Custom LS1 Head Porting
12-31-2006, 03:19 PM
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Custom LS1 Head Porting I recently purchased heads/cam from a local area guy who got the heads from a company called Precision Motorsports.
After I purchased heads/cam I took them to my engine builder, to go through the heads/check the cam.
Upon inspecting the heads they found that the valves weren't seated correctly (up to 30% difference), they never lapped the valves in correctly and when completing the hand porting work they hit the bottom of a few valve guides, and they removed the vein out.
I am told there is a ledge or something in the intake pocket from the runner that is called a vein, that when the fuel comes in, it hits that, and atomizes, and when they removed that from the porting/polishing, it made the fuel "puddle" and you could see where it ran down inside.
My engine builder is very up on the new engines, but they mainly deal with older engines, so I am lookin for other opinions.
Did the guy who ported the heads messup by removing the vein?
Also can you give me a little more detail as to what it actually does/looks like?
After I purchased heads/cam I took them to my engine builder, to go through the heads/check the cam.
Upon inspecting the heads they found that the valves weren't seated correctly (up to 30% difference), they never lapped the valves in correctly and when completing the hand porting work they hit the bottom of a few valve guides, and they removed the vein out.
I am told there is a ledge or something in the intake pocket from the runner that is called a vein, that when the fuel comes in, it hits that, and atomizes, and when they removed that from the porting/polishing, it made the fuel "puddle" and you could see where it ran down inside.
My engine builder is very up on the new engines, but they mainly deal with older engines, so I am lookin for other opinions.
Did the guy who ported the heads messup by removing the vein?
Also can you give me a little more detail as to what it actually does/looks like?
01-01-2007, 07:01 AM
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PM mbp1..he is well versed on ls1/2 head porting oe email mbperformance@bigpond.com hope he can help you out
01-01-2007, 09:21 PM
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You should be able to tell if its been "puddling" by examining the shiny areas in the runner. Puddling dramatically affects low speed performance, return to idle etc..
Why is puddling bad?
The goal is to atomise all the fuel all the time, not let it puddle. Maintinaing atomisation by not slowing down airspeed is what separates the head porters. Fuel will not burn in liquid state - only when its atomised or in vapour or close enough to it.
To digress, it is easy to assume liquid fuels are inherently explosive because you light a match up to it and it goes *kaboom*. But its the vapour just off the surface which ignites, then quickly vaporises surrounding fuel in liquid state which burns and vaporises some more and so on. All this happens in nano-seconds creating the *illusion* the liquid fuel is *burning*, when infact it is an "cataclysmic" event of vaporisation.
Puddling is bad because fuel in liquid state cannot not burn or explode. Nothing can burn without oxygen. For fuel to burn, its needs to mix with oxygen, hence in a vapor state.
Why is puddling bad?
The goal is to atomise all the fuel all the time, not let it puddle. Maintinaing atomisation by not slowing down airspeed is what separates the head porters. Fuel will not burn in liquid state - only when its atomised or in vapour or close enough to it.
To digress, it is easy to assume liquid fuels are inherently explosive because you light a match up to it and it goes *kaboom*. But its the vapour just off the surface which ignites, then quickly vaporises surrounding fuel in liquid state which burns and vaporises some more and so on. All this happens in nano-seconds creating the *illusion* the liquid fuel is *burning*, when infact it is an "cataclysmic" event of vaporisation.
Puddling is bad because fuel in liquid state cannot not burn or explode. Nothing can burn without oxygen. For fuel to burn, its needs to mix with oxygen, hence in a vapor state.