01-25-2016, 07:03 AM
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CC Member
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Join Date: Dec 2001
Location: Louisville,
KY
Cobra Make, Engine: I'm Cobra-less!
Posts: 9,417
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Not Ranked
1. Bad surface finish on valves.
2. Guide material was junk.
3. Possibility of an over-efficient valve seal in an oil restricted environment.
Pick one or two. Haven't finished up the analysis. Leaning towards valves stem surface finish on some custom hollow-stem Ferrea valves. Talking with other builders, at least one had seen this before and labeled it a valve stem problem.
However, it wasn't a geometry issue. Guides were worn concentrically on all valves instead of in one axis and with a T&D race roller rocker arm leaving a .050-.055" pattern on a valve stem, there is little possibility of a side load.
My reluctance to give a clear answer was because I can rule out geometry but I don't have a 100% target to point my finger at right now. |
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