ron i cant remember if you said that you had used some nice used valves?
if so i think you might encounter a problem there. reguardless of what they
might look like they have an established wear pattern from old guides with a
standard lift cam. with a difrent lift cam this puts the valve traveling
further into the guide than it was previously. so at 1 piont you have the
valve stem going down into the guide for it's first time at the top of each
lobe. the rest of the travel is already the same as it would be on a stock
cam with little exception.
combining exhaust heat(expansion) with the posibility of close tolerances at
guides ,exhaust valves live in a pretty severe climate. this could cause
sticking and binding after it is warmed up. we often made exhaust guides a
little looser than spec. called for. also took a die grinder and sheared
off the protruding end of guide in the exhaust ports only! better flow,
and less guide to worry about siezing on the valve stem.
now stiffer valve springs relates to more pressure on the rocker shaft on
the bottom side of shaft. excessive tolerance between shaft and rockers
results in poor top end oiling. stock rockers are ok with a mild engine as
long as they were ok to start with. care must be exercised when doing
modification due to a trickle down effect. 1 thing was changed and 3
things were changed from an established prior wear pattern to something
diffrent. i hope that this might be of assistance with reguards to your
problem.
chuck
still hunting for clue musk(he-he)
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