard to take good pictures but here is what i got.


**Pics removed**please read the rules on size. If they are bigger then the rules state, then links ONLY will be posted.

hoooooly shit i didnt mean to make them that big... god im sorry for you 56kr's , soo do you think that first pic will flow enough? haha looks like you can drive a mini cooper through that porting , by the looks of it on the picture ...

soo what do you think?

No way to really tell if you get an improvement out of that without the use of a flow bench. It could be your typical "Buff and Fluff" port job where it looks pretty but flows like crap. Typically 60 grit is good enough to smooth out the port while still giving it a rough finish while 80 grit or higher will work for exhaust ports. As someone stated before becareful with the floor of the intake ports, removing a little bump there could cause drop in flow/performance. Most likely your valve guides will need to be machined to remove any burrs since they were ground down and as some one stated before they will wear out faster. You might want to get that head tested since all of the ports were touched. Find someone with a flow bench equipped with a tumble meter. Remember 4 valve heads require the air to tumble while your typical 2 valve heads require the air to swirl.

I disagree with the guy that posted that you want the intake side to be rough....You said that if it is rough, it prevents puddling...It is a fact that polishing the intake side will prevent polishing because when the metal is polished, fuel doesnt get a good hold of the metal, unlike rough metal which will allow the fuel to grab onto the metal...And if you want a good air fuel mixtute, do not knife edge the divided in the intake, this will allow little turbulance needed to mix the a/f.