[DeTomaso] Ignition Coil Failures

[Asa Jay Laughton]

I don't have coil issues, that I'm aware of.  Just my two cents here.  
On my 1971 Mach I, there is a cable that goes from the negative of the 
battery, directly to the engine block.  There is also a secondary cable 
that attaches to the bodywork.  It makes good sense to me.

To run a larger cable from the battery all the way back to the engine in 
a Pantera seems a bit of overkill, but maybe that's what you need.  
Check the ground at the battery.  Get some long leads for your 
multimeter and measure the resistance from the negative post of the 
battery, to the engine block.  Don't forget to subtract the resistance 
in the leads.  If the resistance is high, you need a better ground to 
the engine block.

Asa Jay

Asa Jay Laughton, MSgt, USAFR, Retired

& Shelley Marie
Spokane, WA

1973 Pantera L 5533
[ASASCAT]
    
******************************     
http://www.asajay.com
http://www.351c.info
  



John Taphorn wrote:
> 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
> _______________________________________________
>
> Detomaso Forum Managed by POCA
>
> Archive Search Engine Now Available at http://www.realbig.com/detomaso/
>
> DeTomaso mailing list
> DeTomaso at list.realbig.com
> http://list.realbig.com/mailman/listinfo/detomaso
>
>
>