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Drag Racing Lover
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191 Posts
Discussion Starter · #1 ·
Well, I finally got the courage to start porting on my "062" Vortecs. I'm gonna fully port the exhausts and just barely clean up the intake ports along with gasket matching the intake and heads. I'm cutting the guides and seats, pulling the pressed in studs, tapping and installing shoulderless screw studs (gonna run self-aligning rockers so I don't have to cut the stud boss) and hope for the best. I think I am done with the carbide cutters on the first head and ready to do the final finish on the exhaust ports with cartridge rolls. Here are a few pictures. Please let me know if you think I'm headed in the right direction, completely off base or just plain ruined this head already. If I haven't ruined the head, please give me your advise on how i'm doing and any tips you have. Thanks, Ted.
http://www.hotrodders.com/forum/attachment.php?attachmentid=70253&stc=1&d=1357179111
http://www.hotrodders.com/forum/attachment.php?attachmentid=70254&stc=1&d=1357179111
http://www.hotrodders.com/forum/attachment.php?attachmentid=70255&stc=1&d=1357179111
http://www.hotrodders.com/forum/attachment.php?attachmentid=70256&stc=1&d=1357179111
http://www.hotrodders.com/forum/attachment.php?attachmentid=70257&stc=1&d=1357179111
 

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Drag Racing Lover
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191 Posts
Discussion Starter · #2 ·
If you run the bit back and forth it will dig a hole and cut too deep on the outsides. Ends with a crown in the middle.

Sanding rolls will help smooth out the pinch points around the guiides. Might need to tear some off to get into the deepest part. Take your time and use smooth cuts agasit the direction of the bit. Dont use die grinder air power does not have good tq and will stall the bit and dig a hole when it does. Electric is much easier to control and produces a smoother finish. But dremel is not going to cut it you will need something with a hp rating and works at low and fast rpm.

Focus on just removing the ruff casted surface and leaving a smooth cut finish. Hanging the shape is not always the best idea. Usally the shape is made with a purpose in mind and is not easy to redesign with just cutting the port and not adding metal back in. This basic clean up will net you a real 3-5 percent increase.

Also changing the shape of the port can really mess up swirl porting and other flow devices that will actually hurt flow when the air is moving at hundreds of mph thru the port.
First off, thank you for the advice. Do you think I have hurt the flow on these exhaust ports? Like I said earlier, i'm not gonna do any cuttin on the Intake ports. I'm tryin to get these ports to look just like the ones in David Vizards book and it looks like he cut alot of the guide to make a smooth area completely around it and blended it into the exiting port. I have been using my die grinder cut down to 30psi. I'm gonna try to get to Lowes tomorrow and get a light dimmer to use with my electric die grinder as its way to fast if plugged into an outlet, 25,000 rpms if i'm not mistaken.
 

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Drag Racing Lover
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191 Posts
Discussion Starter · #4 ·
Put on your big boy pants and use both hands.....:rolleyes:
Well I would if I could but I have a problem, big boy britches dont fit me due to me not havin much of a butt. I mean flat, flat as a flitter! Not only that but i'm kinda, sorta not comfortable with the way that thing jumps around and slings cartridge rolls apart. By the looks of what I have done so far do you think I need to cut a little more with the carbide cutters or go with 80 grit rolls?
 

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Drag Racing Lover
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191 Posts
Discussion Starter · #6 ·
Aleast read this link and consider building it.A good tool to have in any hot rod shop.







Flow Bench
Thanks for the link. I have done a little reading on home flow benches and plan to do alot more. If I can, or better said, when I can, get this porting trick down pat I want to build a flow bench. Right now i'm just doing my best to not ruin the heads, lol. That Vizard feller has a heck of alot of talent when it comes to making power and he has a section in one of his books on building a flow bench. I think with more reading, and I read some and glanced some at the article you posted, I can build a pretty accurate one by combining information from both articles. Thanks again for the link!
 

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Drag Racing Lover
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191 Posts
Discussion Starter · #8 ·
Looks fine. You can thin and streamline that big fat valve guide boss some more. So the air can go around it.
I was hoping you would chime in. After comparing pictures of mine and some of Vizards I don't think i'm ready for the cartridge rolls yet, lol. When you say streamline, do you mean taper the guide boss into the runner? Also, I read somewhere about not taking very much at all from the back side of the boss. I have looked at your profile pictures and didn't find any but do you have a picture or two of a completed exhaust port that you have done? Am I right by not messing with the intake bowl? I really do value your knowledge.
 

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Drag Racing Lover
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191 Posts
Discussion Starter · #9 ·
Why not the intake ports? That's where most of your gains will be made.
Well now, maybe I need to reconsider as everything I have read thus far says that on the Vortecs the intake side is close to impossible to improve and I figured with my very limited knowledge on porting I would be best to leave them be. What were you thinking needs to be done on the intake side?
 

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Drag Racing Lover
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191 Posts
Discussion Starter · #10 ·
Flow bench is not as useful as it might seem. Yes it helps and good bench numbers equal good hp numbers if everything else is right. But remeber the first thing they tell you when using a flow bench is its only about 1/4 the speed and pressure of a running engine. The real engine will force air thru the head much faster than a small vacum can. So yes they work but can lead to poorly ported heads if you do not understand flow to begin with.

Air flows down the center of the port. the air along the walls is moving very slowly and not really where the largest flow comes from. but air moving down the center of the port can reach and exceed the speed of sound. Your goal as a porter is make the port flow enough air to get close to the speed of sound as possible without going past the mark becasue air get tubulent after that. But until it reaches that speed it will increase in flow to the cylinder as the speed increases. Until you reach the tipping point where the air get turbulent. Since the flow bench cant actually push air with that much pressure most of the time you need to calculate the port size and shape. and when that i done it is almost always smaller than the one you have in front of you to cut.

Here is what I use to port heads. this is a little small for the job with cast iron car heads but will work. But its amazing on alum car and bike heads. If you want it perfect this or a tool like it is the only way to go.

K.SRH440, Industrial Kit with heavy duty shafting, 115 Volt

Foredom has been making precision tools for many years and a lot of professional use them. Price sucks and they dont go on sale. This would produce much better results for your money spent than a flow bench. Now both should solve a whole lot of problems. But most head porters make there own tools. Or use tools they have had for years to do certain parts of the heads.

If you want to become a master at porting best to go to the junk yard and buy about 20 heads off anything and start cutting. Eye and ear protection is very important. Your not a porter until you been to the hospital to get a burning hot peice of metal removed from your eye. Also is a really good way to remeber to where your safty glasses. One trip to the hospital and you never forget again.
Now that sounds like just what I need!! I like the foot controller and really really like the flexable shaft idea. I never knew this tool even existed. Thank you for showing it to me! I do plan to get into porting heads as I have several friends that race, I build and tune their carbs, and its something I can do sitting down for the most part. I have several pairs of safety glasses and am a firm believer in them. When I get in from the garage tonight I'm gonna do some more reading on this tool and may just order me one. For everything that comes with it, $355.00 is kinda cheap. I paid almost $200.00 for my 8pc. carbide cutters.
 

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that's actually about half way through, its also very important to blend the chamber in with the top cut of the valve job- which can be very tricky. I also didn't thin the guide any in that pic, typically I do thin it some but not as much as a lot of people do.

Just blending in the bowl cut and the top cut of the valve job on those heads will pick up 15 cfm, that area is very critical, and very tricky and time consuming as you do not want to nick the valve seat. smoothing out the short turn a little can help too, just don't get carried away. In general the areas closest to the valve seat are the most important. Also, enlarging the pushrod pinch a little and getting a nice and even contour on the roof will help with higher rpm power.
 

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Be sure to wear a dust mask or respirator. I had a pair of heads boiled in cleaner once before I ported them and lost my voice for two days from breathing the acid dust.
 

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Drag Racing Lover
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191 Posts
Discussion Starter · #15 ·
I got the guide bosses cut down and shaped as close as I could to the pictures in Vizards book. These pictures don't show the shape very good but they come to a point on the top of the guide and taper down. I'm kinda skittish on taking anymore out. Do ya'll think I should leave the intake ports alone or port them as well? Also, finished all the guides on this head. From the pictures it looks like I cut the spring seats but I just skimmed the top to knock the varnish/dirt off. Please let me know what ya'll think not only about the intake ports but all the stuff I have done thus far. I plan to either start pulling and taping the studs tomorrow or, if ya'll think I need to port the intakes or any other stuff, i'll do that. I do know i'm really enjoying this, lol. Here are the pictures
http://www.hotrodders.com/forum/attachment.php?attachmentid=70273&stc=1&d=1357282581
http://www.hotrodders.com/forum/attachment.php?attachmentid=70274&stc=1&d=1357282581
http://www.hotrodders.com/forum/attachment.php?attachmentid=70275&stc=1&d=1357282581
http://www.hotrodders.com/forum/attachment.php?attachmentid=70276&stc=1&d=1357282581
http://www.hotrodders.com/forum/attachment.php?attachmentid=70277&stc=1&d=1357282581
 

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Drag Racing Lover
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191 Posts
Discussion Starter · #16 ·
What is the date code on your vortec heads. It's stamped on the exhaust side flange, on a machined surface area.
I don't have any pics of my ported vortec heads. I did them quit a while ago. They are on my 406.
2.02x1.60. I never took any pics of those.
With the stock 1.94" valve intake port you are best to just smooth and generally clean up, whats there.
The form under the valve is quite good. At least on the early Canadian made heads. 1996-2000.

The later mexico heads are smaller, low less in stock form and can use dome more work.
How you port thee heads is dependant on how they are going to be used.
The port shape you want for a big cam big valve lft "race" is different than the port and bowl shape thats best when the valve stays relativily close to the seat. small moderate duration and lift.

The vortec head has really good low lift flow in stock form. for a mild mtor do no remove the critcal funnel shape of the bowl under the valve job.
You can generally streamline the guide boss so air can go around it.
Flowing the garden hose thru the port will help you see the natural flow path on a SBC head.

Post all the stamped numbers that are stamped on your heads. May need a light and some emery paper to see them.
On the exhaust flange.
I'll get those numbers today. I did buy a pair of "062" that came off a running 2000 Chevy truck for $125.00 the other day but these i'm playin with are not them. By looking at what i've done on the exhaust in the pictures do you think I have improved them? By lookin at em and imagining(sp) in my mind the air flowing thru them I feel i've helped them but I would like your opinion. I will post the numbers a little later.
 

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Drag Racing Lover
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Discussion Starter · #17 ·
First off, Thank you for the great info. I ordered some longer mandrels, for the cartridge rolls, and they should be here today. I didn't get tired I just didn't want to take to much off the guides for fear of exactly what you said, weakening the guide. These are the heads I plan to run and I want them to last alot more than 20K miles. After looking at the pictures on the computer I did see where they are definately not the same. They look different just by lookin at them. I'm gonna get some numbers for FBird in a little bit and post them and i'll do a little "Tweaking" and try to get them as close to the same as possible. I don't have a way of cuttin the valves myself, although I have done it a few times on a schools machine, but I am gonna lap them in good. I "may" talk to my machine shop friend about what you suggested on cuttin the valves. There is a pretty big ridge under the intake seat, do I smooth it out and blend? I've read not to disturb it and also to smooth it out, lol.
They are not all the same but an improvement. They should flow well with a little more tweaking. Final cuts are slow and steady. If your tired same them for the next day.

Intakes are probably good for what they are. I would take off the ruff casting maybe even just use sand paper rolls for the intake side. The guide on the intake side are pretty tall. They could be cut but they will probably only be worth a few ponies and could result in bad flow if not done correctly.

Are these your heads your going to run or a set you are using to learn on. If its for learning purposes or all out racing. You can cut the guiide all the way put and leave a flush surface. I would think this should flow the best since these are not swirl port heads and rely on the combustion chamber to turn the air inside the combustion chamber and allow for the final mixing of the air as it flows past the valve and swirls into the port. But this type of short valve guide will crap out the seals and get wobbly real quick unless real guides are put in place first. But it will last 20k miles or a race season. I also thin the valve stems on the lathe to allow for more flow. Just dont do this with sodium filled valves. And back cut the seat area of the valve right down to the seat and allow for better flow over the valve. For bike race engines i will even round the seats with the flapper leaving the valve flat and rpunding the seat in the head and lap the valves in to seat them. Give a lot better flow at low lift levels that will allow the engine to get more air moving sooner in the intake cycle.

Valve size is also usally only at the seat where is touches the head. So moving the seat right out to the edge of valve will increase the effective valve size. And allow more flow at first opening event which allows more air to flow across the entire intake cycle.

Sorry for the short discription it would take hours to go over everything but for your heads a basic clean up should be all that is needed.

Hope this helps.
 

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Drag Racing Lover
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191 Posts
Discussion Starter · #18 ·
What is the date code on your vortec heads. It's stamped on the exhaust side flange, on a machined surface area.
I don't have any pics of my ported vortec heads. I did them quit a while ago. They are on my 406.
2.02x1.60. I never took any pics of those.
With the stock 1.94" valve intake port you are best to just smooth and generally clean up, whats there.
The form under the valve is quite good. At least on the early Canadian made heads. 1996-2000.

The later mexico heads are smaller, low less in stock form and can use dome more work.
How you port thee heads is dependant on how they are going to be used.
The port shape you want for a big cam big valve lft "race" is different than the port and bowl shape thats best when the valve stays relativily close to the seat. small moderate duration and lift.

The vortec head has really good low lift flow in stock form. for a mild mtor do no remove the critcal funnel shape of the bowl under the valve job.
You can generally streamline the guide boss so air can go around it.
Flowing the garden hose thru the port will help you see the natural flow path on a SBC head.

Post all the stamped numbers that are stamped on your heads. May need a light and some emery paper to see them.
On the exhaust flange.
The numbers I found are: 10, 062, 8, 18, M127, GM-D, 12558062. Are these what you need?
 

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all this porting is a great idea.Remember that almost all the heads need the most work on the exhaust side. Doesnt matter how much air goes in the intake side if it cannot leave
 

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This is 100 percent true. Most factory heads work well because the intake side is under a lot pess pressure to pull the charge in than the exhuast side. The exhuast is going to come out. Because the piston is going to force it out. Most factory heads are very unbalaced because of this fact.

But with heads designed for efi you got to assume it is also built to run with little to no over lap. Now with a poor flowing exhuast port a larger cam with good overlap will not scavange like it is designed to so the exhuast ports always need attention first when starting with an efi head.

Most ford guys are amazed to see the exhuast bump in the 80s and 90s 5.0 engines. It blocks most of the port and by itself its worth 20 hp and will make sure any bolt on you install only works so well. This is also the reason some cars will respond to bolt ons and make 500hp and other will never pass the 300 mark.

On the intake side in this case i would think there isnt much power to be gained past the removing of the ruff casting surface to a smoother sanded surface.

Some none efi heads have the opposite problems. Balance is the key and getting the ports to flow enough to support the rpm the cam is requesting from the engine.

Just some general info to spur discussion.

it's actually 100% wrong... a 5cfm gain on the intake is worth more than a 5cfm gain on the exhaust, even though the % difference is smaller.

Also, the Vortec intake tract is better than previous sbc heads, but the exhaust is NOT worse, its actaully a hair better too, just not as much as the intake. People get caught up in the intake/exhaust ratio and fail to see what they're really looking at on the exhaust side. Also, there's NO crossover, which is a pretty big deal compared to most other stock sbc heads.
 
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