Eric,
After a few annoying posts to this list (by me), I was sent a note to contact
Jeff at Advanced Distributor. I have a late 1275 with SU's that don't have
the vacuum ports on the carbs and the car had a late 60's distributor that was
expecting ported vacuum. It just plain wouldn't work, the high vacuum at idle
caused the distributor to advance to it's full extent, about 25 degrees. If I
adjusted the timing at idle without the vac advance and then connected it back
I was way too far advanced. If I adjusted the timing with the vacuum advance
connected to the distributor, there wasn't enough advance under higher RPM's.
My temporary solution was to just cap the manifold port and use to centrifugal
advance built into the distributor, 28 degrees in my case. The car ran better
but still not right, it had a nasty stumble under WOT because it took a while
for the mechanical advance to catch up. I contacted Jeff at Advance
distributor and he had a Cooper S specification, no vacuum advance, core that
he re-curved for my application and sent it to me. I installed it a couple of
days ago and it appears the it is going to solve the problem I have been
having with the stumble. I would strongly suggest that you contact Jeff and
see if he can help you. jeff@advanceddistributors.com
----- Original Message -----
From: David Lieb
To: Spridget List
Sent: Thursday, September 14, 2006 9:36 AM
Subject: Re: Pertronix Distributor
>>> could you please explain why the 123Mini line dizzys (I guess you mean
>>> 123ignition) doesn't work with manifold vacuum? I see no reason why it
>>> wouldn't.
If you were to connect a vacuum gauge to a tap on the manifold and another
one to a ported vacuum tap and run the engine, you will see that the signals
are very different and that, if the distributor thinks it is reading one and
is actually receiving the other, it will not be a good thing at all. You
would get the wrong advance almost everywhere.
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