Tight valves and diagnosing "burned valves"

[Kevin Trent <trentkc@domain.elided>]

One opinion on the discussion of tight valve clearances claims that tight 
clearances will result in a burned valve.  My only experience with a burned 
valve was in a MGB where a bb-size hole formed on the edge of the valve, 
resulting in no seal.

Can anyone provide a more precise description of what "burned valves" 
really look like?  On the 1750 engine I'm building, the exhaust valves and 
seats were what I describe as being "pitted"- lots of very small pits that 
gave the valves and seats a speckled appearance.  The pitting could not be 
eliminated by lapping the valves to the seats so I had them cut.  The 
valves were new from a prior rebuild and had 80K miles on it; the exhaust 
lash was .020-.022.

//kct, Powell TN 
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