Home porting on heads?
03-15-2004, 04:23 AM
#41
On The Tree
here are a few pics I could scrounge up...
One is a set of 853 castings (the 'dirty' looking heads)
the other is a set of 243 LS6 heads. The car they went on picked up 40RWHP and TQ in a stalled A4
One is a set of 853 castings (the 'dirty' looking heads)
the other is a set of 243 LS6 heads. The car they went on picked up 40RWHP and TQ in a stalled A4
03-15-2004, 04:31 AM
#42
On The Tree
Just add a bit more of my mindless rabble 
I start with carbide cutting bits to shape the port, then move on to cone shaped sanding drums, and then finally I like to use the crosshatch buffers on the exhaust and even use the roughest one on the intakes very lightly. I've found it gives the exhaust ports a good mirror finish to them that help reduce carbon buildup significantly, and on the intake side it doesn't seem to hamper air/fuel mixture, but cuts back on any PCV related oil film buildup. I only use the roughest buffer VERY lightly on the intake though. Also, WD-40 and the fine buffer creates a GREAT thick fluid that acts a polishing compound to produce a mirror finish.
I've got pics somewhere of the 317 castings I did for myself recently, but I was in a severe rush and opted not to do the intake runners at this time, so only the exhaust runners and the combustion chamber got done. It's for a heavy nitrous build, so the intake can wait for a rainy week later
Here's a candid pic of me just after finishing the 243 castings recently BTW, that block of wood you see covered by a rag is my bit holder. It's got about 30 different size/shaped carbide bits. My long 6" bits are fewer and stored in a nice pouch 
I start with carbide cutting bits to shape the port, then move on to cone shaped sanding drums, and then finally I like to use the crosshatch buffers on the exhaust and even use the roughest one on the intakes very lightly. I've found it gives the exhaust ports a good mirror finish to them that help reduce carbon buildup significantly, and on the intake side it doesn't seem to hamper air/fuel mixture, but cuts back on any PCV related oil film buildup. I only use the roughest buffer VERY lightly on the intake though. Also, WD-40 and the fine buffer creates a GREAT thick fluid that acts a polishing compound to produce a mirror finish.
I've got pics somewhere of the 317 castings I did for myself recently, but I was in a severe rush and opted not to do the intake runners at this time, so only the exhaust runners and the combustion chamber got done. It's for a heavy nitrous build, so the intake can wait for a rainy week later
Here's a candid pic of me just after finishing the 243 castings recently
BTW, that block of wood you see covered by a rag is my bit holder. It's got about 30 different size/shaped carbide bits. My long 6" bits are fewer and stored in a nice pouch
03-15-2004, 08:29 AM
#43
On The Tree
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Its good to see a post like this. I am fairly new to LS1's, only had my car a month, but I am excited to put some "touches" on it.
I used to have a GTP that I ported the heads on. I gained a good 0.4 in 1/4. That was with no cam, stock valves. I did alot of reading before I went at it. there was more in it with a cam. It was a 12.9 car, but I never ran slicks, my best was a 13.3 w/2.15 60ft. I took the approach of "less is more".
Yes, I used a dremel
(black and decker wizard actually) for this simple fact alone. It was slow. Being my first time, I wanted to take my time. I think it turned out pretty well.
I have a full compliment of airtools now that I acquired for other projects. So if I decide to do my own heads, it won't take nearly as long.
Alot of people say they won't be as good as aftermarket. They are right. Most aftermarket designs have went through a trial and error process to get the most power. But if you can do it for ALOT less cash, it makes the DIY alternative alot more attractive.
DEE
I used to have a GTP that I ported the heads on. I gained a good 0.4 in 1/4. That was with no cam, stock valves. I did alot of reading before I went at it. there was more in it with a cam. It was a 12.9 car, but I never ran slicks, my best was a 13.3 w/2.15 60ft. I took the approach of "less is more".
Yes, I used a dremel
(black and decker wizard actually) for this simple fact alone. It was slow. Being my first time, I wanted to take my time. I think it turned out pretty well.I have a full compliment of airtools now that I acquired for other projects. So if I decide to do my own heads, it won't take nearly as long.
Alot of people say they won't be as good as aftermarket. They are right. Most aftermarket designs have went through a trial and error process to get the most power. But if you can do it for ALOT less cash, it makes the DIY alternative alot more attractive.
DEE
03-15-2004, 11:22 AM
#44
Launching!
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Pulled the head off my vette and was surprised by how good the design of the LS1 runners are. I expected to have to do more porting work but I am just going to concentrate around the valve step and remove that rocker stud bump in the intake. The rest will just be a cleanup and maybe open up a little.
Two questions:
1. Is there enough metal to completely remove the rocker stud bump in the intake?
2. Can I port match the exhaust to 1-7/8" headers or am I going to hit a water jacket or something?
PS. Also found out I have a LS6 block casting
Two questions:
1. Is there enough metal to completely remove the rocker stud bump in the intake?
2. Can I port match the exhaust to 1-7/8" headers or am I going to hit a water jacket or something?
PS. Also found out I have a LS6 block casting
03-15-2004, 12:46 PM
#45
On The Tree
there is enough metal to remove the rocker arm bolt 'bump' HOWEVER you will end up opening up into the threads of that hole. it's not a big deal though and is done pretty much across the board with other head porters.
I woudn't worry about trying to port match the exhaust side honestly. There's probably not enough meat there to begin with, and the exhaust ports are VERY good from teh factory anyway that opening them up that large will probably cause you to lose ALOT of exhaust velocity and ultimately low end torque.
I woudn't worry about trying to port match the exhaust side honestly. There's probably not enough meat there to begin with, and the exhaust ports are VERY good from teh factory anyway that opening them up that large will probably cause you to lose ALOT of exhaust velocity and ultimately low end torque.
03-15-2004, 12:58 PM
#46
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The rough intake ports are like the dimples on a golf ball. The turbulent air at the surface level acts as a buffer for the higher speed air passing over it. Kind of like an "air lubricant" so to say. If you have seen the new commercial for the car where they flip it over to show the dimples on the bottom and the increased air flow you kind of get the idea.
03-15-2004, 03:37 PM
#47
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Originally Posted by mbaskett
there is enough metal to remove the rocker arm bolt 'bump' HOWEVER you will end up opening up into the threads of that hole. it's not a big deal though and is done pretty much across the board with other head porters.
I woudn't worry about trying to port match the exhaust side honestly. There's probably not enough meat there to begin with, and the exhaust ports are VERY good from teh factory anyway that opening them up that large will probably cause you to lose ALOT of exhaust velocity and ultimately low end torque.
I woudn't worry about trying to port match the exhaust side honestly. There's probably not enough meat there to begin with, and the exhaust ports are VERY good from teh factory anyway that opening them up that large will probably cause you to lose ALOT of exhaust velocity and ultimately low end torque.
What are your thoughts?
03-15-2004, 04:38 PM
#48
On The Tree
Well, I dunno. One one side, I think being able to smoth that surafce out is a great idea, but on the other, more pessimistic side of me, I worry about the backfill material ever working loose, or cracking/splitting and then dancing the tango with your valve seat 
I've gone as far with some to do that portion of the porting with the rocker arm bolt installed and torqued, and it helps, but because of the tip of the bolt design, it doesn't completely 'fill' in the hole. It's better, but not perfect.
I think the only way I'd feel 100% confident is to have that hole TIG welded closed and then have the rocker bolts shortened appropriately. I can't speak to the durability of the Loctite compounds in this application, as I've never tried them, nor researched their hardness/durability properties when heat cycled and exposed to gasoline. I'm guessing you work at/for the company Loctite? If so, maybe you and I could work together to find something that does function reliably and safely.......
Along with the durabiltiy concerns, you also have to figure in pressure that could be applied when you tighten the rocker arm bolt down, and possibly compress the air inside the hole, since the oil on the topside can semi seal the air's escape path. It's not a 100% occurance, but is a possibility and would need to be addressed.
I've gone as far with some to do that portion of the porting with the rocker arm bolt installed and torqued, and it helps, but because of the tip of the bolt design, it doesn't completely 'fill' in the hole. It's better, but not perfect.
I think the only way I'd feel 100% confident is to have that hole TIG welded closed and then have the rocker bolts shortened appropriately. I can't speak to the durability of the Loctite compounds in this application, as I've never tried them, nor researched their hardness/durability properties when heat cycled and exposed to gasoline. I'm guessing you work at/for the company Loctite? If so, maybe you and I could work together to find something that does function reliably and safely.......
Along with the durabiltiy concerns, you also have to figure in pressure that could be applied when you tighten the rocker arm bolt down, and possibly compress the air inside the hole, since the oil on the topside can semi seal the air's escape path. It's not a 100% occurance, but is a possibility and would need to be addressed.
03-15-2004, 07:30 PM
#49
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Think of your motor as an air pump and the more air go into the motor and out of the motor, the more power you can make. So, porting the runners and valves angles speeds up the volume and velocity of the air if ported correctly. By increasing the angles and the number of angles greatly helps the air flow in and out of the chambers.
Your local machine shop can machine your valves and seats to the desired size. Normally a 3 or 5 angle valve job is performed.
Simple things to remember: The bowl and valve seat area is the most critical area to port/polish correctly. Remember never, never, never, blend your bowls or valve angles into the first seat angle. (Angle closest to the combustion chamber). Example, on the exhaust side, the first angle is never to be touched. Start blending after the first angle. On the intake side blend up to the second angle. If you want better flow numbers, only blend 1/2 of the second angle and stop. Don't blend the complete second angle. This is your maximum point to stop at. The closer you can get to the first radius (angle) the more air will flow but don't blend into the first angle and 1/2 of the second angle or you will mess up the flow. Make sure your blending and polishing is on a radius. (semi circle shape or semi moon shape). This helps flow. Helps create an hourglass which creates a vacuum effect and speeds up air flow.
Before you try blending your angles you have to know what specific dimensions you are opening your valve seat surfaces to. This is determined by your valve size. PM me for the correct calculations. If you are putting in larger valves then your machine shop might have to replace your stock seats with larger seats. If you remove extensive amounts of the seat, the seat can become weak, fatique and "fall out" or "break" and this is bad. Any good machine shop can determine if you need new seats. You will want to make sure your valve angles surfaces are perfectly round as you blend and port, or a egg shape open can occur, causing air tumbling which stops air flow.
Best trick in the book is to machine a old junk valve down to the size your valve opening needs to be (pre-calculated by the size of the new valve) and then stick the valve in the opening. Once you have port/polished matched the size of the machined junk valve to the new valve opening it should fit in like a hand in a glove. Then you can also drop the valve into the bowl and see any discrepancies in the bowl. Again there is a million and one things you need to know, but this is a start. Until you understand the whole principle I would keep asking questions. Once you have the principles down then I would practice on a junk head until you are comfortable. Make sure you know what sizes all you angles should be ported to (bowls, runners exhaust, intake openings) before starting. Incorrect measurements will kill you heads!
Your local machine shop can machine your valves and seats to the desired size. Normally a 3 or 5 angle valve job is performed.
Simple things to remember: The bowl and valve seat area is the most critical area to port/polish correctly. Remember never, never, never, blend your bowls or valve angles into the first seat angle. (Angle closest to the combustion chamber). Example, on the exhaust side, the first angle is never to be touched. Start blending after the first angle. On the intake side blend up to the second angle. If you want better flow numbers, only blend 1/2 of the second angle and stop. Don't blend the complete second angle. This is your maximum point to stop at. The closer you can get to the first radius (angle) the more air will flow but don't blend into the first angle and 1/2 of the second angle or you will mess up the flow. Make sure your blending and polishing is on a radius. (semi circle shape or semi moon shape). This helps flow. Helps create an hourglass which creates a vacuum effect and speeds up air flow.
Before you try blending your angles you have to know what specific dimensions you are opening your valve seat surfaces to. This is determined by your valve size. PM me for the correct calculations. If you are putting in larger valves then your machine shop might have to replace your stock seats with larger seats. If you remove extensive amounts of the seat, the seat can become weak, fatique and "fall out" or "break" and this is bad. Any good machine shop can determine if you need new seats. You will want to make sure your valve angles surfaces are perfectly round as you blend and port, or a egg shape open can occur, causing air tumbling which stops air flow.
Best trick in the book is to machine a old junk valve down to the size your valve opening needs to be (pre-calculated by the size of the new valve) and then stick the valve in the opening. Once you have port/polished matched the size of the machined junk valve to the new valve opening it should fit in like a hand in a glove. Then you can also drop the valve into the bowl and see any discrepancies in the bowl. Again there is a million and one things you need to know, but this is a start. Until you understand the whole principle I would keep asking questions. Once you have the principles down then I would practice on a junk head until you are comfortable. Make sure you know what sizes all you angles should be ported to (bowls, runners exhaust, intake openings) before starting. Incorrect measurements will kill you heads!
03-16-2004, 06:39 AM
#50
Originally Posted by c5blkvette
Thanks Matt. After I grind through, I think I will shorten the bolt by about 5mm, screw it in and then "back-fill" it with epoxy and smooth out the runner. I am sure I can find some good epoxy here at Loctite (perhaps one called Aluminum Liquid w/ 20% aluminum).
What are your thoughts?
What are your thoughts?
Chris
Edit: I meant to mention that I had a pipe coming off my intercooler (in a turbo application) that I epoxied in three places. It was a custom fabricated pipe where I bought approximate mandrel bent angles and then cut and the pipe bends to the exact angles I needed. One of the cuts was too large to weld close (over 2 inches at the widest point) so I ended up using epoxy. Very tough environment because the intercooler was not bolted in (just sat on a rail) so the pipe saw ALOT of vibration. It was also (obviously) in a pressure environment and I ran up to 15psi. Since it was on the outlet of the intercooler, air temperatures never rose above 120F but it did see plenty of engine heat during stop and go traffic.
Last edited by rotarnomore; 03-16-2004 at 06:49 AM.
03-16-2004, 06:51 AM
#51
Launching!
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Originally Posted by rotarnomore
Epoxy would be just fine. I think people underestimate the strength of epoxies because they are "glues" but in some applications, they can be stronger than a weld. Welding heats and oxidizes the surface of the metal which can reduce its strength. Epoxies have low temperature cures and won't fatigue the metal. I would have no worry with an epoxy as long as you select one for the right application and properly prepare the surface.
Chris
Chris
Here is a link...note petroleum resistance, aluminum shear strength and thermal resistance.
http://loctitetds/tds5/docs/HYSAE-214HP.pdf
03-19-2004, 01:11 AM
#52
Fuel pooling and air-fuel mix are why you don't polish the intake ports. Same porting for FI but the head may benefit from a disproportionately bigger exhaust valve as per East Coast Supercharging....EX: 2.02/1.6. I did that and those sizes fit the stock seats. (LS6 heads)
