Valve Seal Wear Pattern Puzzle
10-13-2008, 07:42 PM
#1
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Valve Seal Wear Pattern Puzzle I am unable to explain the wear pattern on my valve seals and am looking for some better ideas. I have a small cam, Comp 918 springs, and stock LS6 lightweight valves. All of my exhaust seals (brown) have a wear pattern that shows clearly that the springs rotated. All of my intake seals (black) have a pattern that shows equally clearly that the springs did not rotate. My first guess was that rotation of the springs indicated at least some valve float - my engine routinely sees 6800 rpm and has seen 7000 rpm several times. That guess doesn't hold up because the exhaust valves, those that appear to have rotated, are lighter than the intake valves. A possibility is that all the springs rotated and for some reason the intake seals rotated with the springs. I don't think that happened because all the seals were snug on the guides when I removed them. Do these two patterns commonly appear? Does anyone here know the cause of the difference?
Last edited by Gary Z; 10-13-2008 at 07:57 PM.
10-13-2008, 10:48 PM
#2
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I used to have a link to a super slow-mo video made by pac racing. They cut away part of the head & valve cover on an engine and captured video of several spring types (including beehive) at high RPM. It turns our they all spin which isn't what I would have guessed.
I might have the link at work. If I can find it I'll attach it tomorrow.
edit: here it is
http://www.racingsprings.com/movies/PRI%20Web%204.wmv
I might have the link at work. If I can find it I'll attach it tomorrow.
edit: here it is
http://www.racingsprings.com/movies/PRI%20Web%204.wmv
Last edited by massls1guy; 10-13-2008 at 11:12 PM.
10-15-2008, 10:50 AM
#3
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The video is interesting but it only confirms what we know - valve springs can spin. I am still interested in understanding the difference between intake and exhaust shown by my seals. Has anyone here seen this difference on their seals?
10-15-2008, 11:32 AM
#4
I have not seen this, but perhaps it has something to do w/ the dimensional difference in valve movement between the intake & exhaust valve? Perhaps, the reduced lift on the exhaust valve also equals reduced spring clamp pressure that is allowing the spring to rotate. Maybe the spring manufacturer can explain or has specs that will confirm or dissmiss this thought.
