> I still wrestle with the pain in the a$$ idle, I believe it was
> Randall that
> mentioned checking for the a worn dizzy shaft etc. What does this entail
> really? Is it the top part of the dizzy that gets worn or is it the lower
> drive part?
What usually wears is the rather large brass bushing in the bottom of the
distributor housing. It's possible for the upper piece (that carries the
rotor) to wear against the shaft, but it's not usual. Since the bushing is
much softer than the shaft, it usually gets the majority of the wear.
> Can I test in car or components coming out and bench
> tested.
In-car, turn the engine until the points are open. Grab the end of the
shaft and try to move it towards the points, then away, while watching the
point gap. The movement should be very small, ideally too small to see
(although almost certainly you will feel a little bit).
The timing light is another way of checking ... under the light, the hole in
the pulley should appear to be stationary. If it dances around at any rpm,
a worn dizzy is the most likely culprit.
Did you ever check the advance operation ? This is a good time to check it
too ... with the light connected and shining on the pulley, slowly rev the
engine up & back down. The hole should smoothly move towards the RH side as
you rev the engine up, and then smoothly move back to it's original position
as you let it back down. If it doesn't move, jumps, jerks, or doesn't
return to the same place, then your centrifugal advance is suspect.
Have you checked for intake air leaks ? Spraying WD-40 or carb cleaner on
suspected leak sites with the engine idling is a good way to check, if
you've found a leak then the engine note will change. But be warned these
are both flammable. If it does catch fire (very unlikely), just be cool, it
will go out almost instantly and not harm anything.
Think I mentioned before, a leaking float valve can also cause erratic idle.
Usual symptom is that it idles OK at first, but "loads up" and starts
running poorly, maybe even dies.
Randall
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