the mk1 kid

Hi chaps,

A carb'd pinto in my friends kit car is sick (arrrgh), and i think, from all the tests we have done the coil is dead. Strangely we have a spare, and that isn't any help either.

The starter had died while the car has been stood, but thanks to a garage find that is now sorted.

(Pictures will follow a little later)

It has, and started previously with:

New leads, cap, points etc, but we cannot get a spark, and the earth on the points is 9v - so i guess the ballast resistor (if that is what it is) works as it should...

When i get the pics up i'll ask some questions, and double check some basics...

Cheers
Tom

PS there is no 'loom' as such, just short cables for testing purposes (he has a custom one in his loft ready to fit), so there is no issue with earths (checked a million times), or power feed/wiring...

S1

What voltage do you have at the coil when cranking as it should bypass the ballast resistor to account for the voltage drop?

the mk1 kid

We haven't (as far as i remember) tested it while cranking. Both of us are pretty unfamiliar with older motors, and the resto has been spread out, with many months in between...

I know we have full juice at the coil, and 12v (or so) droppping quickly to hold 9v the other side of the points.

I checked the coil before work and it says 1.5ohms and mentioned the ballast resistor on it.

Q, is the ballast resistor the thing on the side of the dizzy - it looks more like a capacitor?

When i googled BR this moring they dont look anything like this...

Q, Should we be able to get a single spark from the coil with an HT lead and plug directly into it (threads earthed obviously), upon first connecting it? I know without points it wont continually spark, but i'm sure from memory, and just thinking about it, it should spark the once. If 'Yes' it would rule out the BR, and anything to do with the dizzy (which is new, and cleaner than my dinner plates)...

Many thanks
Tom

S1

The thing on the side of the dizzy is the condensor, its function is to encourage the coil to discharge the spark in one go rather than a drawn-out discharge. The ballast resistor is in the positive feed to the coil from the ingition switch. There should be another feed to the + coil which is live during cranking only.

Have a look at this circuit diagram, it should clear things up.

http://www.hotrod.com/pitstop/hrdp_1.../photo_02.html

the mk1 kid

Of course it is - i remember now!! Thank you.

Well my mate swears he started the pinto (after replacing the 1300 crossflow) withouth the main loom, on just the short wires present now for testing purposes.

If the coil, which says 1.5 ohms is to be used with the resistor that presumably should be on his old loom.. hmm

Would the coil therefore not produce a spark at all if it was designed to be used in conjunction with the BR?

Cheers
Tom

PS reading link now - thanks

bunnymofo

heres the pics, sorry it took a while i was bizy..

the mk1 kid

No need to apologise - thank you for being such a gent!

So if anyone knows whether the lack of (if it should have one) a ballast resistor would actually prevent any spark at all, please shout.

If the coil is 1.5ohms, and mentions a BR (pic quality if terrible, sorry) would this not suggest it should have one?

Cheers
Tom

the mk1 kid

Hi,

Thank you for your link, i've read it now.

We are obviously missing the ballast resistor (it must be on the main loom), but that shouldn't make any odds as the engine is not running - eg it is 'cranking only'.

I *think* the coil is fubard, and thus it needs a new one, question is, should it be one that is design to be used with a ballast resistor or not - considering the kit car will have a custom loom?

Cheers
Tom

bunnymofo

no bother :P