From: Alex Baroiant <abaroian@polymail.cpunix.calpoly.edu>
>
> If I change my coil to a higher power 40,000 volt unit, do I need to make
> any other modifications to the electrical system, like the battery, wires,
> or the alternator?
Alex:
If you are using the Lucas Sport Coil, or any other coil that does NOT
require a ballast resistor, AND your MG came from the factory with a ballast
resistor, you need to bypass the resistor. You can very easily do this by
connecting the plus terminal of the coil to ANY convenient white wire. There
is no need to remove any wire already on the plus terminal, nor do any other
changes need to be made.
Later model MGs came with the ballast resistor, from about '75 on, I believe.
There are two ways to determine if your car has a ballast resistor:
1) If the coil has only white wires on the plus terminal, it does not have a
ballast resistor. If it has two white/light green wires, it has a resistor.
This will work if your car's wiring has not been modified.
2) With the key on, measure the voltage at the plus terminal of the coil. If
it is equal to the battery voltage (12.6 volts, depending on battery
condition), there is no resistor. If there is a resistor, the voltage will be
significantly less - 6 to 9 volts. This will work even if the wiring has been
modified.
For further discussion on this subject, see:
http://www.vtr.org/maintain/ballast.html
Although this article was written for Triumphs, it applies equally to MGs.
There is another article that may be of interest on the VTR maintainance
pages - a brief description of how an alternator works, written in
non-technical terms for non-electricals. It can be found at:
http://www.vtr.org/maintain/alternator-overview.html
Hope all this is of benefit!
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition
'68 MGBGT---organ donor for the '74
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