Ah, I see it is a dual point.
My guess Marty is that you are looking at the shorting points not the
control points. The way a Dual point distributor works is that the dwell
(the time the points are closed and the coil is being saturated) is
increased by a set of shorting points. The shorting points open before the
control points, but nothing happens because electricity is still flowing
through the control points to the coil. When the control points open, both
pairs of points are now open, so the electricity is cut off, the magnetic
field in the coil collapses, and the spark fires. Shortly after the control
points open the shorting points close and start charging the coil again.
With only one set of points you'd need a heavy points spring and a radical
points cam to get the points closed fast enough at high RPM. That would wear
the rubbing block like crazy. But with dual points the shorting points are
starting to close as the control points open, so the dwell can be much more
precisely adjusted.
It's the second set of points opening that triggers the spark.
-----Original Message-----
From: owner-fot@autox.team.net [mailto:owner-fot@autox.team.net] On Behalf
Of Bill Babcock
Sent: Thursday, May 26, 2005 9:55 PM
To: 'Martin Sukey'; 6 pack digest; FOT; Triumph List
Subject: RE: Non VTR help needed (distributor)
Doesn't really matter where the distributor points, that's just a handy
thing to have a standard approach. Usually you install the disty with the #1
cylinder on it's firing stroke (both valves closed) and the rotor pointing
at the #1 spark plug. All that's happened is someone pinned the drive on
backwards. It only goes in the engine one way (the drive tongue is offset),
but you can drill the hole and pin the drive anywhere. Mallory distributors
are usually supplied with no drive. You drill and pin on your own. Someone
did you a "favor".
All you need to do is slip in the distributor, turn the engine to just
before TDC with both valves closed on #1, and rotate the distributor housing
until the points are just starting to open. That should be close enough to
start the engine. Wherever the rotor is pointing is where your #1 plug wire
is going to be. The rest of the wires go in order, counterclockwise #2,4,3.
(I'm assuming TR3/4). Now start it up and set your timing.
-----Original Message-----
From: owner-fot@autox.team.net [mailto:owner-fot@autox.team.net] On Behalf
Of Martin Sukey
Sent: Thursday, May 26, 2005 6:05 PM
To: 6 pack digest; FOT; Triumph List
Subject: Non VTR help needed (distributor)
Well my Mallory dual point distributor finally arrived today after being
back ordered since February from more than one source. So I go to put that
sucker in tonight and it has me totally confused. If I look at my stock
distributor when the rotor is pointing directly at the number one cap
terminal the points are closed and are in the center of the flat dwell area
of the distributor cam. When I take my new distributor and place the rotor
pointing directly at the number one cap terminal the points are fully open
and on the lobe of the distributor cam. TOTALLY OPOSITE. I have looked at
this for the last hour thinking that I am missing something and looking at
it backwards but NO THATS REALY THE WAY IT IS. There is no adjustment. So,
can somebody that knows more about this sort of thing than me explain what
the heck is going on here?
Help me, I want to go autoxing Monday:-)
Marty Sukey
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