A coil is either a 12v coil or a 6v coil. If it is 6v coil used on a 12v
system then an external ballast - usually a length of resistance wire
contained within the loom - is required. Whether a coil has an internal
ballast or not is completely immaterial, it is the coil spec that is
important. The MGB coils were 12v (HA12) with a resistance of about 3.2
ohms up until 1974-ish (in the UK, at least). Thereafter the 6v coil was
used ( 16C6) with a resistance of about 1.5 ohms. The ballast wire starts
off as a white at the fuse block/ignition relay end and becomes a
white/green at the coil, extended on to a special contact on the solenoid
which delivers 12v during cranking.
Haynes refers to the 6v coil as "16C6 (6 volt with ballast resistor)" and
this *definitely* refers to the external ballast, not any internal ballast
that might or might not be present.
Forget the issue of internal ballast, an MGA requires a 12v coil.
PaulH.
http://freespace.virgin.net/paul.hunt1/
(or if that URL doesn't work try )
(http://194.168.54.52/paul.hunt1)
-----Original Message-----
From: Neil Cotty <neilc@tradesrv.com.au>
To: mgs@autox.team.net <mgs@autox.team.net>
Date: 17 August 1999 05:20
Subject: Coil Question
>Hi all,
>
>Getting my new Bosch dist. tomorrow so I decided to replace the one I took
>from my MGB which is 29yrs old with a Sport coil type. Bosch have just
>re-released their GT40 in the round style so I won't have to go drillin'
>holes in the A to fit their new funky shaped one.
>
>The Bosch catalog says the MGA requires a coil WITH a ballast resistor.
>Surely this isn't right. The one I took off my A was a Lucas HA12, and the
>one off the MGB (70) didn't use a Ballast resistor either. Can someone just
>clarify that for me that I need one WITHOUT a ballast resistor. I'm 99%
sure
>I'm right, just don't want to order till I'm 100%..! <G> :)
>
>Cheers,
>Neil.
>
>
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