OST-017: Ed Sullivan it ain't!

[oldeskewltoy]

from another forum Wrote:Dan, how do you know how large to go? I have first hand experience with over-porting...

In this case....I'm going on how much material I've seen removed by Loynings, and a few other 4AG porters to go by


One of the reasons I've stuck to mostly street heads has been how much knowledge I bring to the job. Its one thing to free up 3 to 10 hp - depending on how crappy a casting I'm working. Its a far different thing to take those gains, and stretch them to a fully worked race head.

[totta Crolla]

I have always been interested in modifying heads for N/A applications
but I have yet to find a cost effective flowbench to quantify the results with.
Which flowbench are you using OST ?

[Bean]

totta Crolla Wrote:I have always been interested in modifying heads for N/A applications
but I have yet to find a cost effective flowbench to quantify the results with.
Which flowbench are you using OST ?

If I remember correctly he got one of these: http://www.flowperformance.com/price.html

[oldeskewltoy]

DON'T use it!!!! The people @ Flow Performance have not been very helpful. All in all, I spent about $1600 building mine... and I've had a problem getting it calibrated because their use instructions are SOOOOOO horrible. If you understand the actual math involved, you might find the Flow Performance unit fine, but the tech writing for their servicing and diagnosis of issues sucks balls


I recommend joining this group of people - http://www.flowbenchtech.com/forum/ I'm pretty sure the forums owner has a similar flowbench kit to the one from Flow Performance.


Here is what I built... semi-portable to allow me to store it away(basement), or pull it out to use(garage).



The vacuum fits under the computer, alongside the unit The rolling rack is a commercial grade bakers rack.

[oldeskewltoy]

Now that the intake side has been pushed out to where it'll need to be, the exhaust side work begins.



Here is the partially worked head(by previous porter) prior to my work. You can see some port work has been done.




Again since the O/S valve seats have not as yet been installed, the bowl work is not the main attraction. Here are the views of the before and after port work.



You can see much more, the port is now very smooth, and it now has the proper shape.


What do I mean when I say proper shape???



'nuff said.


More to come

[BOOMEX]

Great work as you alwase do...

[oldeskewltoy]

BOOMEX Wrote:Great work as you alwase do...

thank you for the kind comment........ :mrgreen:



Ext port #2. In this one note it appears to be a an overall port mismatch(size)...




check again... the guide spacing is less than 1/2mm different, the port size difference is pushing the stock port(29.5 to 30.5) out to 32.5mm... or just shy of the stock gaskets 33mm diameter. The port roof, and left hand wall required the most change - about 3mm in width, and 2.5mm in height

[oldeskewltoy]

from another forum Wrote:Hey Dan, what is making you settle on 33mm exhaust port opening? I have some software telling me that 34 or even 35mm is ideal for an aggressive 20V build. I would think a race head would want at least that much exhaust port?

oldeskewltoy Wrote:In this case....I'm going on how much material I've seen removed by Loynings,

Somewhat more to the point..... What shape is the exhaust port in your software, not the opening, but the port itself? Are your ports "Y" shaped? Or "V" shaped?




Imagine if you will you have sliced the head in half. The 2 halves are lower and upper. The "Y" you see above is the shape of a standard 4AGE port as viewed from above. The "V" shape is more of what I do..... I change the taper - photo is not exact, but shows the essence of what I do on the exhaust side

At the edge - the port is 33mm, but because of the taper the port is graduated all the way back to the bowl

[oldeskewltoy]

I decided for posting exhaust ports #3 and #4 I would use the gasket to help show just how significant the change actually is....



Port #3 above shows a before and after of the exhaust.

In each of the three ports I've shown, they reveal quite a bit... but it is sometimes tough to show just how much I actually change the port....... So while porting #4, I stumbled across what I thought to be a very effective way.....

Below is a slightly different multi-panel view of #4 exhaust port, this view is how I look @ the port while doing the most significant work... with the head upside down



:eek: Quite a bit of material removed... wouldn't you say????

And that isn't a collection of material from all the ports, that is just the material removed from port #4 :eek:

oldeskewltoy Wrote:

'nuff said.

TIMES 4




More to come

[oldeskewltoy]

Quote:The 4 intake ports are now mostly to size

Wow......

In all of the heads I've done to this point I've NEVER spent 1/4 as much time on the intake side as I have on this head. I've easily spent 24+ hours on the intake side ALONE!

oldeskewltoy Wrote:The cross width of a standard smallport is about 44-46mm, the cross width of these ports is now between 48mm, and 48.25mm

The port widths are now all between 49.25mm and 49.40mm

Below is port #4 - remember... this head had been to another head porter previously, so the top view isn't stock... but how I got it from that porter....



The middle view was taken 10 days ago, when I moved from the intake side to the exhaust side.

The bottom view is the most recent, and the ports (still not the bowls) are just about finished, there is a small shadow line(seen through right hand bowl in lower view) that I'll look more carefully at, and I might do a bit more blending there... The bowls have received some attention with quite a bit of material coming out of the bowl walls, and the splitters.