Re: Ignition Question - Part II

[Angus Holliday <trstag@domain.elided>]

At 05:21 PM 3/10/99 +0000, you wrote:
>

>I now have another related problem.
>Can anyone explain why Leyland switched from a single point distributor to a
>dual point distributor? Its my guess that it was to reduce the rate at which
>the points burn out - is this correct? Also, am I right in assuming that
>each set of points only deal with 4 cylinders each? I can't find any info to
>corroborate this.
>
No on all counts ..the idea behind double points as they are used in the
Stag is to increase the saturation time for the coil.
(the amount of time it has to charge between firings)   The points, being a
mechanical device, can only open and close so fast
without bouncing.  This is the same concept as ramp speed in camshaft
profile design.  The coil fires only when both sets of points
are open.  In practice this works as follows: one set of points opens and is
on the way to closing when the other set is just opening,
at that point the coil fires and the first set immediately closes  With the
first set closed the coil is then again charging.  This allows a hotter
spark and higher RPM in theory.  Some Americn hot-rod distributors do indeed
have 1 set of points for each 4 cylinders.  All in all the Stag works much
better with an Illuminition Electronic.  Those solid state devices are even
quicker and you don't get the erratic
dwell that comes with shaft wear.  Also the plates don't suffer from the
mechanical side loading. And of course without points
the dist tuning stays where you put it...no point rubbing block wear or
surface pitting. In practice faster starting, better performance 
and mileage and as an added bonus....if its out of tune you can blame the
Strombergs!  (usually)

Walter Holliday
Stag Specialists