Joe,

I like your quote in the sig...

"If you are hated,you have succeeded" (my machinist)

Bret

 

Usually true too!

 

I can assure you it is...LOL

 

You know, sometimes I get the impression that some of you type just to hear yourself type.

I really doubt that most of the readers here that _really_ have to ability, equipment and experience to seriously consider porting a set of heads are really foolish enough to believe that you can just go ahead and hog out some ports and have good results, so I’m not sure what repeating the same spiel every time someone brings up the topic is really helping.

Instead of hearing the same “leave it to the pros, don’t mess your stuff up” line it would be a lot more interesting to see some discussion of port profiles that work, the good/bad spots on a set of LT1 or SBC heads, tricks for figuring out what works and doesn’t, maybe a SERIOUS discussion of port volume vs velocity vs power production (the few times that I tried here I got shot down right away with a “I’m not telling my secrets”)….

I for one have had some fairly decent luck (IE ended up with an engine that made the hoped for power or better in the powerband that I expected without any drivability maladies) with a few instances of home porting. At best I used a make shift flowbench (could just measure vacuum in in of water, the readings didn’t have any correlation to anything else besides before and after readings to check for the effect of changes) and some port templates, at worst I’ve done “what looked right.” I’ve also considered trying to work out some sort of velocity probe…. But to be really honest, you can probably come by a good 70-90% of the potential improvement from a good porting job just by knowing that the port profile and assorted sections are supposed to look like. It’s getting that last bit of the potential flow where all the real artwork and testing equipment comes in.

For that matter, I know that there are a few people that frequent this board that have good to awesome results with a bunch of hours of home porting. Of course, I’m sure that everyone was just really lucky, right?

 

ws6-ta,
How do you know what material to remove?,
if you don't know what final shape you want?

What shape is best?
How is 'best', determined.
I certainly hope that people here don't think that
a One PSI { 28 in h2o} flow test, tells the whole story.

The actual pressure difference is much higher than
one psi for most of the intake stroke, and things
don't scale when speeds get trans-sonic.

 

Good discussion.

I've ported my own heads more than a few times. The results were "ok" but nothing to scream about. I took everything I had seen in some really good heads and tried to replicate that in my own work. Problem was... I could see the port shape but I didn't know WHY some porting was different from others. I didn't know the seat angles used or how that effected the port. I didn't know what the valve sizes were or whether the valves had been moved or how that would need to be compensated for in the port.

When everything was pretty much "cast iron GM heads" guys were doing some crazy things to get to #1 on race day. Your best bet was to use as much common sense as you could to try and help the air out. But... you were always leaving hp on the table because while you were trying to figure it out.... somone had already done that 50 ports ago and were on to the 30th port revision. So I got to thinking about it and came to a conclusion..... my TIME is more valuable.

While I am good at putting engines together, I'm ten years behind the curve when compared to guys who port for a living. If I had cancer... I'd go to the cutting edge experts in that particular type of cancer. When I want to build the best engine... I go to the best porter I can afford.

Which brings me to my next point.
I understand that this is a hobby and so on... it is for me just like it is for many of you... but I refuse to spend lots of TIME and money investigating flow in cylinder heads with the appropriate equipment when I can be doing other things with my TIME.... which is the same thing as MONEY to me.

The only reason I can see for it, is when you just can't afford the expense of a professional job. Then again... how much is your time worth to you? Maybe your philosophy on TIME is directly related to a lack of funds.

One other thing... if you do have time and no money... you should at least invest some of that money in David Vizzard's book. I think that's probably the best place to start. Pay special attention to the stuff on bowl work. Great all 'round book though!

Disclaimer:
(General statements... not directed at anyone in particular)



-Mindgame

 

Yep,

One of the reasons I never got into head porting is exactly Mindgames points...

"I could see the port shape but I didn't know WHY some porting was different from others. I didn't know the seat angles used or how that effected the port. I didn't know what the valve sizes were or whether the valves had been moved or how that would need to be compensated for in the port."

The relationships from one thing to another is the KEY in engine building. Now when you go from how the SSR compares to the top cut of the valvejob, that's one more thing that I would have to understand exactly to get the results I'm looking for.

That's basically the key, what are you looking for? I'm looking for a port that works, makes awesome power and fits into the rest of my combination of parts.

"but I refuse to spend lots of TIME and money investigating flow in cylinder heads with the appropriate equipment when I can be doing other things with my TIME.... which is the same thing as MONEY to me."

This is one of the keys to basic economics... Time is Money. There is almost no way to gain the knowledge that comes with years of head porting with out that amount of time doing it. Even if you are doing R&D all the time on it, it's still going to take time to get there.

Bret

 

Some random thoughts on the subject.

1. Get Vizards book.
2. Figure out how you are going to judge your results.
3. You won't get it "right" the first time.
4. It won't be as good as a professional job.
5. You have to derive your own personal time/money equation and apply it intelligently.
6. Don't consider this unless you think you will enjoy the process, as opposed to just the results.
7. Get Vizards book.

I have never ported a set of heads. The whole process just doen't appeal to me. But my mechanical skills are fairly limited - I can use wrenchs and other basic hand tools. Can't fab stuff, weld, and that sort of thing. But I know many who can and they wouldn't consider porting their own heads. It's both and art and a science. The people who are good at it are not going to give you a detailed "how to", it's their livelihood. The Vizard book is about the only exception, but to some extent it still deals in generalities.

Rich

 

blah, blah, blah, people on this board must be rich and tight lipped. nobody cares to help people out by explaining some basics in head porting. most of us are not gunning to be the fastest guy in the country in our class, it's something we do for fun.

obviously, if you are competing seriously, you'll take your heads to get done by the best person you trust. most of us are not in that situation, but granted most of this board don't know jack about handgrinding. yes, it is an art.
but for those of us who use handgrinders on a regular basis building dies that make the panels of your vehicles, it would be nice to find some useful tips, port shapes, thin spots, valve guide shaping and so on.

if your building a budget car, it's only gonna help to grab a cartridge roll and smooth out the ports. i've found a polishing stone does wonders! keeps the grain in the right direction and makes polishing easier. i wish some head porters wouldn't be so tight lipped about basics. you wanna know why they charge so much? i'll tell you, because it's a PITA and takes many, many hours to do correctly. tricks of the trade for the highest flows are more for top end builds anyway, most of us really don't want top flow.

anyway, this is more of a rant than anything. i'm finishing my heads up, i plan to flow them to see what i end up with. it's gotta be better than stock, may not compete with AI, or LE but it cost me next to nothing to do. alot of the time i was at work keeping my EDM's going anyway, so i was still getting paid for my time. lol

why don't some experienced people actually stepup and say something usefull. yes, you can mess them up royally, but guess what, pride comes in things you have done yourself. i don't see how you people are so proud of cars you paid other people to do everything on... big whoop, you spent a ton of money and bolted it in, congrats your a simpleton.

rant...
mike

 

The basics have been covered here before, BY a couple of the good head porters.

 

Here is the "bible" we're talking about. It really does give you step-by-step head porting instructions, as well as "why", at least for the basics. If you follow Vizard's guidelines you have a fairly good chance of improving the flow.

http://www.themotorbookstore.com/che...der-heads.html

As long as we're ranting...I like to take pride in something I've done myself if it is well done. If I ported my own heads and my car slowed down (which it probably would), I wouldn't get much of a good buzz from that. Would you?
There are some things I just can't do myself as well as others can. I suggest that paying them a fair price for good work makes one the opposite of a simpleton.

I own a job shop and understand "government work". I hope your boss approves of doing the government work while tending to the EDMs. We're pretty lenient with employees, and help them out with personal projects with materials, design advice and use of the machines when they are off the clock, but I don't pay them to do their personal stuff on company time. I guess they are too busy making sure we make only good parts which our customers deserve and expect. If we are making injector bungs or supercharger drive parts my customers expect them to be spot on. Even with CNC controls, somebody needs to be checking.

End of MY rant.

Buy the book, Mike. It will help.

 

limige,

If you've been around this forum for a while then you know that your rant has been made before.

As I said one time before..... I'm a pretty good welder and I'm good at paying attention to details. I pay guys to do the stuff that I can't/won't and I feel no less pride in that than I do in anything else. In the end... I build the car. I don't make my own oil pans or valve covers or alot of other things I'm physically able to do because it'd cost me more to buy the materials and spend the time doing it.
We could argue "who's the bigger gearhead" all day long but we aren't talking on the level of say... throwing a new car at Lingenfelter and going to pick it up when it's done. Most of the guys here are true enthusiasts IMO.

-Mindgame

 

lol, i guess i was just in a mood, ace thanks for the link, i ordered it, i'll look it over to see if i wanna change anything i've done so far.
as far as on the clock stuff goes, my employer likes me to come in and check on the machines when we're really busy to make sure they burn through the night. i get paid 2 hrs showup whether i'm there for 5 minutes or 2 hrs. so i use that time to get some work done on my heads provided my machines are running. i could just go home but it gives me some time and if the machines stop, hey i'm there and can get them restarted. this has worked in the company's favor several nights when the wires broke while i was there. they are awesome about me working on my stuff. they ordered my steel for my sfc's and torque arm, as well as allowing me to work on my heads over the past year. i've made tools to check the endplay on a t56 as well as making my own wheel spacers and brake brackets to make an 8.5" rear work on my 4th gen.

i just wish i could afford to dump $1000 on the stage 3-4 job i'm doing myself to have someone else do it. but the fact is, a couple more dollars i could buy better castings the would outflow the ported ones. so why do it? bottom line is i'm scaping up money just to get it back on the road. i want to build a turbo motor next so i'm not really concerned with making this one get every last hp. as long as i'm better than stock i'm happy.

if you have the money, no doubt take them to someone. if not, and your concerned with messing up your heads then just take a sandpaper roll and smooth it all out.


on a side note, anyone know where to buy a graduated burat tube??? i don't know of any local lab supply stores, i'm thinking of using a syringe but unsure how well that's gonna come out. 1cc is equal to 1 ml right?

 

Correct, 1cc = 1mL.

What are you looking for a tube for, to measure the port volumes and stuff? I think I used a syringe too, when I did mine!

 

The reason I ported my own heads is kind of a two parter- 1) I don't have a whole lot of money, and 2) I like to tackle my own projects. Now I know full well that my port job will not come out like a pro, and for the "money" invested that's fine. I suppose I don't necesarily view my time as money because instead of messing around on the internet like now (basically doing nothing) I could be in the garage grinding on some heads. I also realize that skimping (as in me doing a project that I could let a pro do) will directly effect hitting my goals, and the slack will have to be picked up elsewhere. This is why I'm getting someone to match a cam to my heads. I don't know if I'll hit what I want, but I'm going to try to get all I can.

Interestingly enough I have learned a lot from porting this last set of heads. I have learned that it's fun to do, and fun to take pride in what you do. I've also learned that the pros are good at it for a reason- and that reason is they have put more time and effort into learning the ins and outs of it than I have or could do. Which is exactly why if I had more money I would pay someone who knows what they are doing to port some heads. And if I had a lot more money I'd buy some aftermarket castings then pay someone else to port them!