Head gurus: Seat angle ?
 

Has anyone doing head work experimented with seat angles?

I see the spec calls for a 30/45/75. Has anyone tried a 30/45/60 with success? How about any other cuts for a 3.0 street engine?

Mike

the bottom cut doesn't make much difference if it's 60 or 75. if you use a stone, the 75 tends to wedge. i use a 60° hand cutter so i can remove metal where i want instead of where the stone wants. a lot of times when you do the final lower cut, there is perfect seat width on one side and too wide on the other. the stone tends to follow the hole and remove material from the perfect side while grinding on the wide side. a single blade hand cutter doesn't do that.

Thanks for the reply John, after looking at the head with my machinist, it makes sense the way you describe. Do you blend the cut back into the bowl or leave it "as is"

If you really want to massage them after the 60 deg or what ever you elect you can blend it all togather b4 and after your seat (carefull not to scew up your seat)....In my case it really has turned it loose.
The other thing I do is polish the back of the intake valve to high luster.......for that mater do the whole combution chamber.(Less burs less knock)...Thats how i do mine, works4me

I'll be breaking out the die grinder and the dremel this weekend. Will try to post some before and after shots. Thanks for the replies!

Mike

if you put prussion blue or grease on the valve seat (the 45) then drop it into the correct hole( dont change them around) you will more ezly see the aera to work on after you remove the valve,,,as the seat aera in the head is pretty narrow.

Your nuts.

Christian

Are you using stones or cutters on the seats? Do you use Sioux stones, Sunnen or K-Line products, what product line are you using?

I grind the seat angles using a Kwik Way wet valve grinding system. it has a pilot that inserts into the guide so the seats get ground concentric with the guide angle. It floods the seat while grinding with lubricant and the seats come put perfectly.

Grinding vs. cutting has advantages since grinding removes tenths, while cutting removes thousandths. Also cutting the seats rips the material off, while grinding burnishes the surface and can give a more stable finish if sdone properly.

"Your nuts."


Relax - I know better than to attack the seats with the carbide cutter and sanding rolls. I'll let my machinist do that with his Serdi machine.:D

Mike:

who ever said use anything but stones??? but if do not want to see what is goinng on that your deal....
and if you want to clean up the ports and polish stuff you will need a whole array of stuff .
And Mike you do not have to call anyone nuts just cause you own a machine shop.... or disagree with them we are tring to move our selfs up a notch or to here...no regressions

huh?

Afterburn,

I think Christian meant I am nuts for saying I was going to break out the die grinder! I appreciate your comments and plan to do some work around the bowls and let my machinist do the finish work on the seats.

Mike

My bad, I misunderstood, I thought he was going to try and change his valve seat angles by hand using a die grinder, thats what I thought was nuts. You dont need a machine shop to do port work, I wasnt implying that. Sorry if it came out worng.

your sins are forgiven:)