Hey guys, I have a bracket car with a Ford 460 / C8 heads. I found 3 rockers with bad fulcrum bearings(stiff, no side play) last time I checked lash. I also saw a strange wear pattern on the valve stem (see pic) that looks like the valve has been rotating back and forth. The rockers are Comp Pro Magnum. All other rockers are fine and show a nice contact line in the centre of the valve stem. Cam is a Lunati 30340506 with matching springs.
My question is whether the failed bearings are the cause of the problem or a symptom of something else. Any ideas?
BTW I shaded in the wear mark so it is easier to see.
Thanks!
Strange (to me) wear pattern on valve stem tip
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Strange (to me) wear pattern on valve stem tip
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Re: Strange (to me) wear pattern on valve stem tip
That is a multiple rocker tip pattern,The engine could have experienced valve float, you look to have 10°locks or Posi Locks so valve rotation should not occur unless you have rotators under the springs. There is a description and overview of the condition in the back of a Manley catalog.
The marking looks very defined,, and not random as if it had experienced float a number of times.
Do you check and replace springs as reqd in situ? this may explain the variance in marking.
Cheers.
The marking looks very defined,, and not random as if it had experienced float a number of times.
Do you check and replace springs as reqd in situ? this may explain the variance in marking.
Cheers.
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Re: Strange (to me) wear pattern on valve stem tip
That is the Bat signal.
Another way for that to happen is if you work on the heads, valves in and out.
Another way for that to happen is if you work on the heads, valves in and out.
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Re: Strange (to me) wear pattern on valve stem tip
I have seen that as well but not from head maintenance where valves were not installed in the original guides but from some weak springs not at the correct installed/open pressures.
I see that as valve float just starting or the valve seat may be in rough shape or not concentric to valve face. I had some Mopar heads a while back that had some weak springs and non concentric exhaust seat inserts that were installed..
I would check the open pressures of all the springs just to be safe. You will see wear marks on the stem if the retainer/s are moving a bunch.
I see that as valve float just starting or the valve seat may be in rough shape or not concentric to valve face. I had some Mopar heads a while back that had some weak springs and non concentric exhaust seat inserts that were installed..
I would check the open pressures of all the springs just to be safe. You will see wear marks on the stem if the retainer/s are moving a bunch.
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Re: Strange (to me) wear pattern on valve stem tip
Valve float yeah sort of but being BBF more a spring harmonic issue, where the spring seperates from the seat/retainer. Check rocker geo, make sure pushrods are up to task, of course valve seat/guide must be right and concentric.
Revise spring choice may be required.
Revise spring choice may be required.
Craig.
Re: Strange (to me) wear pattern on valve stem tip
Might be just the picture but are the guide plates correct for pushrod?
Looks like a fair amount of space on the side of the pushrod
Looks like a fair amount of space on the side of the pushrod
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Re: Strange (to me) wear pattern on valve stem tip
the pushrod looks hammered, maybe it's the angle but the oil hole looks off. Might be movement there