The GMC CCKW

Hi can anyone tell me how to test my coil,im not to get with electrics not sure if theres any current coming thro ????? probably something simple

If you have an ohm meter, you can measure the resistance from each terminal to the other and from the high voltage terminal to one of the small terminals.

I am not sure what the resistance will be, but there should be a relatively low resistance on the terminals and a relatively high resistance on the HV output.

Assuming the coil is still on the truck - have you tried pulling one of the HT leads off and attaching a spark plug to it, turn the engine and hold the plug next to the cylinder head, if you dont get a spark and your condenser, points and HT lead are good them your coil maybe bad. I had the same problem recently and had to replace the coil.

primary circuit 1,5 ohm (for 6V instalation)
secondary circuit 8,5 kohm

simple calculation (not sure it is valid)

850 ohms divided by 1.5 ohms = 5666 X 6 = 34000 volts

Seems about right