Re: How Important is OMC Ignition Timing?

[legendre]

quote Richard A. White:

So, if points are set to open exactly 180 apart, I understand how that helps. does the points cam and or cam lobe automatically set the opening to .02?

Here is why I ask, If I set the points to open 180 apart, then rotate just past that point and then set them to .02, I will in effect, possibly change the location of them opening.
I am thinking the lift of the cam will get the .02 needed….correct?

If the points are just beginning to break open at the position indicated by the timing tool / mag plate relationship, they will measure 0.020" – within reasonable tolerance – when fully open. The idea being, that by design (and careful manufacturing) the crest of the points cam is approximately 0.020" higher than the correct "fire" point at the base of the rising slope. It may in fact be that the crest of the cam is (almost) exactly 0.020" taller than the base circle (aka 0.020" total lift) but I can’t say that’s the case – easy enough to measure, though.

While the actual points gap is reasonably important, as it effects the dwell time and hence ignition efficiency, having the two cylinders firing exactly 180′ off and at the correct time is ultimately more important to running quality.

Or that’s as I understand it.