This weekend I was working on a '58 MGA that would start and run very
well, until it got hot. Hot is a kinda relative term, this mail group
being international and all, so let me say that the ambient
temperature was about 95 (35 C). The engine warmed up in about 4-5
minutes to 190 by the (recently rebuilt) temp gauge. It would then go
well for another 15-20 minutes, then would start missing, and over the
next 5-10 minutes would grow progressively worse until it would not
start at all. Not a pop, not a peep.
One thought was vapo(u)rlock, but the carbie bowls were full. Plugs
were more or less dry, matte black with a tinge of brown. I then
checked the spark when it was cranking, and it was this very puny
yellowy-white kind of thing. After letting it cool down (hood open)
for about ten minutes or so, it started right up.
My take is that it could be a spark problem. The coil is mounted
directly on the dynamo, and right behind the radiator. The coil is
original. The coil was extremely hot. I am given to understand that
on later models the coil placement was moved.
Any wisdom on this? I've ordered up a new coil, and am thinking about
mounting it on the fender well, if that is where it was moved to in
the later models. I'd appreciate confirmation of this notion.
A. B. Bonds
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