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  View original topic: ANOTHER head porting question **pics please** :)
hosspowerinc Tue Dec 12, 2006 6:56 pm

Well I just picked up a new set of 043's with a set of 40x35.5 valves and stock ports. Im doing the porting myself and have seen lots of pics but more is always better! Im more interested in how to keep the velocity up that just cutting big holes. Im sure thats "top secret" stuff but tips would be nice. I relaize that straightening out the port is #1 but what after that? Where to take more? Where to take less? Either I will be running a higher rpm 1914 or a lower rpm 2332. Ive done all the searching I can find on the subject but I still havent found that "heres how to port big hp heads" site yet :D Feel free to put a link up if youve found it! And feel free to flame me for being a newb on this :oops:

Muffler Mike Wed Dec 13, 2006 6:56 am

this is the only link i can think of. (assuming you havent seen it yet)
http://cal-look.com/tech/basic.shtml

Unfortunatly, most of the better head porters are not on line much if any.
but they do have a knack to be able to see flow, flow characteristics, air boundries, turbulence, etc.
i frequent Engine Machine Service and talk to Dick Nuss from time to time, and once in a while, we get onto the head subject again and he starts telling me things that go right over my head. I feel i am a fairly intelegent person when it comes to mechanics of what ever, but there is defintly an art to porting. Some of it defintly come from experience. Trial and error. Where and when to know when to remove or even god for bid, add in material. Completly change the shape or angle of the runner, change the volume, etc.

But dont let what i said discourage you. you may be one of those gifted people and not know it yet. trial and maybe error is the first step.

hosspowerinc Wed Dec 13, 2006 7:51 am

Thanks for the reply. I am familiar with the link but unfortunately its only a basic bowl blend and polish that they show. While Im not knocking the info because its great to get some extra power, Im just ready to step up to the next level.

Ive ported a few chevy heads with great results but they are a different ballgame. All you have to do is open them up to match a specific intake gasket. I wonder if any of you have some porting templates for the vw? Just something you could scan of the intake and exhaust design? And maybe some clarification between different designs. Ive seen the stock round port just enlarged, an oval shaped port, a D port, and a rectangular style. The latter 2 were both on welded heads and Im not ready to go that far just yet.

Also does the difference design mean more power in the low end or the topend? I know I have a million questions but answers to any would help out a lot!

RockNbus Wed Dec 13, 2006 8:55 am

Why don't you make or buy a flow bench? That way you will know what works. You could port some junk heads, flow check them, then grind some more and check them again until you achieve the desired flow rate. By using junk heads, if you take too much off, you can add J&B Weld as a correction. Once you get the junk head to flow the way you desire, you can replicate that port design to your good heads.

http://www.tractorsport.com/cgi-bin/forum/cgi-bin/ikonboard.cgi

hosspowerinc Wed Dec 13, 2006 10:23 am

Interesting.... I never knew you could build such a thing at home!

streetvwnorr Wed Dec 13, 2006 11:12 am

Maybe this will give you some guidance. Look under Portning. I built my self an flowbench and it as been a helpful tool.

http://www.streetvw.se/

Good luck!

//Markus

RockNbus Wed Dec 13, 2006 11:28 am

Good info Street. The pictures are great.

hosspowerinc Wed Dec 13, 2006 11:34 am

Yeah good stuff but how do you convert it to english!?!?

kcabtsaf Wed Dec 13, 2006 12:16 pm

http://babelfish.altavista.com/translate.dyn

madmike Wed Dec 13, 2006 12:29 pm

Hey Hosspower,look at my heads in the racing gallery good close up of the intakes but they are welded,you may want to have HOGGED super flows but unless u add some meat on them your gonna end up with a nice fluff&buff with the 40x35.5's,still better than stock 8) Madmike

Vayabroder Wed Dec 13, 2006 1:18 pm

Even though it's old school get yourself a copy of How to Hot Rod VW Engines; it has a whole section on porting VW heads with illustrations.

nsracing Wed Dec 13, 2006 8:05 pm

You have gotta be kidding, right?

You expect top secret head porters to just come out and spill the beans here? Come on now. We all know this ain't happenin'.

Read the How to HotRod VWs, Smokey U's Power Secrets, and few more head porting books. You are not going to get the info you need for the HP-making stuff.

At minimum you need access to porting tools, valve and seat grinder set up. If you got these, then all you need is book work and practice.

But you gotta get the theory down first of all.

steve34 Wed Dec 13, 2006 8:33 pm

I just did a set of 043s.

blend the intake seat shelf area to the seat.


put a slight (slight( ovale on the intake boss

polish the intakes and exhaust

that will get you where you want to be.

hosspowerinc Wed Dec 13, 2006 9:53 pm

nsracing wrote: You have gotta be kidding, right?

You expect top secret head porters to just come out and spill the beans here? Come on now. We all know this ain't happenin'.

One can dream cant they!?!? :lol: Seriously though, Ive seen some of your portwork and hope to accomplish something similar (but dont really plan on it!). Your template design is what what Id like to get my hands on! (I know, dreaming again!)

Honestly all I would like to achive is 150hp out of a 1915 but I want to know that I can do it again on another set of heads and understand what is going on in the port. The heads that you have pics of in the gallery, what hp numbers do they bring? And the way you have the guide boss blended instead of shaved on those is an absolute work of art!

As I said, Ive done porting before on small blocks and have done a basic bowl blend and polish on vw heads but the way vws flow is hard for me to see after working on chevy ports. To me the inside radius should be straighted the first 2/3 and then rounded out , the outside radius moved towards the valve and polished, and the guide boss blended. Am I far off on these ideas?

VW1300NORWAY Thu Dec 14, 2006 4:21 am

Here's a "Head-porting-page" made by Morten from Danmark :

http://www.gearheads.dk/portingside/

nsracing Thu Dec 14, 2006 6:33 am

VW1300NORWAY wrote: Here's a "Head-porting-page" made by Morten from Danmark :

http://www.gearheads.dk/portingside/

These chambers are all wrong above^^^^^. The VW is a "wedge-head" design. You do NOT lay back on opposite end of the spark plug. You can add material on the non-plug side..not remove. The plug side can be taken down some. If you need to create room in the chambers, do it on the plug side.

The "B-shape" chambers as in Autocrafts and CB Elim heads, Super Flos have been proven to produce some serious HP. Try NOT do deviate farther than that, unless you have a testing facility with lots of machines.

Unshouding is also not done that much above. You can read How To HotRod VWs and you can see a chamber like that losing airspeed. Bill Fisher even shows you how far you can go with the unshrouding.

Start with the Bill Fisher book and go from there.

The templates are more for matching the manifolds than porting. (Both actually). I make them for several heads. CB 044s, Stock 040/043.


KROC Fri Dec 15, 2006 9:49 am

nsracing wrote: VW1300NORWAY wrote: Here's a "Head-porting-page" made by Morten from Danmark :

http://www.gearheads.dk/portingside/

These chambers are all wrong above^^^^^. The VW is a "wedge-head" design. You do NOT lay back on opposite end of the spark plug. You can add material on the non-plug side..not remove. The plug side can be taken down some. If you need to create room in the chambers, do it on the plug side.

The "B-shape" chambers as in Autocrafts and CB Elim heads, Super Flos have been proven to produce some serious HP. Try NOT do deviate farther than that, unless you have a testing facility with lots of machines.

Unshouding is also not done that much above. You can read How To HotRod VWs and you can see a chamber like that losing airspeed. Bill Fisher even shows you how far you can go with the unshrouding.



Hi I am wondering what you are basing your theory on as to why you can not Lay back on the opposite side of the spark plug? The reason why I ask is because in a 60 cc chamber I have seen significant improvement in Wet flow characteristics on a Mondello wet flow bench sucking at 60" and backed this up with very good performance gains. I do not remove a ton from this side but Ido remove some material. The most important thing to remember is to try not to have any Flat areas on the floor of your chamber if possible.

I agree that the B chambers are the best and work very well with little unshrouding if the chamber is 35cc or less, However with street chamber volumes these also respond to some unshrouding as long as it is not taken to far and destroy the pressure recovery.

Thanks.

nsracing Fri Dec 15, 2006 12:01 pm

If it is a wedge head...let it remain a wedge head. The idea of it is that..as the fuel charge compresses, it gets pushed over to the sparkplug -the majority of the fuel charge. The flame front will be hottest closest to the spark. If you lay back opposite the plug, all you are doing is moving the fuel charge that much farther away from the flame front.

Think of it this way...you only have so many degrees to burn all the fuel charge. If you get it out farther to reach....you could be losing HP.

It is not just flow of air that you worry about when you reconfigure the chamber. You have to account for the squish and flame front to position of plug in relation to the seats/valves....especially flame front.

True Hemi heads have centralized spark plugs ..right in the middle. Wedge heads have it on the one end with the largest portion of the fuel air/fuel charge.

How is that?



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