hi can you measure to see if the coil is goosed by measuring the resistance? any help will be greatly appreciated cheers ben
Yes. A HAynes manual will tell you what the resistance should be around the primary coil.
If in doubt, replace it. Youll be chasing your tail otherwise.
I suspected the coil, but changed it last after changing the plugs, leads, points, condenser, then coil.
firstly you are talking old fashion coil and not coil pack?
with coil, disconnect all wiringto it amd measure resistance across low tension side, between + and - terminals.
this should be 3 ohm for non ballast coil and 1.5 for ballast coil.
remove lead from + terminal and put lead into the central HT terminal, resistance should be several K ir not tens of K Ohm.
obviously readings of 0 ohm = short circuit or off the scale = open circuit, mean coils is buggered.
Bear in mind coils can seem ok when cold but when hot, due to expansion of stuff inside can fail but if they fail the cold test, then definetley
buggered.
Do not attempt to take coil apart as they are full of nasty oil.
hi yeh its an old fashioned coil for a pinto with electronic dizzy, sorry for being thick but whats the difference between a ballast/non-ballast coil cheers ben
ballast coil has lower resistance and is designed to work on 9 V.
this is to improve starting, since when cranking the engine over, the battery voltage can drop several volts below 12 V.
in order to prevent the coil getting too hot and buring out when runing, a resistor - looks like a thick piece of wire in the loom - is switched
in.
obviously when cranking, the ballast resistor is switched out. this was introduced to a lot of cars in the 1970s.
non ballast pre-dates that and has coil connected directly to 12 v.
quote:
Originally posted by 02GF74
this should be 3 ohm for non ballast coil and 1.5 for ballast coil.