Ok, going to show my stupidity. WTF do they really do when they do a 3,5,7,12 whatever angle valve job on a set of heads?

I need pitures or diagrams, I can not comprehend reading descriptions. I've read, and read, and I cant comprehend it.

Someone please draw me a diagram of WTF it changes please.

 

poor drawing. but, that's a cross-section of a port...cumbustion chamber is at the top. opening is where valve would sit. green line is 30 degrees. red line is 45 degrees (actually where valve seats/seals). blue line is 60*. that's a 3 angle valve job.

 

it's to smooth out the air's transition from the intake to teh combustion chamber. most stck angles are eithe r45* or 30* .

 

so basically, 3 is just cleaning up the edges really.

7/12 would be really hacking away at the head, and possibly cause seating problems with the valves then?

 

The valve and the valve seat have to be married together to seal properly- this is generally a 45* angle where the seat together.

If you were to start grinding away too much towards the outer (30*) and or inner (60*)edges of the seat then the valve would no longer seal down on to the seat when the valve is closed. The angle grinding is done as stated above to increase flow around the radius of the outer & inner seat edge AND the outer & inner valve edge to reduce seams and help increase flow through this area. The 45* width seating areas need to be left a sufficiant thickness for seating. I believe in most cases (I'm no expert though) that the 45* seat needs to retain about a .080 thickness.

 

Here ya go Jay. I did a quick scketch for you showing how the grinding basically radius' the sharp edges or seams and smoothes the flow through the vavle ports

 

I've also heard of 5 angle valve jobs & even radial cut valve jobs ( should be interesting for the vavle)

 

thanks, dean. much better drawing than i threw together! i can kinda understand a 5 angle job but i think 7 or 12(??) is a bit too much!

 

i tried a drawing, but i can't do that stuff on computers, but dean hit it right on the head and had a prety good drawing of what happens. it may help you understand if he lowers the valve to a opened position on the drawing and shows the airflow on there versus a head without the 3 angle valve job.

 

ok, I get it now

I have heard of 7angle. I think I heard once of a 12angle

 

well, i ahve done zero reading (other then this thread) on this topic, so heres a real newb question.

Q: how many angles are on the valve seats stock?

 

valve face is 45*, valve seat is 46*

 

soooo....how much power increases can you get from these???

 

you're not going to see any major power gains just by doing a 3 angle valve job or anything. if you do port work (properly) along with it and everything, you'll see a few extra horses, probably. its probably more a matter of, like, 5-10cfm.

 

One gains more effective air flow.
It's the combinations that "work together" to make the gains of "more power".
Look at a kitchen drain.
Put a strainer in the way. See what happens. Remove strainer & what happens?
Smooth the radius of the drain and what else happens?
Same thing going on in a cylinder head & the valves.
3 angle valve jobs are the "best" effective way to help make more power during a cylinder head rebuild. But it costs money, too.
Next best way to improve a cylinder head is undercut stems. One of my favorite "tricks" in cylinder head work choice.

 

Ah, I see. Thanks for the explanation guys.

 

Yep, You can see I drew them in in my picture above.

Some of these are the reasons why I am preaching to everyone about spending money on professionally ported heads from Supersix. You can request the options of valves in them.

When you simply port your own heads at home, you are not doing any valve work, no chamber work, nothing to the cc volume,
nothing to lighten the valve choice or harden them, nothing to the guides and seals, and they are not bench flowed for evenness and acurracy of potential output.

Airflow is everything. Everyone is debating right now on this Trueleo intake about it gaining poweron a stock motor. I do not denie that, its just a mistake to run a steel intake manifold for anything longer than drag racing- these are not drag racing motors, they favor endurance type use. The part that is not being addressed with the trueleo gain is that it is still bolted up to a tight bend intake port on the inherit defect design of the RWD cast iron 60*V6 head. This is the most restrictive part of a 60*v6 motor and needs to be addressed with professional help if you are going to see any sustantial gains. Supersix is the only company addressing these restricted intake ports all the way to the chamber and unshrouding the valves.