[DeTomaso] Ignition Coil Failures

[Larry - Ohio Time Corp]

Hi John,

You are correct in saying that the coil will not be damaged when the key is
on and the motor is not running with your electronic ignition. Even with a
points setup, leaving it on for only 30 seconds per start up would not cause
a coil problem.

We spent over $800 on a company truck repair that could not be fixed till I
replaced the coil. The shop would not believe that fixed it, but they did
refund $500 dollars.

Yes, grounding is important, but no more then what is normal. Heat and
vibration always need to be minimized.

Bottom line is most things being made in the world today are just crap. I am
still shocked at the number of products that are bad right out of the box.

Larry - Cleveland



-----Original Message-----
From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
Behalf Of John Taphorn
Sent: Wednesday, September 03, 2008 10:01 PM
To: detomaso at realbig.com
Subject: [DeTomaso] Ignition Coil Failures

The Space City Chapter recently helped me diagnose an RPM related vibration
in my engine.  I noticed the vibration after installing the new roller cam
in my engine.  It started around 2400RPM and grew worse until about 3000RPM
and seemed to trail off after that.  Fortunately, It sounded like a misfire
to Dan Mixon and this helped us diagnose it; although others, including me,
at first thought it mechanical related.

My initial thought was that it was an unbalance caused by the double disc
clutch pack. It is a big unit that I always thought would be difficult to
fully balance and could only assume the shop had done it correctly.
Accelerating a longer story, it ended up that it was the MSD Blaster 2
ignition coil.  This is the second MSD coil I have had fail.  Admittedly, it
may be my fault.  On more than one occasion I have inadvertently left the
ignition switch on without the engine running.  Also, my start routine
includes turning the ignition switch to "on" and allowing about 30 seconds
for the Accusump to prelube the engine before starting the motor.  I may be
frying the coil with these actions.

I understand that on a conventional point ignition, if the points happened
to be closed, turning the ignition "on" without starting the car could burn
the points and overheat the coil.  However, I didn't think that to be the
case with the MSD mag distributor and 6AL.  Perhaps I am wrong, and I have
been cooking the coils.

MSD has a Forum at the website that has a troubleshooting section.  Not
surprisingly, they describe their coils as sturdier built and more reliable
than competitor's coils.  The technician says that the reason coils fail are
generally because of too much resistance in the secondary circuit.  This
includes bad sparkplug wires with too much resistance, plugs and
inadequately grounded heads. They elaborate on the importance of grounding
the heads to each other and the block and then directly to the battery, not
the chassis.  This theme seems to surface often when they review failure
causes of other ignition components as well. I would think the head bolts
would adequately ground the heads to the block.  However, I doubt many
Panteras ground the heads or block directly to the battery due to their
distant proximity.  

I am already employing an additional ground strap from the starter bolt to
another chassis stud.  Yet, now I am considering running an ~ 6 gauge cable
from the heads to the stud in the front trunk where the battery grounds.  It
would be relatively easy to do.  

I am curious of other's thoughts on the importance of grounding the engine
to the battery and whether they have addressed it?  Anyone else with coil
issues?

JT
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