Location: Virginia Beach, Va & Port Charlotte, Fl.,
Posts: 2,294
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As far as the worn guides, do you think it was a geometry problem causing excessive side loading? I ask because replacing guides doesn't necessarily fix the problem, just bandaids the symptom. What are you doing to eliminate the possibility of future premature guide wear? Your thoughts??
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.
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
Posts: 4,533
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My guess is a a big, very-high lift cam. Detroit engineers probably didn't envision running much over .600 lift cams back in the 50s and 60s. Hard to avoid some side load even with all the latest roller rockers and everything. Running big performance stuff has got to increase wear and maintenance.
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