msecres@ibm.net wrote:
> a) Out of curiosity, how does one destroy a dizzy's vacuum advance by
> incorrectly setting up an ignitor? (Actually, mines a retard unit; nor
> did I set up the ignitor incorrectly ...)
You can't really, unless you tore the diaphragm during
handling of the unit. If you did, no big loss, it must
have been ready to go anyways.
> b) Is there any reason at all to revisit one's carburetor settings
> after installing an elec. ignition?
Yes. Carbs should be revisited after just about any changes, such
as valve adjustments and ignition work.
> c) How come all cars aren't set up at 0 degrees TDC, anyway?
The flame front takes time to propagate. This time is more
or less constant but the engine RPM is far from constant.
The effect is that the spark has to be started before it is
"needed", and the lead time changes with engine RPMs. This is
why the mechanical advance works with engine RPM.
The flame propagation is also effected by cylinder pressure,
which is why a "loaded" engine needs a different spark
timing, which is what the vacuum units do.
--
Trevor Boicey, Ottawa, Canada.
tboicey@brit.ca, http://www.brit.ca/~tboicey/
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