I went full circle with the ignition in my TR4 racer, the car came with a
Mallory dual point. Thinking I would be better off with an electronic
ignition, I went through a pile of Lucas dizzies on my shelf and found my
best one, got a Crane XR700 and thought I would be jake. In a word, no.
High speed missing. The shaft was tight, the mechanical advance looked
great but spark scatter was awful.
The XR700 came with a shutter plate that fit the Mallory, so I pulled the
guts out of the Mallory and used the it to fire the XR700. Again, didn't
work well. It worked way better than the Lucas did, but still had that high
speed miss. I tried a couple of different coils, with and without a ballast
resistor, no joy.
So I reverted back to the dual point setup in the Mallory, and life is good
again.
The thing about MSD boxes seems to be not IF they will cause a DNF, but
WHEN will they cause the DNF. I never ran an MSD box, but just about
everyone I know that has run them has had trouble with them. At Grattan the
Snook's Dream Team Alfa cooked another one. Also, I have seen dyno proof
that they do not add anything to the TRactor motor power.
I understand why autocrossers need a rev limiter. In the 30 to 90 seconds
of bliss a typical autocross run lasts I never even think of looking at my
gauges. Maybe autocrossing will not heat an MSD up enough to be a problem,
but if I were building an autocrosser, I would look at other rev limiter
options.
Off to get wet at the Glen today.
Cheers
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