I just realized that I didn't edit the last reply so if this comes
through twice, my apologies . Also another thought that crossed my mind
afterwards is that the original parts were made of bakelite, which has a
very high dielectric capability. The replacements are I believe some
sort of plastic, which may not have the same capabilities .
Regards
One possible cause short of breakage would be excess KV ( kilovolt)
demand. . For a little history, in the 50 s and 60s when these cars were
built and designed an ignition system in proper order had a peak kv
availability in the 22-24 kv range . A modern system and coil is
capable of in excess of 60 kv. When available voltages were low any
faults, such as high resistance wires, large plug gaps, excess cap to
rotor clearance , lean mixture etc. became immediately apparent in a
poorly running vehicle. What may well be happening here is that with
modern coils installed and more voltage available they are masking
other faults and the kv demands of the system are exceeding the
dielectric capabilities of the 50s design rotor . Modern fuels may also
be a contributing factor to kv demand . To put that into perspective in
the 80s GM was using a wide plug gap on some of their vehicles, in the
.060 to .080 range, which the ignition system was quite capable of
firing . Rotor burn through was also a common problem . The fix was to
reduce the plug gap to .040. If someone could reinstall one of these
rotors and see if spark is available at the coil wire but not at the
plugs it would verify that in fact rotor burn through has occurred .
It isn't always apparent and visible.
In a similar vein part of kv demand is the rotor to cap gaps , it is
possible that on some rotors the gaps are too high and causing the same
problem., or a wrong shorter 4 cylinder rotor is being used . Of
course it's also a possibility that they are a bunch of cheap Chinese
crap made out of recycled plastic kiddy toys too .
HTH
Regards
John
Bob Brown wrote:
>Payton,
>We are putting up with this because it is possibly not a
>fault of a single manufacturer. Last year on the way to
>Conclave I went thru 3 rotors, that were purchased from
>VB as the "good" ones. They were packaged in boxes labeled
>Bosch, but closer instpection the fine print read "manufactured
>for Bosch in Germany". Thus they were not the "cheap Asian
>imports". After I ran thru my spares the last rotor was
>borrowed from a traveling companion, it was a"cheap Asian
>import" from Moss. That incident occured almost one year
>ago and I'm still using the Moss part.
>I'm convinced it is not solely the rotors but a very had to
>diagnose problem that manifest itself by destroying rotors.
>But no one has suggested anything to look for.
>Bob
>
>Patton Dickson wrote on 6/12/2004, 10:06 PM:
>
> > Why are we putting
> > up with this??? This isn't normal Lucas bad electrics, this is an
> > absolutely defective part sitting on the shelves!
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