Inlet valve seat insert mismatch

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Biancorally
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Joined: July 9th, 2011, 2:30 pm
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Inlet valve seat insert mismatch

Post by Biancorally »

Hello Guy,

i own a Fiat coupe 16v cylinder head which I like to use later for a conversion on my strada.

During disassembly I noticed that the inlet valve seat inserts had a big mismatch, about 1 mm step.

My question is, is it possible to open the throat by 2mm to eliminate this mismatch? I guess opening the throat by 2 mm results in a loss of gas velocity?

Guy, you said, opening the throat 0.5 mm gives no gain in terms of flow for this valve size!

Suggestions greatly appreciated.

Regards

Daniel
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Inlet valve seat insert mismatch
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Guy Croft
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Re: Inlet valve seat insert mismatch

Post by Guy Croft »

That's called an undercut - in this case leave it alone, generally you should not increase the throat bore - you might find there is no metal left for the valve contact face. A purely practical perspective. What influence on flow? Dunno.

G
Biancorally
Posts: 50
Joined: July 9th, 2011, 2:30 pm
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Re: Inlet valve seat insert mismatch

Post by Biancorally »

Thank you very much, Guy. I'll leave it like that.
I will remember the technical word "undercut", thanks.

Daniel
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