portning af toppe

hejsa der er problemer med dette link nogen der kan hjælpe mig
http://www.gearheads.dk/portingside/porting.htm

I port my own heads, it is not brain surgury you know..

The pros can maybe get 10-20% more flow out of the heads than you can by yourself, but it is really great fun, and much cheaper to try it out yourself.
And even a simple porting job gives a big result...

So come on, get your grinder out of the closet.....

Regarding valves:
Standard 35,5-32 valves in a decent portet head will work to more than 100hp
40-35,5 valves (044) can flow to more than 150hp.

Valves that are too big can even hurt the flow...!

I will prefer a nicely ported head with "small" valves compared to a unported head with big valves anytime..

This is a bunch of pictures that describes how I usually port the heads on my own engines. This is what can be done with only basic tools and lot of patience.!
Remember to wear protective glasses and earprotection!
Click on the thumbnails to get the " big picture"........;-)
Questions? Comments?...here!

This is what I started with, a standard 040 casting converted to 40mm and 35,5 stainless valves. The head has been flycut to match 94mm cylinders, to be used on my "Oxyboxer engine" see the projekt here
I started with disassembling of the head, by removing the valves. I have a special vw-tool for this task, but you could use any valvespring compressor..
This is the inlet port of the standard head, ...like a virgin...
Questions? Comments?...here
and the exhaust ports... Questions? Comments?...here!
this is from the combustionchamber side, you can clearly see the rough edges where the machined areas meets the cast areas..
closeup
and again, is would be a sin, not to touch these poor flowing ports...
I start by spraypainting the chamberside, and the gasket surfaces on the inlet and exhaustside..

Then I stick a cylinder in the head so I can scribe a line where the edge of the sealing surface is..
Here you can see the line...
Then i scribe a line 13mm out from the radius of the valves
And a line to "tie" them together. this is the edge of my new combustion chamber. What I am going to do here is normally called "unshrouding the valves", and to my opinion, -is just as important as porting the ports before the valves
Put the head in a vise to hold it firmly.
this is my favorite porting tools: an air grinder with different shapes of grinders. The oval one in the grinder is my favorite. You could probably also use a Dremel tool, but i have never tried it..
The metal gaskets is what i use for making templates of, the thick paper gasket is what I will use when the engine is finished.
Another important tool is a can of WD40 to spray on the grinders from time to time to prevent the aluminiun to burn on to the tools
Here the unschrouding is roughly finished, I use a set of dummy valves in the head while I am working, to protect the seats
Questions? Comments?...here!
You can end the job by polishing the surface, I probably should have too, but I did not have the patience (and I dont think it matters that much)
Then the inlet ports. The objektive is to "straighten" the port, to make it more easy for the air/fuel to flow through the port. there is quite a bit wich needs to be removed above the valveguide, compare this picture to the pictures of the "unported" head above
Use your finger again and again to feel where the edges are, and to compare that you get all the ports identically
Now there is "light at the end of the tunnel"...!
Just for comparison..
Remember these ports are going on a 2110cc engine, If you are going to build a much smaller engine, you probably should not make the ports this big (unless it is going to make high rpms!)
beware of the "hump" below the valvesprings, it is a thin area, dont take too much off there..
When the porting of the first inlet port was done, I made a template of a original metal inlet gasket, witch i matched the hole , and used to scribe how the other three ports should be ported.
I have saved the template/gasket for my next portingjob...
On the echaustports, i simply enlarged the hole in a echaust gasket to a diameter of 36mm, and used that as a template for alle the exhaustports.
You should match the exhaustport to the size of your exhaustsystem...
A picture of the "before" port..
Here you can see the sharp corner(s) in the port. especially on the "short" side just below the seat..
Here you can see how i have "widened" the port, and radiused the "short" side
another pic.

There is a huge difference before and after you have radiused the short side, amazing that the exhaust can get out without this work done...
Even the factory found out, and did it on the wbx heads !
here my "opened" exhaust port...
This is a tough one, you purists close your eyes..., -a poor mans 3 angle valvejob...
The pictures speaks for themselves.. Questions? Comments?...here!
before and after...
much better flow at low lift.......
finally a lapping job...and done..
Remember to matchport the manifolds too!!

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om det passer aner jeg ikke , tog bare en vopy paste , har ikke selv læst det

ja men forældede link har det med at gå i kludder , især hvis der er billeder på..

internettet er desværre sjældent et sted hvor ting kan gemmes for tid og evighed