Valvetrain experts... Question.
Thread Starter
Team Owner
Joined: Jun 2004
Posts: 20,216
Likes: 4
From: Smile, it's just the internet.
Valvetrain experts... Question.
Just out of curiosity...
Regarding the three-angle geometry of the standard valve grind...
Why not a smooth radius after the seat chamfer? Does anybody do this?
I understand the need for the flat seat, but why the secondary angles? It seems to me that a radius would offer better flow.
Regarding the three-angle geometry of the standard valve grind...
Why not a smooth radius after the seat chamfer? Does anybody do this?
I understand the need for the flat seat, but why the secondary angles? It seems to me that a radius would offer better flow.
Team Owner
Joined: Sep 2003
Posts: 88,393
Likes: 2
From: eville in
some VARY high end engines do on some parts of the valve.. i think the diff. is super minor, compaired to cost.... i've read that a air/fuel mixture
like's a 7 deg. change in direction... i have put 5 on the vavle and on the seat before...... but i did it and wasn't paying for it
i don't know if i got any over a 3 angle
like's a 7 deg. change in direction... i have put 5 on the vavle and on the seat before...... but i did it and wasn't paying for it
i don't know if i got any over a 3 angle
Race Director
Joined: Dec 1999
Posts: 16,945
Likes: 9
Stock doesn't have a 3 angle valve job. As for why the angles, because it's for icnreasing the flow at low lift, there those andlges flow better than a radius. It's not about what looks to be right but what proves on the flowbench.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
yes, They are Manley race flow and pro flow valves. I have only ran these type of valves on every head for the past 15 or so years. the stem is also tapered to not impead port flow.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,502
From: Little Rock AR
"Venturi" valve seats are $$$ for little gain. The three angle valve job is...well....3 angles. 
The middle cut is the seat, the outer cut and inner cut form the "width" of the seat. Thinner seats are better for flow, wider seats are better for durabillity.
-Mark.
The middle cut is the seat, the outer cut and inner cut form the "width" of the seat. Thinner seats are better for flow, wider seats are better for durabillity.
-Mark.
