> It seems as if the method Randall describes is most accurate
> cause 180 degrees
> opposite the TDC can be measured exactly. Whereas, "the nine
> rule" isin't as
> accurate because one has to make a judgement call as to when each valve is
> fully open by oberving ether the valve stems or through the spark
> plug hole.
It actually doesn't matter (or at least shouldn't). The cam's base circle
should be perfectly centered on the cam, so the valve lash remains the same
for at least a full crank revolution. So, it shouldn't matter where you are
in that revolution, as long as you're somewhere in it.
Which is why both methods work, even though they have the crank/cam in a
different position while the valve is being adjusted.
Randall
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