> wrong one. The
> number on the advance is 2-6-3. He told me that it means that
> the advnce moves
> the timing 2 degrees when the vacuum is 6 millimeters of water and it
> progresses to a maximum of 3 degrees advance. Pretty neat. I
> always wondered
> just what the hell those numbers meant.
I have been pondering this for the last couple of days, and, at the risk of
being castigated for writing about something of which I have no real
knowledge, I have to say that this particular explanation of these numbers
sounds a little fishy to me, for a couple of reasons. First, a vacuum of
6mm of water is around 1/4" wg, which isn't very much at all. When you
consider that 1 atmosphere is about 33 feet of water, then a 1/4" represents
6/100% of one atmosphere - the kind of pressure variation you could
experience just by driving up a small hill! Maybe the units are wrong. I
could see the 6 representing the number of inches of mercury - a full vacuum
is about 30 inches of mercury, so I would think 6 inches of mercury is the
more likely unit, and vacuum is generally measured in inches of mercury,
anyway.
Secondly, I always thought the distributor maximum advance was much more
than 3 degrees. Isn't it more in the order of 10 or 20? Or am I
misunderstanding something here?
I will now sit back and wait to be enlightened...
Merry Christmas, one and all!
Michael J. Marr, P.E.
Naperville, IL
1960TR3A
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