So I rebuilt my engine a few months ago, had a heck of a time
getting it running and after it was finally drivable it lost the
number 5 cylinder. Everything checked out good until I finally
bought a leakdown tester, which indicated that air was
escaping from the intake valves. So I tore it down, and found
that the valves were worn. What's odd about that is that I
had a valve job done and three valves had been replaced
because the old ones were extremely worn.Here's one of the valves that came out after 175000 miles:
 Now the only valves that are worn out are the three that were
replaced, and I've only put about 500 miles on it. Both the
valve and the valve seat are worn into a curve and the valve
needs to sink into the head to fit, but the lifter is holding it
open. It will hold 85 percent of the air in a leakdown test cold
with the cam out. Heres a couple pictures of the new valves:
 I'm really confused as to how this could happen, is it an issue
of the valves being too soft? Or the valve springs being worn
out? Any insight would be appreciated before I take it back
the machinist. I want to make sure when he fixes it it will
never happen again. Thanks in advance.
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Valve Issues (Soft Valves?) - 
