98Zam

I know the skill and knowledge it takes to port these heads are not common for people just to pick up a set and do it like a shop, but since I have my heads off...


I thought i could do some MILD MILD MILD work. I have a guy that has ported many sbc bbc heads, but yeah i know, all different for the ls1...


so what can be done? I feel bad not touching them AT ALL since they are already off and i have the tr 23o cam going in <img src="https://ls1tech.com/threads/images/graemlins/grin.gif" alt="" />



Can i just polish the intake and exhaust ports a bit? I hear this is where the major mistakes are made. So I figure if he just polishes that up nicely, just clean up with a .015 mill...




what about a valve job? or is this not a good idea since these are ls1 heads? suggestions????


EDIT by biggest concern is where to stop, is attempting a valve job on the ls1 heads too much? I dont see how a home mill and just polish could hurt that bad. I WANT TO BE SAFE about this, where should the line be drawn?

SoCal LS1's

Porting and polishing the exaust is not a bad idea, and you can port match them to your exaust manifolds using the gaskets. This is what I did since it was my first time. I can not stress enough if you have never ported a set of heads do not start with these. The intake is very complicated if you want good results, I had also heard polishing the intake does not allow the air and fuel to mix properly, so I stayed away from the intake completely. If you have the $ buy yourself a set of stage 2 heads while it is apart. This is to save you time later down the road when you wish you had, I sure do <img src="https://ls1tech.com/threads/images/graemlins/laugh.gif" alt="" />

BIG PD

in my opinion its ok to port a "little" and i mean a little on both sides of the head. don't go overboard with it though or you really will mess it up. just take like the first layer of metal off so that the ports have that shiny metal look to them. thats what i do for all my buddies whenever we take heads off. really if you just have a little battery operated dremel your not even going to be able to change the shape of the port. so, so long as you keep it the same design and just clean it up a bit (ie: get all the little bumps out and what not) you should be alright.

99 Black Bird T/A

iTrader: (4)

Personally, due to the hassle factor, I'd go with a budget set of heads by one of the sponsors unless it's for learning and experimenting. just my .02 worth

98Zam

Thanks guys.


I am trying to learn from this, and make this set up as budget as possible. Since I am going to buy new heads next summer, I dont want to buy cheaper heads now. I just want to touch these up while I have them off. If I were to buy new heads now, I dont think I could buy the heads I WANT next summer. I am just learning (Id be there the whole time he works on them) and keeping this to a budget.

anyone else have anything to say? I would assume that "porting" the exhaust a TAD and just "polishing up" the intake is the way to go....?

DrkPhx

iTrader: (15)

I did my own heads. I had them off for some unscheduled maintenance and my budget was ultra-tight.
SO I did them. I didn't touch the valve bowl area, cleaned up the intake very mildy and took extra care with combustion chambers; just removed the flashing. The exhaust I sorta hogged out. I sent them to a local shop afterwards to clean the deck surface and had them glass beaded and new GM valve seals put in. Car runs fine and I didn't lose HP (gasp!). It's up you.

703crewchief

Porting the exhaust is no big deal. Go for it. The port is such a straight shot, its hard to mess it up. On both sides though, stay off the floor of the ports. you can smooth them, but remove the least amount of material possible on the bottom. Now, the inside of the intake is a bit sketchy. You can smooth and match, but be careful around the valve guide/bowl area of that port. That is where everyone really makes flow(besides bigger valve and valve angles), but it is a double edged sword. Mess up in that area and cause turbulence, effectively lowering your port velocity. It is also a good idea to get a junk aluminum head of any make, and practice with your Dremel. This way, you know what bits and cartridge rolls to use when it comes time to grind your heads. Good Luck!

Mikael

I'd avoid using a dremel. It won't allow you to use a very large bit, and its easy to dig in and make a hole. A die grinder and carbide bit would be better suited.

98Zam

Would you say a 3 angle valve job would be a bad idea then?

Smoke_Ford

I am also porting my own heads. Now seeing as how LS1 heads are different, your approach has to be different. The exhaust is cut and dry. Port match the GM factory gaskets. Then polish the hell out of them. On the intake side, smoothing is the best way to go for someone doing it themselves. If you want to get nutty, if you look into the intake port, and look up and to the right, there is this little nub. That nub is huge in air flow restriction. Now alot of shops that port heads will be hesitant to port up there. Truth is you can go farther than you think. That nub houses a hole for a bolt. You can shave that down a considerable amount. If I recall correctly, even if you shave and can see the bolt a little bit, I believe that is ok provided you replace the bolt with the right sealent. How could a valve job be bad? Do you mean Reem, knurl and burnish the guide, or 3-angle valve cut, or both? Another thing is the combustion chamber. What I am going to do is take off all the carbon build ups, smooth it out, and polish it. Where ever you polish something, it makes it harder for carbon to build up in your engine. I know people that port using the following tools: Desk lamp, die grinder, and an upside down milk crate in their backyard. Truth is, a head is a head. If you have ported heads before, and understand how the LS1 head works, you should be just fine.

Vents

iTrader: (9)

i guess it just depends on if your ready to do something that no-one else has the guts to do. i had a free set of heads and a die grinder laying around and decided to get after it. the last set i had on my car got destroyed by chunks of valve seat so i decided to practice on those till i found the tight spots. now, everyone that says these heads are diffrent. well that is right but, look at a set of 18* race heads and tell me that those are totally diffrent. same basic port design as any bbc or full race cyllinder head. the more heads you look at, the more you start to realize that many many cyllinder heads have the rocker arm bolts sticking down inside the ports. our heads are no diffrent. basically that and some basic bowl work can up the CFM numbers by almost 20. more than enough to make it worth it for somone that wants to save some cash and do it themself. basically if my heads flow half as good as they look, i'll be happy. here's a link to some pics.

http://photos.yahoo.com/bc/vince0718...=ph&amp;.view=

Smoke_Ford

You are a smart man. EXCELLENT job on the CC btw.

gMAG

iTrader: (1)

I did my heads with a Standard Abrasives kit and was warned by some not to attempt home porting. While I understand the warnings, they came out looking great, and I'm sure that they'll be just fine.
On these heads, there isn't much material to remove. When porting them, keep in mind that "less is more". You're only looking to smooth the bumps, but not in the intake runner where turbulence is created which helps to mix fuel.
Concentrate on intake and exhaust port matching, and, short side and outer radius. Don't go wild on the intake radii!!! This is where incomming air gets compressed, much like the small end of a funnel. It is at this point where you must keep porting as EQUAL as possible. I also did the intake and exhaust bowls. But, I feared a slip of the wrist with the die grinder and opted to MANUALLY complete the bowls.
Standard Abrasives website can be found with a search. On their site, there is a printable writeup regarding home porting. They make porting sound like a "walk in the park", but it is NOT with aluminum heads. Take your time, go slow, and finish your heads with a MILD port/polish in mind.

Coolvet

Great article! It can be found at http://www.sa-motorsports.com/diyport.htm

98Zam

Thanks for all the great info and sites to check out, much appreciated.


Now, far as matching the header gasket to the head... I plan to use Jet hot headers with GM header gaskets. The Jet hot and GM gasket combo is ok i assume?


It just looks like A LOT of material can be removed. Like 1/8 of a inch all the way around? I believe it, but it just seems strange. Does this sound right, and is it okay to use GM gaskets with Jet Hots?

Vents

iTrader: (9)

thanks smoke ;D

"They make porting sound like a "walk in the park", but it is NOT with aluminum heads. Take your time, go slow, and finish your heads with a MILD port/polish in mind."

well said, thats the key. aluminum is great to work with. but soft enough to screw up in a hurry ;D seriously though, they can be screwed up easily so just go slow and take your time.

BigTex

iTrader: (16)

I have home ported two sets of heads so far. I didn't expect to compete with the big boys on head porting. I was just like you - If I have them off, might as well clean them up, something is better than nothing. I bought a 1/4" flex shaft rotary tool and a head porting kit similar to standard abrasives. The larger bits are great compared to a dremel, and its a lot more quiet compared to an air powered die grinder. It will take you a long time if you go cautiously, so having the correct tools for the tasks will pay off.

I left the chambers alone and just removed the outer casting materials from the intake and exhaust ports. I did clean up the bowls. My goal was to remove the casting, but not change the shape. I found that where the seats are set in, there is a pretty uneven edge all the way around. I made that a smoother transition. I was extra careful not to bang up the valve seats so I wouldn't be forced to get a valve job if I didn't want to.

It can be done by hand if you take your time.

gMAG

iTrader: (1)

You might begin your porting job by completing all the exhaust runners first. Then complete the intakes. This way, you'll have acquired some skill with the die grinder in a less vulnerable area (exhaust) of your heads, before attempting the intakes. Best of results to you!

Smoke_Ford

The GM gaskets are the best. Your combo will be perfect. Exhaust leave alot of room to work with. And yes, start there. If you screw up, no biggie. Just smooth it out.

jlsnsw

You know what, go for it. There were the first actual set of heads that I had ever ported and they came out well. I did the porting under the watchful eye of my father, who has ported and polished tons of heads, but these were his first LS1 heads also. If you would like some pics for reference, I will send them to you via email. I posted here and LS1.Com for pics and some people were nice enough to give me some for reference.
Hope it comes out well, and let me know if you would like some pics.