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hey all! its been a while since ive been on. anyways i finnally started back on my build since i blew the last engine up. i have a few questions about porting my head. ive been having a hard time finding any good tips about where to remove material on the ports. i think i pretty much have the exhaust ports how i want them (reduced the short angle and blended the seat rings with the port) and i opened them up to just about the size of the gasket. but im having a hard time finding a way to improve the intake ports. also im looking to buy a nice stage one cam and im leaning towards the skunk 2. anyone have good results with this one? all motor with a lil nitrous, headers exhaust aem intake and thats about it. thanx for the help!!!!! Paul. P.S. ill post pics of the progress in a lil bit.
 

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On the intake side the y8 head is pretty decent right from the factory.
However there is a sharp angle on the short turn radius which will force the air into the middle of the port, which will reduce air velocity as it will be hitting the valve.
(think of it as a wing in your intake tract)
So this should be your first port of call.

After that start removing casting slag that is left in the ports, this is the easiest way to improve your head.

To help even the flow between the long and short radius of the port, you should add more dish into the bowls. Im assuming you know what the bowls are, but just incase....its the area just at, and after the valve stem on the long turn radius. (have a look at this bisimoto page to explain why this works) http://www.bisimoto.com/wst_page6.html
Read from "my experimentation with fluid dynamics..."

After that, the web that seperates the air between the two intake ports should be made sharper, but you should radius the edge to about the diameter of a pencil led. And then smooth this sharp edge into the rest of the port towards the valve.

The intake port area, up near the intake manifold gasket, doesnt need to be opened up. It only needs to be smoothened out. Opening it up more than a small bit will increase flow but will reduce intake velocity and the anti-reversion effect of the port. (which prevents air from flowing back up the intake tract as the cylinder fills)

For portmatching on the intake side, the intake manifold, gasket and intake port should taper in that direction. This further helps the anti-reversion effect.


On the exhaust side, il link you to a thread where i explained the what to do.
http://www.d-series.org/forums//showthread.php?t=83051
The second last post.
Il explain it again in more detail if you want, as i dont think i explained it properly the first time.

Dont polish on the intake side, this will merely take the fuel vapor out of suspesion and make it stick to the walls. ideally you want a 600-800 grit finish.
On the exhaust side you should polish somewhat, as it prevents carbon build up and reflects heat back into the exhaust flow. But you shouldnt polish it too a mirror finish as a) it takes too much time, b) exhaust gases still contain vapour that will come out of suspension like on the intake side and disrupt the flow and c) carbon deposits are going to stick to the walls anyway, so a slightly rough texture isnt the end of the world.



Like i said in the other post, the head work ive done has only been NA. It is only based on my experiences and books/articles that i have read, so is by no means the last word in head porting, its just stuff that has worked for me so far.

As far as the cam goes, i havent put a cam into a d16 yet so i dont have any experience of my own, but people on here tend to recommend crower, bisimote and gude.

If you have any questions just ask.
Oh, just remembered, here is a link to a head porting website that has allot of information http://www.TMossPorting.com/tabid/3682/Default.aspx
 

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Take a look at my thread (http://www.d-series.org/forums//showthread.php?t=67263) this is my engine build of a y8. The pictures of the ports start on page 5. I didn't go all out and extreme on it, I simply created smooth transitions, eliminated casting flaws, blended the bowls and seats together, left the intakes slightly rough, and polished the exhaust, as far as the chambers go, the y8 chambers are damn near perfect from the factory so I deburred and polished the piss out of it, didnt really remove any material at all. I took a little off the inside of the seats cause they were cut for oversize valves anyway. take a look and maybe it will help you on your journey
 

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wow man that is a redick. build!!!! thanks for the help!!! i really needed the pics of the intake and exhaust bowls cus i know thats where they need work. im workin on the head again tonite and ill try to get some pics up. thanx for the help!!! oh yeah, is a stage one cam a waist of time? i just dnt have the money to soak into new valves and springs and retainers. i have about 600 to spend on parts after the machine shope soakes up 220 for the valve job and milling.
 

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damn thats a high price for that machine work. i got mine re-built, valves re-ground, hot tanked, bead blasted and milled for 200
 

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milled .025....3 angle valve job, hot tanked. and valves and springs reinstalled. you get what you pay for too dnt forget that...this is one of the best shops in my area to. i dunno u really think thats to high?
 

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no i didnt know you were getting all that done. thats not too bad. and to your cam question, you can run a stg.2 cam with OE vavles and retainers, but you need springs and a good tune
 

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