tweakedlogic
Well-Known Member
- Joined
- November 4, 2003
- Messages
- 950
- Reaction score
- 2
- City, State
- memphis, tn
- Year, Model & Trim Level
- '92 XLT
I am no stranger to porting. I have ported every intake and head that I have installed on my vehicles. So while I was fixing a coolant leak from the lower manifold behind #6 cylinder, I decided to get the die grinder out.
First let me state that if you decide to port, you assume all risks.
I do not recommend you do this with a dremel. It can be done. But it takes longer, it is harder to reach deep, and you will use many more sanding rolls.
Most people think of porting as gouging out the head for massive flow. This is not true in most cases. the best method is to simply smooth the flow for less restriction. Keep the ports as close to stock as possible to maintain high velocity of the intake charge. Really all I do it remove casting imperfections and irregularities.
This is not something you can do in an hour or two! It took me two hours just to get the lower intake manifold off. I spent about 3 hours porting the lower manifold. Patients will pay off in the end. try to rush things or use a bit that is too aggressive and you will damage things or make you motor run poorly.
We are not reshaping or enlarging. Only smoothing things out. Primarily I pay most of the attention to the outside bend of the port. That is where the air will be flowing. Kind of like a weight on the end of a string. That is the most important part of the port. I don't care what the outside of the intake looks like. And i spend very little time on the inside of the bends. I only want to improve flow while keeping velocity high.
First you will need a mini die grinder (variable speed). They cost about $30-100 depending on the brand and the store. Snap On is very proud of theirs. you will also need sanding rolls, the shank for said rolls, and some 200 grit emery cloth.
I use the $22 package of rolls from Harbor Freight. The kit includes two shanks, tapered rolls and straight rolls in two grades, 80 and 120 grit.
First remove the lower intake manifold. I will not cover how to do this. If you don't know, buy a manual.
Separate your sanding rolls first by type, then by grit. you will not need the 120 grit until you are 80% finished.
Clean, clean, clean. All of that oily carbon will clog your rolls. It has to go. It is best if you have an adjustment to control your top speed of the die grinder. if you spin it too fast, the rolls don't last as long and they fly apart.
Start at the top of the lower intake manifold. I left the fuel rail on. I did this because it does not line up perfectly with the ports. i wanted to correct that as much as I could. Plus it left me with an extra upper intake gasket i can use later.
this is a pic from the top of the #6 port before porting. Note the bulge on the very back of it. the other ports don't have this. Do not try to remove all of that bulge. there is not enough metal. We will shape it slightly to reduce the restriction.
Begin with the 80 grit straight rolls. One port at a time. You are only going to rough in the port at this time. Don't worry about the corners of the port until you have finished with the straight rolls. Get to 80% finished with the straight rolls, then switch to tapered rolls. It does not take much at all in the corners.
Don't over do it. you will not be able to remove every imperfection. Think of it like this... Your truck was running fine with all of the restrictions before right? no need to waste time. get it close and be done.
you want it to look about like this for now. this is about 80%. Perfect for where we are. Make every port look like this before moving on.
See the line all the way around the top of the port where the fuel rail mates up? and the divot in the middle of port? Leave those. They are nothing to worry about. I know it's on the outside bend. But trying to smooth that out would take too much material away.
To be perfectly honest, I cheated here. I used a stone with a very light touch to knock down this bump a little. Unless you are experienced i don't recommend you do this. Stick with the sanding rolls. All you want to do is reduce the bump and smooth the flow over and around it. It should look like this.
Now we are finished with the top of the ports. On to the bottom part. (head side) Still using 80 grit and still only sanding to 80% finished port. I found it best to use a bench vice with soft jaws (wood) and clamp the mani on it's side so you can get to the ports without it scooting around. work one side at a time.
I took a worn out roll and scuffed this port so you could see what it is we are really doing hear. All of the shiny parts are high spots. We are only removing the high spots.
Remember, a smooth delicate touch.
This is 90% finished.
Nearly there. Patients.
You now have the entire lower intake manifold 80% finished. You can go ahead and install this for some minor gains (after cleaning). But why stop here? Another 30-45 minutes and it will be perfect.
it is time to switch to 120 grit rolls. Same deal. start with the top do every port with straight rolls, then switch to tapered. Then repeat with the bottom.
It should look like this when you are finished.
Top
Contrary to popular belief, you do not want a mirror shine. I we say polish, but if you get it too slick you will hurt performance. Think of the port surface like a golf ball. those little dimples help the ball to spill air around it to fly faster and farther. So with that in mind you can consider this finished. Just because I was taking pictures and making a write up, I decided to use little pieces of 200 grit emery cloth on the end of my finger. to remove some of the sanding scratches. It takes another 30 minutes to do this.
I was hoping this pic would turn out better. You can't really see inside the ports, but you can see the studs I placed in there to hold the gasket for the valve covers. Nice little tip that will prevent much frustration.
So now you are finished. I have not yet ported my upper. this isn't a big deal to me now because i have an extra I can work on later, and I already have a spare gasket. I will add that to this write up when I finish it.
Use brake parts cleaner and compressed air to really clean your parts before you reinstall. Every nook and cranny must be free of the dust and grit you just created. Use your die grinder with a 3M scuff pad on the gasket mating surfaces first.
Congratulations, you have improved air flow and cleaned of all that carbon.
Ideally, you would also port your TB, upper intake, heads, and run headers with a 3 angle valve job. But all of that is not necessary. Just your intake will improve flow and volumetric efficiency. I would ported my heads, but there was no reason to remove them and I needed my truck back for the camping trip this week end.
First let me state that if you decide to port, you assume all risks.
I do not recommend you do this with a dremel. It can be done. But it takes longer, it is harder to reach deep, and you will use many more sanding rolls.
Most people think of porting as gouging out the head for massive flow. This is not true in most cases. the best method is to simply smooth the flow for less restriction. Keep the ports as close to stock as possible to maintain high velocity of the intake charge. Really all I do it remove casting imperfections and irregularities.
This is not something you can do in an hour or two! It took me two hours just to get the lower intake manifold off. I spent about 3 hours porting the lower manifold. Patients will pay off in the end. try to rush things or use a bit that is too aggressive and you will damage things or make you motor run poorly.
We are not reshaping or enlarging. Only smoothing things out. Primarily I pay most of the attention to the outside bend of the port. That is where the air will be flowing. Kind of like a weight on the end of a string. That is the most important part of the port. I don't care what the outside of the intake looks like. And i spend very little time on the inside of the bends. I only want to improve flow while keeping velocity high.
First you will need a mini die grinder (variable speed). They cost about $30-100 depending on the brand and the store. Snap On is very proud of theirs. you will also need sanding rolls, the shank for said rolls, and some 200 grit emery cloth.
I use the $22 package of rolls from Harbor Freight. The kit includes two shanks, tapered rolls and straight rolls in two grades, 80 and 120 grit.
First remove the lower intake manifold. I will not cover how to do this. If you don't know, buy a manual.
Separate your sanding rolls first by type, then by grit. you will not need the 120 grit until you are 80% finished.
Clean, clean, clean. All of that oily carbon will clog your rolls. It has to go. It is best if you have an adjustment to control your top speed of the die grinder. if you spin it too fast, the rolls don't last as long and they fly apart.
Start at the top of the lower intake manifold. I left the fuel rail on. I did this because it does not line up perfectly with the ports. i wanted to correct that as much as I could. Plus it left me with an extra upper intake gasket i can use later.
this is a pic from the top of the #6 port before porting. Note the bulge on the very back of it. the other ports don't have this. Do not try to remove all of that bulge. there is not enough metal. We will shape it slightly to reduce the restriction.
Begin with the 80 grit straight rolls. One port at a time. You are only going to rough in the port at this time. Don't worry about the corners of the port until you have finished with the straight rolls. Get to 80% finished with the straight rolls, then switch to tapered rolls. It does not take much at all in the corners.
Don't over do it. you will not be able to remove every imperfection. Think of it like this... Your truck was running fine with all of the restrictions before right? no need to waste time. get it close and be done.
you want it to look about like this for now. this is about 80%. Perfect for where we are. Make every port look like this before moving on.
See the line all the way around the top of the port where the fuel rail mates up? and the divot in the middle of port? Leave those. They are nothing to worry about. I know it's on the outside bend. But trying to smooth that out would take too much material away.
To be perfectly honest, I cheated here. I used a stone with a very light touch to knock down this bump a little. Unless you are experienced i don't recommend you do this. Stick with the sanding rolls. All you want to do is reduce the bump and smooth the flow over and around it. It should look like this.
Now we are finished with the top of the ports. On to the bottom part. (head side) Still using 80 grit and still only sanding to 80% finished port. I found it best to use a bench vice with soft jaws (wood) and clamp the mani on it's side so you can get to the ports without it scooting around. work one side at a time.
I took a worn out roll and scuffed this port so you could see what it is we are really doing hear. All of the shiny parts are high spots. We are only removing the high spots.
Remember, a smooth delicate touch.
This is 90% finished.
Nearly there. Patients.
You now have the entire lower intake manifold 80% finished. You can go ahead and install this for some minor gains (after cleaning). But why stop here? Another 30-45 minutes and it will be perfect.
it is time to switch to 120 grit rolls. Same deal. start with the top do every port with straight rolls, then switch to tapered. Then repeat with the bottom.
It should look like this when you are finished.
Top
Contrary to popular belief, you do not want a mirror shine. I we say polish, but if you get it too slick you will hurt performance. Think of the port surface like a golf ball. those little dimples help the ball to spill air around it to fly faster and farther. So with that in mind you can consider this finished. Just because I was taking pictures and making a write up, I decided to use little pieces of 200 grit emery cloth on the end of my finger. to remove some of the sanding scratches. It takes another 30 minutes to do this.
I was hoping this pic would turn out better. You can't really see inside the ports, but you can see the studs I placed in there to hold the gasket for the valve covers. Nice little tip that will prevent much frustration.
So now you are finished. I have not yet ported my upper. this isn't a big deal to me now because i have an extra I can work on later, and I already have a spare gasket. I will add that to this write up when I finish it.
Use brake parts cleaner and compressed air to really clean your parts before you reinstall. Every nook and cranny must be free of the dust and grit you just created. Use your die grinder with a 3M scuff pad on the gasket mating surfaces first.
Congratulations, you have improved air flow and cleaned of all that carbon.
Ideally, you would also port your TB, upper intake, heads, and run headers with a 3 angle valve job. But all of that is not necessary. Just your intake will improve flow and volumetric efficiency. I would ported my heads, but there was no reason to remove them and I needed my truck back for the camping trip this week end.