Posted by DDD [172.69.68.240] on Thursday, November 01, 2018 at 15:54:31 :
In Reply to: No. posted by Jim Lee [108.162.245.13] on Thursday, November 01, 2018 at 13:48:45 :
ORIGIANL POST I COPIED AND PASTED ABOVE:
"In a vacuum advanced distributor, the spark is advanced based on INCREASING
manifold vacuum"
OK I get it now.. so on pulling a hill, the vacuum goes to nearly ZERO..
so the next part. maybe this is where the Archived poster went wrong and is confusing me:
"In a centrifugal advance distributor it's strictly rpm.
As Henry mentioned, advance based on rpm is
blind to load: you're approaching a hill and
your timing is happily moderately advanced based
on your rpm, but as you begin to climb your
rpms don't go up, so you don't get any more
advance.
In a vacuum advanced distributor, the engine would
begin to work a little harder up hill, draw a
little more manifold vacuum and advance the spark some."
I think the last statemtn is the key, and what was confusing me...
Here it is again:
"In a vacuum advanced distributor, the engine would begin to work a little harder up hill, DRAW a little MORE manifold vacuum and advance the spark some"
ahaha! that's the key: the pulling of a hill will NOT draw more vacuum. there isn't any there in a hill climb... so that is NOT a correct statement.
in fact, then, the distro does NOT advance at all under a heavy load at all.
so, I guess I am looking in the wrong place (i.e. replace my MECHANICAL distro with a VACUMM distro to achieve better performance.
correct?