[Mgs] positive ground

[Paul Hunt]

"Have to be" is probably too strong a phrase, "should be" is probably more
appropriate.  It *will* work either way round, and you may not even notice the
difference if connected the 'wrong' way round.  I've seen claims that it only
makes a difference if reversing the polarity of the HT to old plugs, it being
said that having run some time at one polarity they are harder to fire if you
reverse it on the same plugs.  Modern cars with distributor-less ignition
where one coil feeds two plugs in the 'lost spark' system usually have one of
the two plugs at one polarity and the other at the other, so I doubt there is
anything intrinsically 'wrong' with reversing the HT.  The difference on our
cars is the return path for the HT, which doesn't come through the 'can' of
the coil from ground but through the battery and ignition switch to the SW or
+ve terminal of the coil.  Reverse the coil and it will have to pass through
the LT winding as well, which is probably where the recommendation to keep the
polarity correct comes from, as the HT pulse passing through the LT winding
may tend to oppose the LT pulse and so adversely affect the HT pulse.

PaulH.
  ----- Original Message -----
  The coil will work if connected the wrong way round, though? Just not as
well.