Tractorsport Flowbench Forum Archive

by **coulterracn** » Sun Sep 27, 2009 11:53 pm

Yes there is some CSA figuring in the bowl area. You may need to de bowl and give a barrel shape to the bowl to get the CSA needed to eliminate any choke in the throat. I think I remember seeing a picture or your intake bowl posted elsewhere on this forum. The bowl is a shallow bowl and would benefit from the barrel shape.

I don't remember what your air velocity measured at the ssr or if you posted it elsewhere. I would concentrate on a good radius off the seat throat angle for now.

Ray

by **jfholm** » Mon Sep 28, 2009 12:01 pm

[color=#000000]Tom,
Depending on RPM and port configuration the throat area right under the valve is usually 88% to 90% of the valve diameter. Some ports can use more and some need less. For real high rpm on the 23

by **200cfm** » Mon Sep 28, 2009 10:59 pm

Ok, by bigger radius I think you mean a longer radius. Will try that. I was not sure just where the radius should end. It sort of currently ends at a point followed by a vertical drop to the 60 cut. Sort of the way Gordons SSR looks in his above photo. Yes, I got your email, thanks.

So much to learn, so little time.

by **Flash** » Thu Oct 01, 2009 10:33 am

the smallest "csa" of a port is called the choke......right?
And the choke should be as close to the valve seat as you can get it.......right?

so with my previous porting, my bowl is way to large, to be the choke area. and the choke "rpm" is already to high............

Do I cut my mold up to fined the choke csa and.... port around it????? Or do i port it to push the choke csa, closer to the seat!...?

I ask this becouse i have seen some 340/360 LA heads (aka X and J heads) were that big dog leg, or guide boss, is completly remove.........so i know now that i can chase the choke csa back to valve area...................but do i want too! even a little bit??????????

all appinion are incurage

Thanks in advace.

by **Malvin** » Sat Oct 03, 2009 12:54 am

Flash here is a picture of the bowl & guide before any port work

by **Malvin** » Sat Oct 03, 2009 12:57 am

Here is the same one with bowl & guide work

by **Malvin** » Sat Oct 03, 2009 1:01 am

Flash I do have the head that I did do a cuply of slice sections
that I can post the pictures of in my next post.

Malvin

by **Malvin** » Sat Oct 03, 2009 1:14 am

Flash here are some pictures that the head has been cut into
section

by **Malvin** » Sat Oct 03, 2009 1:16 am

flash here is more

by **Malvin** » Sat Oct 03, 2009 1:17 am

Flash one more of the Exhaust

by **Flash** » Sat Oct 03, 2009 1:36 am

Malvin, so what did you use these head on and how did they perform?

Thanks for the pictures, shows me there is a lot of metal on the intake ssr before i would find water.

Will be referring back to these pictures many times. :;):

EDIT: These are test head you cut up and then ported, not head you will be installing on to any thing........."I'm a little slow..........But I sure am not fast'!!! :laugh:

by **Flash** » Sat Oct 03, 2009 2:39 am

Cut up my mold today and drew it on paper then counted up the squares.................I though i knew what CSA is but now I'm confused.

If i count up all the squares...... i have from 7.5" to 9"

Well that set up some crazy numbers with Pipe Max...........

so is the CSA just a straight measure a crossed the surface?
I had this discussion with some on here but can't find it now.

by **Malvin** » Sat Oct 03, 2009 2:41 am

Flash wrote:[QUOTE Malvin, so what did you use these head on and how did they perform?[/quote]

This heads was on a 360/ 408 stroked Sbm they did perform really good but they got to thin on the left side & right side at the ssr on the wall coming down to the floor thats were they ended up cracking so we pulled the heads off to start over.
I will see if I can get some better pictures up of the roof &
the long side of the runner for you I will try to put little arrows to the areas that I am tying to show were it has been ported OK?

Malvin

by **Malvin** » Sat Oct 03, 2009 3:00 am

Flash here is more pictures

by **Malvin** » Sat Oct 03, 2009 3:02 am

here is some more Flash

Tractorsport Flowbench Forum Archive

Porting a Chy 340/360 head.

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