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#1 |
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What is the acceptable run out on new valves?
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#2 |
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You would prefer the needle on the indicator not move. Less than .0005”
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#3 |
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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.
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Alan Roehrich 212A G/S |
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#4 |
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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.
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#5 |
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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?
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Dave Noll, E/FS ,?/SA 6526 |
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#6 |
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Go ahead and split hairs.
Then TQ the head down and distort everything. I bet very few use a TQ plate doing the seats.
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Adger Smith (Former SS) |
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#7 |
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And how much clearance should be run guide to stem??
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#8 |
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You have used up all of the tolerance. If the valve is out of concentricity the valve will hit the high side of the seat on the side with the greater run out. The spring will cause the valve to conform, bend, to the seat. How many cycles will it take for metal fatigue to appear?
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#9 | |
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That's not to say that if the valve pounds into the seat you won't have the same issue. For me, it's a simple question: Why start with poor run-out when you don't have to? Is it the valve or the valve-grinder? Quality valves with good margins tend to eliminate a lot of guesswork. Same goes for quality grinders that are well maintained and have the right stone and good, clean oil.
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#10 | |
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