porting intake ports on heads
porting intake ports on heads I searched and read that taking .050 off the side walls on the intake ports would be about right...I saw that a couple of times...anyone of you DIY porters disagree?
Also, only take material off the top of the exhaust port.
That's all I could find. Not many DIY porters here on the board I guess.
Also, only take material off the top of the exhaust port.
That's all I could find. Not many DIY porters here on the board I guess.
Joined: Apr 2006
Posts: 3,911
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From: Grand Rapids, Michigan
You'll get the most gains by smoothing the short turn radius from the valve bowl inward and blending the valve seat into the throat of the port. Narrow the valve guide boss and taper it to a point. The port walls are the least of your worries. That area of the port flows a significant amount of air stock, so unless you're doing some max effort porting, the only thing you'll succeed in is lowering your port velocity and losing low and midrange power. Hope this helps.
well I was told by several people on here that if you dont know what your doin, dont touch the short turn radius. you got it right above, thats the short turn radius. its where it falls off into the bowl area. all I did was smooth it. and yes, you should widen the int. ports slightly. I didnt and I think thats why my high lift #s arent that great. the rest of my #s are OK, Im happy with my results. just wish my .500-.650 lift #s were larger. anyways, you'll remove material mostly from around the guides, and opening up the bowls to match the size of the valve seat throats. the transition from bowl-seat should be very smooth. also, I was told by several porters no to put a "edge" on the guide, to make it round. the edge will create turbulance and not a smooth turning point for the air. you'll also notice that pic you have posted, there is no swirl ramp. I left mine in, just cut it down about 50% and rounded off the edges. you can see pics of my heads in my thread from thursday.
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I ported the stock LS1 heads my self. i don't have dyno numbers but i will post later once i dyno the car. what i did was :
1- porting the valve bowl until it is even with the port roof.
2- removing some material from the valve guide boss.
3- removed the rocker arm hump in the intake port and smoothed the
place until it is even with the port wall.
4- smoothed the short side radius and the floor of the intake by polishing
(no porting here).
5- i used stock valves.
6- matched the port roof to the bowl.
7- didn't open up the port walls much just slight opening.
8- did the same things above to the exhaust ports.
hope that helps.
1- porting the valve bowl until it is even with the port roof.
2- removing some material from the valve guide boss.
3- removed the rocker arm hump in the intake port and smoothed the
place until it is even with the port wall.
4- smoothed the short side radius and the floor of the intake by polishing
(no porting here).
5- i used stock valves.
6- matched the port roof to the bowl.
7- didn't open up the port walls much just slight opening.
8- did the same things above to the exhaust ports.
hope that helps.
Last edited by Abdullah; Jan 13, 2007 at 10:44 PM.
Originally Posted by dubrado
2- removing some material from the valve guide boss.
smooth the valve bowl to make a smooth transition to the valve seat? (shown in red)
is this the hump you're talking about?
Originally Posted by Abdullah
3- removed the rocker arm hump in the intake port and smoothed the
place until it is even with the port wall.
place until it is even with the port wall.
1- porting the valve bowl until it is even with the port roof.
I can't see that in my mind
Last edited by dubrado; Jan 14, 2007 at 02:37 AM.
Originally Posted by dubrado
this is the valve guide correct?
Yes, this is the valve guide boss.
2- removing some material from the valve guide boss.
smooth the valve bowl to make a smooth transition to the valve seat? (shown in red)
No, the valve bowl is more the red area it is the area under the valve seat except the short side turn. not smooth but port the enlarge the bowl area until it is matched to the valve seat and also match the roof to the bowl.
is this the hump you're talking about?
Yes.
1- porting the valve bowl until it is even with the port roof.
I can't see that in my mind
Yes, this is the valve guide boss.
2- removing some material from the valve guide boss.
smooth the valve bowl to make a smooth transition to the valve seat? (shown in red)
No, the valve bowl is more the red area it is the area under the valve seat except the short side turn. not smooth but port the enlarge the bowl area until it is matched to the valve seat and also match the roof to the bowl.
is this the hump you're talking about?
Yes.
1- porting the valve bowl until it is even with the port roof.
I can't see that in my mind
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this one shows you would you need to be shooting for in general. smooth transitions from intake port all the way out the valve seat. total removal of the rocker stand hump (notice the hole), use a steel burr to open up the steel valve seat to blend it into the bowl, and smooth it up to, but not touching, the actual seat thats cut into the seat insert.
I removed all the material arond the guides and smoothed into the roof.
I left the ramp intact, some poeple remove it entirely. Ive talked to a few pro porters and they all said leave it in there for air quality. not sure why ALL the aftermarket heads out there do not incorperate it though. and Ive seen other people here remove it all together and get higher flow #s then I did. but I decided to take there advice and leave it in.
be very careful about not hitting the valve seat angles with the die grinder or bits. mine comes close to hitting the chuck when Im porting deep inside. I need to get a longer mandrel for the sand paper drums. and to help keep you from scratching the deck surface, I learned to put a layer of 3M auto grade masking tape. dont worry about it if your planning on getting them decked. which I highly recomend to help with gasket sealing and to improve compression. here's that pic again with some highlighting lines.
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hope this helps you out. start with cutting burr's, then use course sand paper drums, then fine drums for exh. side, and medium grit drums for intake side. these pics were after the rough drums. notice the grit marks in the ports. the smooth and medium will be much finer then that.
[/IMG] [IMG]
[/IMG] this one shows you would you need to be shooting for in general. smooth transitions from intake port all the way out the valve seat. total removal of the rocker stand hump (notice the hole), use a steel burr to open up the steel valve seat to blend it into the bowl, and smooth it up to, but not touching, the actual seat thats cut into the seat insert.
I removed all the material arond the guides and smoothed into the roof.
I left the ramp intact, some poeple remove it entirely. Ive talked to a few pro porters and they all said leave it in there for air quality. not sure why ALL the aftermarket heads out there do not incorperate it though. and Ive seen other people here remove it all together and get higher flow #s then I did. but I decided to take there advice and leave it in.
be very careful about not hitting the valve seat angles with the die grinder or bits. mine comes close to hitting the chuck when Im porting deep inside. I need to get a longer mandrel for the sand paper drums. and to help keep you from scratching the deck surface, I learned to put a layer of 3M auto grade masking tape. dont worry about it if your planning on getting them decked. which I highly recomend to help with gasket sealing and to improve compression. here's that pic again with some highlighting lines.
[IMG]
[/IMG] hope this helps you out. start with cutting burr's, then use course sand paper drums, then fine drums for exh. side, and medium grit drums for intake side. these pics were after the rough drums. notice the grit marks in the ports. the smooth and medium will be much finer then that.
I had pretty good results with these, if youre interested. Sadly I dont have any finished pics, but plenty or pics mid way through.
http://picasaweb.google.com/GuitsBoy...dPolishedHeads
http://picasaweb.google.com/GuitsBoy...dPolishedHeads
