John---If you used a dial indicator to pick up this .0025 off the points
opening cam that would be quite a bit. Especially if you did not
influence the shaft with side force during the reading.
What you read could be either play between the shaft and bushings, OR a
bent shaft just below the cam. If it's the shaft, then replacing the
bushings won't cure the runout. The runout from a bent shaft will have
the largest differences 180 deg. apart.
Probably more important is how much all of this affects the ign. timing.
An engine should run well if the idle timing is set at 10 degrees BTDC.
(No vacuum influence) If the engine happens to see 12 or 8 degrees
BTDC, it will still run decently, even with a variation. This carries on
up to maaximum ignition advance. So, If you were picking up a
difference of a few degrees in timing at the front pulley from whatever
is causing the runout, this would not be critical to anything but a high
performance engine, looking for maximum power and timed to run at the
edge of detonation.
Do not take this as a reason to not try correcting what you are finding.
It's just that a lot of these engines have some variation in timing and
run well.
My Craftsman dwell meter did not pick up the variation in angle. There's
two degrees difference between my #1 & #6.
Dick
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