Yes, I want to tackle porting my LS head myself. Can someone break it down for me a little on what I am try to accomplish? Ive done extensive research and basically this is what Ive picked up, someone please verify this.

Intake runners = roughed up for better fuel atomization
Exhaust = polished and shiny?


How much do I port and is there a "professional" way to measure this?

Basically someone with some experience, your help would be appreciated.

 

I do prefer the intakes to be a little rougher than the exhaust, but smoother than stock. I do like to polish the exhaust to help prevent carbon build up ( however it still builds up ). Basic port work is to just clean the roughness of the stock port. Use the sanding drums and not a carbide bit. Mainly want to remove the casting flash that is on the sides of the port runners and simply smooth out the roughness.

Professional way to "measure" a heads port work is to have it Flow-Benched. It will show if the ports are balanced and how much cfm they can flow.

 

to add to jimbo.. knife edging the port split will help as well.

 

Good point. However I only knife edge the exhaust divider and not the intakes. Think of air going over the wing of a plane, only the back side has a knife edge while the front side is nice and rounded.

 

Don't worry about the finish. Worry about the shape. There is so much more to it than any crap online could teach you. All you can do is dive in head first and learn. You HAVE to give yourself a measuring stick of flow bench and dyno or you are just making metal shavings and not learning a thing.

Most of all.....have fun.

 

just saw this on the Powerblock

http://www.powerblocktv.com/episodes...r-head-porting

 

see senior.. But the back side of the separation is still round in shape, so I dont really see this as being an issue. as your still creating low pressure areas by the split which helps move the air IIRC..

 

correcto infacto ... we cant stop him though hehe

 

Strange that you say that, when I first tried my hand at porting my z6 head I was told NOT to knife edge the intake split, but to give it more of a round finish. I also have a fully ported a6 head that I have not installed and the divider is not knife edge either.

I think the real way is to really know is with a flow bench and time slips (mph). There are also many books and articles that you can read about it.

 

Knife edging has been proven on the flow bench to be alot more effective for velocity then then the rounded edge, thats the reason it is used on nearly all professionally ported honda heads.

OP, while this picture i have here isnt the best port job because of the tools used, it gives you a general idea of what your trying to accomplish. These pictures i put side by side of each other to show the steps involved in changing the shape of the port. They were given to me by the person i bought this head off of who had it ported at a shop who provided pics of the process. It was done with a cast iron carbide burr which is NOT recommended for aluminum that is the reason why it has deep cuts, you are supposed to use an aluminum burr for this process which provides a smoother finish. It is also not recommended to cut the guides clean off either, unless you plan on replacing them, but this is a common thing you will see on alot of CNC ported heads.



The last picture on the right is the way i received the head, and it is NOT what your finished product should look like. I had to go over these ports with finer grit sanding rolls, cleanup the sharp and rough spots, crossbuff, and then "hone" with a 120 grit plateau brush to give proper surface finish for atomization of fuel.

Which you can see here....

 

Thanks for the input spawne, we may not have the same meaning of ''knife edge'' though from what I see in your pics. What I was talking about is making the divider really like the sharp side of a knife. Maybe the pics don't do it justice but that to me looks more like the back of a knife, even though it is sharper that stock.

 

very difficult to get that kind of knife edging your talking about without a CNC port

 

that port work from "shop" looks like complete a-hole. smh

 

you would be correct, it looks like ****, but the shape and size was right, and the miracles i performed after cleaning it up turned out good.

 

yea.. meant the shops work you had to fix.. lol When I did my own port work years ago, I practiced for months on beat up parts prior to doing it myself.. It really does matter if you learn VS being told... You can destroy a head in no time..

 

My recommendation is to simply do a casting cleanup. Leave the factory shape but smooth out the casting flaws. Play it safe and there's no risk of ruining the head.

 

Dont really gain anything by doing that either, better off leaving the head stock and investing in a 5 angle valve job.

 

yuppers.. If your going to touch the ports , save the money and have a reputable shop do it. Unless you own a flow bench and the how too, no sense in wasting your time. You could adversely effect the flow characteristics.

 

Well the point was that he is going to attempt this himself. Which is why I recommended if he really wanted to touch the head just keep it safe and make it look pretty lol. I wouldn't say you won't gain anything but if you're striving to get the most power on a budget, it's probably a good way to pick up a few HP. Just a lot of time invested to do so.