I DO wish people wouldn't talk about internal ballasts. A coil is either a
12v coil or a 6v coil regardless of what is inside. An MGB 12v coil
measures about 3 ohms and a 6v coil about 1.5 ohms. A 12v coil should not
have an external ballast or it will give a weak spark, a 6v coil must have
an external ballast or it will burn the points. The external ballast is a
length of resistance-wire contained within the loom.
PaulH.
----- Original Message -----
From: Brent Schwartz <bschwar@uswest.net>
Cc: 'MG Mail list' <mgs@autox.team.net>
Sent: Monday, February 19, 2001 3:43 PM
Subject: Re: Mallory Experts? Help!!
> Neil
>
> I have had more than one experience with incorrect coil and the symptems
> sound similer to what you are describing. I can't guarantee this to be
the
> solution but It has cured a couple of my cars. P.S. even the "experts"
> told me the wrong coil/resistor combination until I tried it myself and
> proved them wrong.
>
> All coils are 6 Volt coils inside. They either have an internal balast
> resisitor (12 Volt) or an external balast resistor (6 Volt) if you take
> a 12 Volt coil and add a ballast resistor then you are only running
> the coil on 3 volts inside and it will not properly energize no matter
> how much dwell you set.
>
> Fortunately this is easy to test. Try a jumper across the ballast
resistor
> esentially taking it out of the circuit and if it runs correctly then you
> know your problem.
>
> Neil Cotty wrote:
>
> > Hi all,
> >
> > I've had a dual point Mallory installed in my V8 along with a Weber 500.
I
> > appear to have some serious timing problems. The car was running
extremely
> > well, but something has gone amiss.
> >
> > I read that you set the dwell of the points individually to 28deg then
the
> > total dwell will be around 32deg. I have set this as it was at 43 when
the
> > misfire started appearing, but I am still experiencing savage misfire
under
> > load with reasonable, and large throttle openings. I have her at 8 deg
at
> > 800rpm. Vacumn connected, the problem is much worse. I think the Mallory
is
> > advancing way too much but can't be sure. The sound is like
> > 'rrrrr-rrrrrrrr-rrrrrrrr' when the misfire appears, almost like a rev
> > limiter or a bad coil. My existing Sport coil was wired up with a
Ballast
> > resistor to support the Mallory unit. I've seen you can adjust the max
> > advance of the Mallory. Any recommendations on how to do this, how to
check
> > it and what to set it at? It looks like the base plate has to come off
at
> > the very least.
> >
> > Stuck here at work, driving home looking very unlikely! :( Any help
> > appreciated! :)
> >
> > Cheers,
> > Neil
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