In a message dated 97-12-17 14:48:33 EST, CREICHLE@nsc.msmail.miami.edu
writes:
> Where did you get the idea that you need two coils to take advantage of a
> mallory dual point distributor or that you could even hook this up if you
so
>
> desired? The purpose of the dual points it to increase reliability and
> accuracy of spark timing not to use two coils.
Chris:
I got the idea from the hundreds of dual point/dual coil installations I've
seen in the last fourty years or so (mostly in the first half of those fourty
years - advances in ignition technology have just about rendered them
obsolete). Admittedly, never on an MG. As a matter of fact, I don't know how
you would hook up a dual point system to use only one coil, or why. The
statement I was responding to was "you get a hotter spark." From my knowledge,
limited though it may be, I can tell you that you won't get a hotter spark
from a single coil, no matter how many points you use. Reliability and
accuracy are another story, and if you can hook up a single coil to use dual
points, reliabilty and accuracy might well be improved.
Always willing to learn, I would be interested in the connection scheme for
dual points with one coil. Are they wired in parallel? In series? Is the
purpose to share the switching load? I'm curious. Keeping in mind that the
points open to fire the coil, both sets would have to be open at the same time
if they were in parallel, so I can't think of any advantage to that, either
from a reliability or accuracy standpoint. If it's just to share switching
loads, a simple set of larger contact points would do that. If they were wired
in series, then each one would operate exactly half the time as compared to a
single point set. Is that the purpose? How would that improve reliabiliy and
accuracy? It would, of course, double the life of the points, but you have to
buy two of them, so what is the gain? Educate me!
The last dual point/dual coil installation I've seen was on a Ford 302 powered
TVR that a fellow brought to the local Townsend car show about five years ago.
He had found an old dual point distributor at a flea market, and had installed
it with dual coils. He didn't use it for performance gains, but, like me, he
is an OF, and used it just for nostalgia sake. I was so impressed with the
Ford engine in his car, that I decided then and there to put one in my TR6,
but without dual coils.
> With electronic ign. you
> don't have to worry about burning the points so you can go for the higher
> output coil and larger spark gap to produce a fatter spark which will ignite
> the fuel more reliably providing easier starts, better fuel economy and
> possibly a bit more power depending on how you set it up.
I won't argue with that, but I still say a well set up stock system is
adequate for normal street driving. Having said that, I must confess - I have
a Crane/Allison electronic ignition, with a Lucas sport coil, in my TR6.
Primarily for the "hey, look at that!" factor, and for the reduced tune-up
schedule.
> I am the master of
> the runon sentence...
My favorite kind of sentence!
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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