Bob,
Best to re-read my instructions...
In a nutshell, it says that the phasing of the ignition
event with respect to the phasing of the rotor is important.
I dissagree that arbitrarily rotating the distributor to make
the ignition fire at the correct angle is the right way to adjust
the timing.
You just cant assume that rotating the distrubtor to get the right
ignition timing will truly fix all the evils.
As I said before, and many times before that, getting the ignition
timing right is not enough, the timing must be right AND it must
occur when the rotor is pointing at the correct cap terminal.
In addition to that, it must be phased across the entire advance
range for the mechanical and vacuum advance.
The advance hook on the 25D lucas rotor only provides for around 20 degrees
of mechanical advance, so if you rotate the distributor 22.5 degrees
to compensate for the sensor not being mounted in phase with the
rotor, then the spark will occur when the rotor is NOT pointing
at the proper plug wire.
This results in weak spark at that plug, or misfire to the closest
cap terminal.
I have seen a great many aftermarket ignitions that suffer from
this problem pertronics is just one of them.
Jarrid Gross
-----Original Message-----
From: Bob Hamilton [mailto:hamilton@accesswave.ca]
Sent: Wednesday, November 29, 2000 11:18 AM
To: Jarrid Gross; CANISDOG@aol.com; alpines@autox.team.net
Subject: RE: Pertronics Problems
Jarrid,
Jarrid and others,
I have installed Pertronix on over a half dozen cars of various
makes (Sunbeams, Midgets, MGA's) and have to disagree with Jarrid on the
position of the sensor in relationship where the original points were
installed.
There are four magnetic poles on the magnetic sleeve that fits
over the dist. cam. Any one of these magnets can trigger the ignition coil
so the sensor can be placed anywhere on the mounting plate. Pertronics
design usually same mounting points (threaded holes) as the original points
which does not necessarily coincide with the exact trigger position for the
original points. The distributor may (read usually) has to be rotated in
the clamp in order to re-establish the trigger point. On a 4 cylinder
engine, this can be as much as +/- 22.5: (i.e. total of 45:) either way of
the original setting in order to pick up the field from one of the magnets.
You should not have to rotate your distributor any more that this in order
to have the sensor pick up a field from *a* magnet, doesn't matter which
one.
On my Sunbeam Talbots the sensor is mounted where the capacitor
was which is on the opposite side of the mounting plate from where the
points were mounted and when I first tried to start it for the first time
without adjusting the distributor, it was firing on the compression stroke
ant stopped the engine instantly, i.e. the timing was far too advanced. I
rotated the distributor in the clamp to retard it by roughly 20: in order
to get it running and then set it as usual using the timing light.
Let me know if I can clarify anything I have written here.
Regards,
Bob
At 09:53 AM 11/29/2000 -0800, Jarrid Gross wrote:
>Paul,
>
>If the ignitor were installed in the same position as the points,
>and the rotor magnets cross the ignitor in more or less the same
>position. then this shouldnt have been a problem.
>
>Are you talking 180 crank degrees here, or cam/distributor degrees?
>
>Sounds like the pertronics didnt mount exactly like the points did,
>and the side cover plate wouldnt let you change the timing to what
>you needed, so you had to use the other side of the cap to make it
>work.
>
>When you mout ANY aftermarket ignition, you want to mount it so that
>with the engine at #1 TDC(#1 valves closed), the dist in its nominal
>position, the rotor pointing straight at the #1 cap terminal, when the
>points just begin to open or the sensor is triggered, and the spark occurs.
>You want to test for this with the cap off, so you can see exactly
>what happens.
>
>If the above circumstances doesn NOT occur, you must mount the sensor
>points so that it does, OR ELSE THE MECHANICAL ADVANCE WONT WORK,
>and you will have a weak or non-existant spark.
>
>
>
>Jarrid Gross
>
>-----Original Message-----
>From: owner-alpines@autox.team.net
>[mailto:owner-alpines@autox.team.net]On Behalf Of CANISDOG@aol.com
>Sent: Wednesday, November 29, 2000 8:44 AM
>To: alpines@autox.team.net
>Subject: Pertronics Problems
>
>
>Has anyone had problems get the timing right with the Pertronics ingnition
>system. I have had to "flip" my distributor 180 degrees to get the timing
>right.
>With the distributor in the standard position (vacume advance on block
side)
>the vacume advance hits the block before correct timing can be made. If I
>move the wires one position...then I have my vacume advance all up in my
dip
>stick!
>I called Pertronics and they said this should be a "drop in application"
and
>I should not have to move my distributor. They had me check the voltage
and
>everything checks out. (not using the ceramic resistor)
>Any input would be nice. Bought it from SS and had Pertronics check out
the
>number on it, they said it is the right one for the application.
>
>Paul
>Colorado
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Robert (Bob) A.C. Hamilton, Waverley, Nova Scotia, Canada
The Man of Many Sunbeams - Alpine, Drophead and Saloon 1953-1954
[Stable mates - 1973 Midget and 1968 M-B 280SE]
Home Page: www.navnet.net/~hamilton
BATANS Home Page: www.batans.ca
E-Mail: hamilton@accesswave.ca
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