Has anyone had experience with the Intermotor coil (believe the model No. is
11000)? It is promoted as having a reasonable resemblance to the original
Lucas unit with a threaded hi-voltage connector.
My '63 B had an infrequent tendancy to misfire under load when thoroughly
warmed up. Everything else in the ignition had been replaced 6 years ago in
a major restoration, with few miles since then, so I suspected the (original)
coil to be the culprit and purchased an Intermotor from Moss.
I had driven with the new coil for about 30 minutes when the engine died.
Found the coil to be too hot to touch and the spark alternating between
healthy (jumped ~1cm gap) and essentially nonexistant. The engine would not,
however, fire at all when cranked. After it had sat about 20 minutes, it
started but ran roughly for the 2 miles home. I measured identical resistances
in the windings of the new and original coils, but was surprised to notice the
new one, when shook, sounded like it was only half full of oil, while the old
one was silent (presumably full). When I re-installed the original coil, the
engine just purred, relatively speaking, and the coil got only pleasantly warm.
Moss, to their credit, agreed to just send me another coil - didn't even ask
for a return (as electrical items are not returnable). In the meantime, I had
replaced the capacitor, just because it's cheap and hard to test, and
re-cleaned all the HV wires. The misfiring *seems* to be gone so I haven't
installed the replacement coil (which also makes a half-full sloshing sound).
The primary terminals on the new coils are simply marked + and -. I connected
+ to ground to conform to the car, but as the coil is a generic part, it was
undoubtedly designed for a negative ground system. The Moss rep thought I had
wired it correctly, but I believe he was no more certain than I was. My guess
was that it could be wired either way since only the polarity of the spark
would be changed if the polarity of the primary was reversed. This may have a
subtle effect on plug performance/life-time, but not cause a serious short-term
problem.
Does anyone know if grounding the coil opposite to the intended configuration,
regardless of polarity considerations, could have produced all the heat? Has
anyone used one of these new things successfully in either a positive or
negative ground car??
RsW
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