John,
I've been running a Pertronix unit on my '76 TR6 for about 8 years now. You
are correct that the later models have a ballast resistor built into the
wire connected to the coil instead of a separate ballast resistor. Dan
Masters gives a thorough explanation of the function of the ballast resistor
on page 85 of his Electrical Maintenance Handbook. Essentially on the later
cars the ballast resistor allows for 12v to the coil when starting the car
and cuts it to 6v once the car is running and the key is in the 'on'
position. The later cars also run an ignition coil designed to work in
conjunction with the ballast resistor and the 6v feed.
>From what I read though the Pertronix unit works best with 12v all the time.
I ended up switching to a Lucas 12v (non-ballasted) sport coil when I
installed the Pertronix. I then just eliminated the ballast resistor wire
and replaced it with a regular wire from the fuse box to the coil to provide
the constant 12v feed. This set up has worked out great and provided
thousands of miles of trouble-free driving.
Andrew Mumford
'76 TR6
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Date: Fri, 28 Sep 2007 20:34:05 -0400
From: John Mitchell <jmitch@snet.net>
Subject: [6pack] Pertronix installation
In the directions for the pertronix unit, it says that for cars with
a ballast resistor, the red wire should be connected between the ballast
resistor and the ignition switch. On a late model TR6 it's buried in
the wiring harness. Has anyone done this, or should I just connect it
to the coil? Thanks John Mitchell 76 TR6
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