ok, im a newbie on flatheads so be gentle, doing a valve job on my 49 engine, hit the seats with a 45 first, then blued the valve, it hits the valve at the top of the valve, a little to close for me, so hit it with a 30, and no change, a guy told me to do 30,60,then 45, still the same, seems like i just cant get it down on the center of the valve, have done several valve jobs on overheads and never had this problem, am i overlooking something?
I got to ask; Why would he suggest a 3 angle if you are already out to high? Get a vernier and measure the ID of the seat to compare with the valve you have. You need to be cutting the outermost part of the seat to bring it to more center...but check that ID first in case someone hogged it out for more flow?
If the seat is to high on the valve keep going with the 30 until you have a margin on top. Then narrow it up from the bottom with the 60. You want to keep your stones in good shape, true them often and they cut better. I use 1/2 degree more on the valve to keep the upper margin crisp. The guy that told you 30 60 45 knows what he is talking about. You don't sink the valves as much that way. You hit it with the 30 intil you have the 30 touching the original seat at it's lowest point, use the 60 till you hit the seat at the lowest point (you may not have half a seat but that's from the guide not being lined up with the seat) then grind with the 45 intill all the pits are gone and you have a good clean seat. Then you check it with bluing and narrow it up. I've done it this way since dear old dad taught me when I was 11 years old and it works for me. Hope this helps Jeff
Like Dyce said. Usin' 45' on the seat and 44 1/2' on the valve makes things easier to see and everything seals instantly. I use a wide Sharpie marker in stead of machinist dye. Smokey
thanks for the imput guys, ill finish the seats today, then start putting it back together, let you know how things turn out!
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