I was intrigued by the latest posts form RJ regarding valve adjustment because I have been experiencing a miss at idle. So I decided to adjust the valves according to the "nines" method. All the posts made sense to me.

So I tried it this afternoon.
'72 B20, 0.030" over, IPD Street Torque cam w/ probably around 170K on it, compression 120+/- across all four cylinders, valve job around 35K ago.
I adjusted the valves 0.016" - 0.018" (warm, go / no-go) by the "nines".
After the engine cooled, there was no appreciable difference.

After I was done, I continued to check the clearance throughout the rotation of the cam. What I found was that when one valve was completely open the opposite valve on that same cylinder was now in excess of 0.020". This was the case for all four cylinders.

That doesn't seem right to me. If by the "nines" is at the lowest part of the lobe, why am I getting more clearance somewhere else on the lobe?

Ultimately, I adjusted the valves 0.016" - 0.018" at the spot of minimum clearance. I'm now thinking that that may not have been a good idea in that I may burn a valve.

Any thoughts anyone?
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Tom - '60 544, '68 220S, '70 145S, '86 745T, '06 Mazda MPV