On Tue, 12 Jan 1999, John Cowan wrote:
> I unthinkingly pulled the high tension ignition wire out of the
> top of the coil on my '60 TR-3A. Then I unscrewed the plastic nut
> that surrounds the wire. I big chunk of the threaded part was gone -
> perhaps a third of its circumference, up to about half its length. I
> expected to find the broken piece sitting in the coil, but did not.
> The plastic nut appears to have been abraded away, but the threads in
> the coil seem ok.
> I theorize that the lead was not inserted far enough into the
> coil to make good electrical contact and there was sparking going on
> there. Anyone encountered this problem before?
> In any case, this is a miserable design. Anyone have a strategy
> for preparing this connection properly?
Actually it's a very sound design. If you could pull the HT cable out
without unscrewing the wire nut, then it wasn't put together correctly in
the first place.
If the nut is too short, then it is probably one meant for use in a Lucas
distributor. The one in the coil is longer. The HT cable must have a
stranded copper core. Carbon-core resistance cable won't work. There is
also supposed to be a copper-plated steel washer in the assembly, but it's
often missing. The center hole is only large enough for the cable's
copper conductor to pass through. The outside diameter is just a bit
smaller than the threaded hole in the coil. It's split and sprung like a
lock washer.
o Cut back cable insulation to expose about 1/4 inch of copper
conductor.
o Insert cable through wire nut.
o Insert copper conductor through washer.
o Spread strands of copper conductor evenly across face of washer.
o Screw assembly into coil.
This clamps the washer and copper conductor strands between the wire nut
and the distributor post. The spring action of the washer acts as a lock
washer to keep the wire nut from unscrewing due to vibration. The same
assembly applies for the HT connections at the distributor if the cap is
the type with wire nuts.
Put it together correctly and I guarantee you'll have to yank pretty hard
on an HT cable to pull it out.
-----------------------------------------------------------------------
Chip Old 1948 M.G. TC TC6710 NEMGTR #2271
Cub Hill, Maryland 1962 Triumph TR4 CT3154LO
fold@bcpl.net
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