Why not radius the valve and seat?

fiveohpatrol · 07-02-2002, 12:58 PM

I've heard of 3 and 5 angle valve jobs and such, but I was just thinking, why not put a smooth radius on the valve and a matching one on the valve seat?
In my head, it seems like the air would flow better over a smooth radius than 3 or 5 sharp angles.
Has this ever been tried? It might be a bit of a headache making the tooling to do it, but I'd think for a serious race motor that it would probably be well worth it. Then again, maybe it would be worse. Just another case of me thinking up stupid ideas

PKRWUD · 07-02-2002, 02:33 PM

Great idea, except that the valve needs a more defined seat to help keep it from "wondering" side to side, wearing out the guides prematurely.

Take care,
-Chris

Ieatcamaros · 07-02-2002, 05:50 PM

PKRWUD is right. If the valve had a radius for a seat, it would definitely wear out prematurely. That is the purpose of a multiple angle valve job, to have a more defined seat. I think this is right, but don't take it to the bank. I could see it helping airflow a little. Anyway, nothing wrong with your idea. But a radius will wear out the guides quicker than the multiple angle seat.

fiveohpatrol · 07-02-2002, 08:26 PM

easy fix: Titanium valve guides

if it is used on a race only motor that is rebuilt every so often then I would think that it wouldnt be much of a problem. But oh well

nickj8685 · 07-02-2002, 09:11 PM

MM&FF has a discusion on this very thing.
This is what they said:" For short cammed motors, radius the fornt face of both the inlet and exhuast but for long cams(over 280 seat duration) only do the exhaust. Both valves should be back-cut 30 degrees to leave a seat on the valve about 20 thousandths wider than the seat in the heads."

07-02-2002, 12:58 PM	#1
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	Why not radius the valve and seat? I've heard of 3 and 5 angle valve jobs and such, but I was just thinking, why not put a smooth radius on the valve and a matching one on the valve seat? In my head, it seems like the air would flow better over a smooth radius than 3 or 5 sharp angles. Has this ever been tried? It might be a bit of a headache making the tooling to do it, but I'd think for a serious race motor that it would probably be well worth it. Then again, maybe it would be worse. Just another case of me thinking up stupid ideas __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

07-02-2002, 02:33 PM	#2
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Great idea, except that the valve needs a more defined seat to help keep it from "wondering" side to side, wearing out the guides prematurely. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

07-02-2002, 05:50 PM	#3
Ieatcamaros Domestic Rice really sucks! Join Date: Apr 2002 Location: KY Posts: 973	PKRWUD is right. If the valve had a radius for a seat, it would definitely wear out prematurely. That is the purpose of a multiple angle valve job, to have a more defined seat. I think this is right, but don't take it to the bank. I could see it helping airflow a little. Anyway, nothing wrong with your idea. But a radius will wear out the guides quicker than the multiple angle seat. __________________ The sig says it all.

07-02-2002, 08:26 PM	#4
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	easy fix: Titanium valve guides if it is used on a race only motor that is rebuilt every so often then I would think that it wouldnt be much of a problem. But oh well __________________ NMRA O/C 9516 NA pumpgas stickshift 347 10.65@125.6, 6.73@100, 1.41 60ft

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07-02-2002, 09:11 PM	#5
nickj8685 Registered Member Join Date: Jul 2002 Location: Russellville MO, where men are men and sheep are scared Posts: 66	MM&FF has a discusion on this very thing. This is what they said:" For short cammed motors, radius the fornt face of both the inlet and exhuast but for long cams(over 280 seat duration) only do the exhaust. Both valves should be back-cut 30 degrees to leave a seat on the valve about 20 thousandths wider than the seat in the heads."