How do you CC an intake port??
Thread Starter
Racer
Joined: Sep 2003
Posts: 420
Likes: 1
From: Indianapolis IN
How do you CC an intake port??
Do you do it with the valve in place or is there another way? I know the valve stem takes up some room so I'm not sure if the intake port volume includes the valve and stem.
With my 2.25 valve in place it takes up 252cc. Yeah, I know that valve may be a little overkill with oval ports, but they're there.
With my 2.25 valve in place it takes up 252cc. Yeah, I know that valve may be a little overkill with oval ports, but they're there.
Le Mans Master
Joined: Aug 2000
Posts: 6,362
Likes: 7
From: Brazos TX
Cruise-In IV Veteran
Cruise-In V Veteran
Re: How do you CC an intake port?? (blunsford)
CC it with the valve installed. You are really just comparing port to port to equalize things. Obviously you want the maximun amount of flow with the smallest port possible.
Thread Starter
Racer
Joined: Sep 2003
Posts: 420
Likes: 1
From: Indianapolis IN
Re: How do you CC an intake port?? (burners)
I'm trying to figure out what size the intake runners are - not if they're uniform. I've already done that.
I assume you subtract the size of the valve stem when sizing the intake runner???? About how much to I add to the intake runner size to take into account the valve?
I assume you subtract the size of the valve stem when sizing the intake runner???? About how much to I add to the intake runner size to take into account the valve?
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: How do you CC an intake port?? (blunsford)
I assume you subtract the size of the valve stem when sizing the intake runner???? About how much to I add to the intake runner size to take into account the valve?
[Modified by Pete79L82, 7:55 PM 11/20/2003]
Thread Starter
Racer
Joined: Sep 2003
Posts: 420
Likes: 1
From: Indianapolis IN
Re: How do you CC an intake port?? (Red69)
RED69 - The runner is the "tube" that runs inside of the cylinder head from the intake manifold to the intake valve and from the exhaust valve to the exhaust manifold. The only stupid question is the one that's not asked.
Now, I agree that that is the way to determine the usable runner size. But I wonder if when Edelbrock or anyone else advertises their runner size if they include the valve. That means that a simple valve change would change the runner volume.
Now, I agree that that is the way to determine the usable runner size. But I wonder if when Edelbrock or anyone else advertises their runner size if they include the valve. That means that a simple valve change would change the runner volume.
Drifting
Joined: Oct 2000
Posts: 1,825
Likes: 56
From: Shawano WI
Re: How do you CC an intake port?? (blunsford)
I am not sure about Edelbrock, but I do know the top quality head manufactures like Dart, Brodix, GM, World use advertsed numbers that are with a valve in place. Because they are castings the volume from port to port will change but in general they will be within 1 or 2 cc's of advertised. Advertised numbers are an average of all the ports on the head.
If you do not want the valve included then you have to cc the port "backwards", meaning that you will fill the runner from the bowl rather than the intake face. Make a blockoff plate for the intake face of the runner, use a heavy grease to seal the valve guide and fill the runner from the bowl area just up to the 45 degree valve seat. That will give you the maximum cc volume. Do all four ports on the head to come to an average volume.
Pete
[Modified by Pete79L82, 7:01 AM 11/21/2003]
If you do not want the valve included then you have to cc the port "backwards", meaning that you will fill the runner from the bowl rather than the intake face. Make a blockoff plate for the intake face of the runner, use a heavy grease to seal the valve guide and fill the runner from the bowl area just up to the 45 degree valve seat. That will give you the maximum cc volume. Do all four ports on the head to come to an average volume.
Pete
[Modified by Pete79L82, 7:01 AM 11/21/2003]
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