i am about to start porting my 081 heads to go on the lo3 and have many questions...i have read the sitting bull thread and the sa porting page and it helped but i have to make sure cause i dont want to ruin a good set of heads i will link to the pics i took not to eat up bandwith of site then list the questions i have for them before. thanks John

okay first this is the junk set of heads im practicing on and i tried to polish the intake the same texture as the exaust would be just because its practice i will leave the intake 80 grit on my good heads...i couldnt get into the corners well even w/ the taper rolls is this the finish i would want on the exaust side or do i need it even shinier

 

dont know i thought it was linking them to the site they are hosted on but i guess it just displays them and uses image shacks bandwith but heres the next sets

okay next up are these indents and ledges at the top of the bowl area do these need to be ground down to match the bowl or is this the narrow part i keep hearing that to leave alone??




next is where the valve stem goes into the guide does this need to be level off to the bottom of the bowl area? ive seen some that were and some that arent in the threads.

 

these are shots trying to show the short side radius because mine appear to have a good flow to them, and im not sure if they need ground...the only lip is the same ring that flows all the way around like the one i showed around the top of the bowl about half an inch below the seat, is this what they refer to when smoothing the transistion of the short side radius? bare w/ me on the bad pics im doin my best w/ my video cam.

 

these are larger valve stuck in place of the 1.8 ones to show what i think is plenty of room and not much valve shrouding. what do u guys think the pic w/ the paper is actually cardboard from a package for the stones i got.

 

and these are the last ones just showing diff. parts wondering if u guys can point out the thin spots or whatever that i really need to be carefull of thanks so much if u can help as i said i dont wanna ruin these after paying 100 bucks for em shipped to the house and all the parts i bought to port them




any pointer are appreciated and i will update pics as i go
John
Spanky00185@yahoo.com

 

the first set of pics is the junk head and all the rest are the 081 heads i bought.

 

OK, make the finish on the intake runners fairly rough, just like 80 grit will. The exhaust ports are the ones you want to get as smooth and polished as possible.

On the second set of pictures, I'm not really sure how the port pockets got those cylindical inserts in there so deep. My heads didn't have anything that really looked like that ...

With the valve stems where they enter the pocket, you want to shape them like an aircraft wing as seen from one end. They actually call it an airfoil shape. Some of my 601 castings' stems were cut almost all the way down to the floor already and thus there wasn't a lot I could do with them.

On the short side radiuses (radii?) just make the turn as smooth and flowing as possible, eliminating any sharp edges.

I think you have enough room between the chamber edges and the valve. If you get the heads cut for 1.94" intake valves, ask the machine shop to cut a little extra on the outer sides of the chambers so that it doesn't become an issue anyway.

Good luck! I'm always glad to see someone take on this challenge. As you are finding, this isn't very hard at all, is it?

 

oh yeah on the first set of pics i was just practicing to see how polished i could get it i will leave it at 80 when i start on my good heads as seen in the rest of the pic....

i know those ledges are really sharp and stick out alot...and that is really the only part that is a sharp turn for the short side radius the actual wall is pretty smooth up until it reaches that ledge. i guess i will just grind that down.

and im just gonna stick w/ the stock valves on this time around although the seats look to have a couple of small nicks on em so i will get a three angle valve job.

yeah im goin to do a little bit more practice this evening after work then start on the real deal.

 

It looks like you have lots of room for improvement with those heads. You really want to concentrate on the pocket, I've read somewhere that gasket matching the runners and smoothing them out is worth less that 3-5 cfm. You'll get 75% of your gains in the pocket, at least on factory heads.

On the short side radius, you want to do just that...radius it. The sharp edge left from the "bowl hog" that is done to do a quickie port job at the factory is what you want to eliminate completely. I start about a 1/8" below the valve seat and try to make it one continuously flowing transition to the port floor. What this does is keep the air flowing near the surface instead of separating once it hits the sharp edge. Then you want to smooth out the rest of the sharp edges on the sides and on the backside of the bowl and transition them to the port walls as well. The valve guide is a good place to remove some metal as long as you leave enough to support the valve. Most people try to contour it like a wing so the air is gently separated to flow around the valve.

The bowl area of the heads is very important because the velocity of the air is increasing at this point because it's acting as a nozzle (funnel). When air speeds increase they become more susceptible to separation and it doesn't like to turn direction. You’re not only speeding the air up, your asking it to make a near 90 deg turn. I'll see if I can find some airflow pics to help visualize what air does when it flows through ports.

 

sounds good my main concern was wether i needed to ground down those lips below the seat cause thats the only obstruction for the short side and i was thinking people mean the actually wall of the short side not the part where it meets the bowl....and if u have a pic of the shape u mean to try and get the guides shapped like a wing or airfoil im not quite following....i hope u mean on the sides of where the guide is and not the top of it...because id be affraid to actually shorten the guides like it appeared they were in sitting bulls thread. thanks for the input so far guys....any one know of the week points to watch out for in these heads or have pics or modify mine to show the weak spots?? that would be help ful so that i dont ruin these puppies. thanks
John

 

If you haven't been here already, most of your questions are answered here in great detail.

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

take a look this before and after picture, this shows how they rounded the short side.

 

after

 

yeah i have that article saved also....like i said the only restriction i found on the short side was that big lip that hung out which i will promply even out w/ the rest of the bowl!! thanks fellas much help as always
John