Run out on valves

Larry Hill · 12-21-2023, 10:19 AM

You would prefer the needle on the indicator not move. Less than .0005”

Alan Roehrich · 12-21-2023, 12:51 PM

Larry is correct. You have to be careful, it may take a couple of tries to get the valve true in the grinder chuck, especially on older grinders. The new ball style chucks are more accurate.

Larry Hill · 12-22-2023, 08:57 PM

I check the run out in a R8 collet after I checked the runout on the ID of the spindle. Most things are not as good as advertised. I trust but verify. I have a lot of stuff that are “good parts” but just not good enough to race.

Dave Noll · 12-23-2023, 02:13 AM

Question: it's not a big deal but it's nagging at me. I understand why an egg shaped valve head ( 2 high spots showing on the indicator in 1 rotation) would be bad. But why would a valve head not concentric to the valve stem by .0015 be a problem if the valve stem has .003 clearance to the guide?

Adger Smith · 12-23-2023, 12:18 PM

Go ahead and split hairs.
Then TQ the head down and distort everything.
I bet very few use a TQ plate doing the seats.

Dwight Southerland · 12-24-2023, 02:14 PM

Quote:

Originally Posted by Dave Noll

Question: it's not a big deal but it's nagging at me. I understand why an egg shaped valve head ( 2 high spots showing on the indicator in 1 rotation) would be bad. But why would a valve head not concentric to the valve stem by .0015 be a problem if the valve stem has .003 clearance to the guide?

.003 clearance on the guide does not equate to .003 movement at the head. Stick your valve in the guide with oil on it and see if you can measure how much movement it has at the seat level. The length of the guide, the diameter of the stem and the distance from the guide to the seat all play into the stability of the valve. I would be surprised if it is a measurable amount with a dial indicator.

SpeierRacing · 12-25-2023, 06:21 PM

I don't know anything I would run .003 guide clearance on! Most 11/32 intakes should be .0010-.0012 and exhaust .0013ish. 5/16 and under well under .0010..

People ask me all the time what is acceptable seat run out. Whatever your guide clearance is! .0000 is cool but doesn't matter in the grand scheme of things!

12-21-2023, 10:19 AM	#1
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,662 Likes: 1,953 Liked 10,820 Times in 2,249 Posts	Re: Run out on valves You would prefer the needle on the indicator not move. Less than .0005” __________________ IHM Used Parts https://ihmusedparts.com 888-821-1817

12-21-2023, 12:51 PM	#2
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,124 Likes: 1,581 Liked 1,879 Times in 422 Posts	Re: Run out on valves Larry is correct. You have to be careful, it may take a couple of tries to get the valve true in the grinder chuck, especially on older grinders. The new ball style chucks are more accurate. __________________ Alan Roehrich 212A G/S

12-22-2023, 08:57 PM	#3
Larry Hill Live Reporter Join Date: Oct 2004 Location: Hickory, Ky Posts: 10,662 Likes: 1,953 Liked 10,820 Times in 2,249 Posts	Re: Run out on valves I check the run out in a R8 collet after I checked the runout on the ID of the spindle. Most things are not as good as advertised. I trust but verify. I have a lot of stuff that are “good parts” but just not good enough to race. __________________ IHM Used Parts https://ihmusedparts.com 888-821-1817

12-23-2023, 02:13 AM	#4
Dave Noll Senior Member Join Date: Nov 2007 Location: Div. 6, Eastern, WA Posts: 710 Likes: 2,681 Liked 240 Times in 112 Posts	Re: Run out on valves Question: it's not a big deal but it's nagging at me. I understand why an egg shaped valve head ( 2 high spots showing on the indicator in 1 rotation) would be bad. But why would a valve head not concentric to the valve stem by .0015 be a problem if the valve stem has .003 clearance to the guide? __________________ Dave Noll, EF/S ,?/SA 6526

12-23-2023, 12:18 PM	#5
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Run out on valves Go ahead and split hairs. Then TQ the head down and distort everything. I bet very few use a TQ plate doing the seats. __________________ Adger Smith (Former SS)

12-25-2023, 06:21 PM	#7
SpeierRacing Junior Member Join Date: Oct 2011 Location: Hays, Kansas Posts: 77 Likes: 18 Liked 70 Times in 23 Posts	Re: Run out on valves I don't know anything I would run .003 guide clearance on! Most 11/32 intakes should be .0010-.0012 and exhaust .0013ish. 5/16 and under well under .0010.. People ask me all the time what is acceptable seat run out. Whatever your guide clearance is! .0000 is cool but doesn't matter in the grand scheme of things!