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Peetee
Minor Legend
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all coiled up!

Post by Peetee »

I have just recently learned there are two types of coil; ballasted and non-ballasted. What's the difference? I moved my coil from 'lying down' to 'stood up' when I fitted an alternator. Am I heading for trouble?
Ta
Older and more confused than I could ever imagine possible.
Willie
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coils

Post by Willie »

No, mounting the coil differently should have no repercussions.
A ballasted coil supplies a higher voltage during the 'starting'
period which drops once the engine is running. You should not
try to fit one to the Minor.
Willie
newagetraveller
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Post by newagetraveller »

A ballasted coil is designed to be used in series with a 'ballast' resistor.
While the engine is being started the ballast resistor is shorted out and the 12 volts from the battery is applied directly across the coil. This provides a higher voltage at the spark plug to make starting easier.
Once the engine is running the 12 volts supply is connected across the series combination of coil and resistor and hence the voltage across the coil is lower.
If a coil designed for a ballasted system was connected in a Morris Minor I would expect the engine to start well and run for a short while. After this the coil would probably heat up and burn out.
Cam
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Post by Cam »

Stick with your original coil, if all you have changed is the charging system.

You can only fit a ballasted coil to the minor IF you fit the ballast resistor as well (in the form of a high resistance wire or ceramic resistor) and re-wire the starting circut to short the resistance wire out as newagetraveller explains.

If you intend to do this then the easiest route is to take the system off an '80s Mini, but it is really not worth the bother, as the standard Minor non-ballast system is perfectly adequate, even when used with high performance engines!!

Incidently, my coil is now standing upright, and it seems to perform (as it should) the same as it did lying down. I have run it like this for over 12 months, so I would not worry.
an_avenger
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Post by an_avenger »

Is there a code which determines 'ballasted' and 'non-ballasted' I bought a new coil and want to check that it's the right one, just as a precaution!
Cam
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Post by Cam »

I would imagine that there are bound to be reference codes but these might only be available to motor factors - unless anyone else has a list??

You can check for yourself if you measure the primary winding resistance (+ to - on the coil) and compare it with the value stated in your workshop manual.

Or if you have a few coils as a reference, the non-ballast type should read higher resistance than the ballast type.
newagetraveller
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Post by newagetraveller »

Most of the lists of electrical components are on the internet.
Try typing the code into a search engine such as Google.
It will usually find the list for you.
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