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General Minitrail Talk
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71K0 just brought out of a LOOONNGG storage.
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<blockquote data-quote="69ST" data-source="post: 175090" data-attributes="member: 5"><p>I can empathize, as in "<em>been there...done that</em>...". That said, think about this from a coldly rational perspective. What, exactly, would a low-quality valve really mean? Metallurgically, it'd essentially mean an alloy that's either too hard or too soft. In real-world terms, that'd be stainless, stellite, or titanium...expensive, <em>expensiver</em> and <em>expensivest. </em>Aside from the fact that these materials are way too costly to be used for cheap valves, non-magnetic stainless is the material used for good quality exhaust valves, in these engines...always has been. If a hardness "mismatch" between valve & seat were an issue, these things would be notorious for wear problems this <ostensibly> would cause. But, it's the intake side that has some issues, the exhaust side has proved virtually indestructible. Those (in)famous "tuliped" intake valves exemplify what can happen when the valve is softer than its seat...the valve wears-out, not the seat. Any seat erosion is the result of high-pressure/high-temp combustion gases leaking past the valve (that manifests as the ever-popular blackened intake port)...and minimal. The most "out there" scenarios I can imagine would be a mismatch with the valve guide. Too tight, or too loose, the engine would run like crap, at best. No engine is going to run with a stuck valve. IOW, this is a non-issue.</p><p></p><p>Unless the engine swallows a valve, i.e. the head breaks off, or the valve seizes and gets overly-familiar with the piston, there's virtually no chance of any serious damage. Worst case, in real-world terms, the guide is worn...necessitating a new guide, valve, seat cutting & lapping. Then it's cake & ice cream for everyone...<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink ;)" loading="lazy" data-shortname=";)" /></p></blockquote><p></p>
[QUOTE="69ST, post: 175090, member: 5"] I can empathize, as in "[I]been there...done that[/I]...". That said, think about this from a coldly rational perspective. What, exactly, would a low-quality valve really mean? Metallurgically, it'd essentially mean an alloy that's either too hard or too soft. In real-world terms, that'd be stainless, stellite, or titanium...expensive, [I]expensiver[/I] and [I]expensivest. [/I]Aside from the fact that these materials are way too costly to be used for cheap valves, non-magnetic stainless is the material used for good quality exhaust valves, in these engines...always has been. If a hardness "mismatch" between valve & seat were an issue, these things would be notorious for wear problems this <ostensibly> would cause. But, it's the intake side that has some issues, the exhaust side has proved virtually indestructible. Those (in)famous "tuliped" intake valves exemplify what can happen when the valve is softer than its seat...the valve wears-out, not the seat. Any seat erosion is the result of high-pressure/high-temp combustion gases leaking past the valve (that manifests as the ever-popular blackened intake port)...and minimal. The most "out there" scenarios I can imagine would be a mismatch with the valve guide. Too tight, or too loose, the engine would run like crap, at best. No engine is going to run with a stuck valve. IOW, this is a non-issue. Unless the engine swallows a valve, i.e. the head breaks off, or the valve seizes and gets overly-familiar with the piston, there's virtually no chance of any serious damage. Worst case, in real-world terms, the guide is worn...necessitating a new guide, valve, seat cutting & lapping. Then it's cake & ice cream for everyone...;) [/QUOTE]
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General Minitrail Talk
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71K0 just brought out of a LOOONNGG storage.
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