Ian Frearson wrote:
After a brisk ride on the freeway today, I noticed when
looking under the hood that I have the dreaded burning-up
ballast resister, which, as has been described by others, is
smoking like an unattended cigarette. I don’t have any
starting or running problems, and the coil and ballast
resistor are very clean, so it’s definitely not the result
of them being oily or something like that.
After reading through the MANY posts about this issue, I’m
still unclear as to exactly what I need to do
You have three choises, Ian…
Let it smoke; if it burns out - bypass it to get to your destination.
Change ths smoking one to a non-smoker - and move on. Or remove the
damned thing…
The ambiguities in advice is only related to the CE system - for all
other ignition systems the resistor(s) are there for fairly obvious
reasons; aftermarket systems should follow the respective advice given
by the manufacturer.
The ambiguity for the CE advice is that most of us do not gladly deviate
from work manual specs - which include or exclude the resistor depending
on coil type, but without seemingly any rhyme or reason. Ie, why some
coils are mentioned with, and others without, the resistor seems a well
kept secret ex factory - there is no mention of ‘why’…
The resistor drops coil voltage and restricts current flow through the
coil, which affects the spark voltage and spark energy. The ign amp of
the CE varies dwell angles automatically - to maintain a constant spark
energy throughout the rev range. Otherwise the amp is just an electronic
switch; a ‘make’ 'break’ground connection for coil neg - just like the
mechanical points it replaced…
The amp cannot make a silk purse out of a sows ear - it cannot deliver
more out to the spark plugs than the coil/resistor allows to pass.
Rumour has it that excessive current may destroy the amplifier, which
may happen with some coils without the resistor - but for all I know
this is an old wives tale; you can believe it or not…
If there is no running problems with the restricting resistor - there is
no problem either way. And if the engine won’t run with the resistor;
you simply run without it - which most of us do. If the resistor fails
en route, the engine will stop - and the simple expedient is to bypass
it; that will reveal if the cause is the resistor. And if the resistor
smokes it is likely defective anyway…
There is no real data on why Jaguar fitted the resistor to some coils
and not to others on the CE. They may have had a reason - but as it is
not clear why; there is no way of finding out whether an arbitrary coil
actually needs a resistor. Or rather; the coil on the CE system does NOT
need a resistor - whether the ign amp needs it is has no answer…yet…
…the resistor(s) has been in the dustbin a looong time…
Frank
xj6 85 Sov Europe (UK/NZ)>- some say the
ballast resistor is required, some say it’s not needed. And
as to what’s going bad - maybe it’s the ballast
resister…or maybe it’s the coil…how do I even tell? I’m
tempted to replace both to avoid things exploding/catching
on fire.
Can anyone tell me for certain what the correct coil is (the
actual Jaguar part number)? My parts manual says it’s
DAC3001, but then other sources indicate that’s only correct
through 1985. Do I need the ballast resistor? It’s in my
parts manual as C32578, but nowhere else do I see that part
number referenced as correct for a Series III.
===================================================
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