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MG MGB Technical - Lucy won't start

I've got a pertronix ignition ordered to replace the Lucas electronic unit. Lucky I did because today Lucy refused to fire. Engine turns over & thats all.My question: How do you check a coil with an ohm meter ??
Thanks
Don
Don

Depends on ballast type or non-ballast Don but ballast should read 1.5R across the terminals and non-ballast around 3R. rich.
Rich

Actually the coil is TWO internal windings, either of which could be bad, and a ground side that could be open. If the engine will not start and the coil is thought to be bad then BOTH windings and the ground side will have to be tested.
First: Verify there is no spark from the coil by removing the coil wire from the distributer and holding it about 1/4" from the block while cranking the engine. You just might want to use insulated pliers to hold it, or anchor it with a spring-type clothes pin!! (or smile)
Second: If there is no spark, then verify that the points in the distributer are actually opening and closing, Can be done numerous ways, but a dwell reading at the coil (-) terminal will show it. If not, don't forget to test the condenser for grounds.
Last: Check the resistance from the coil (+) to (-) terminals AND the resistance from the coil (+) and then the (-) to inside the center tower. None of these should read infinity. They should all be in the 0 to 1.5 or so Ohms.
Tom

I just checked the resistance on two coils both are 12 volt coils, one Lucas and a Bosch Blue coil. + or - to center high tension lead is around 5.6k ohms on the Lucas and 9.5k ohms on the Bosch.
Don is replacing an OE electronic coil so I assume he has a 6 volt coil, + to - should be around 1.5 ohms.
Clifton
Clifton Gordon

Should read

"Don is replacing an OE electronic ignition so I assume he has a 6 volt coil, + to - should be around 1.5 ohms."

Clifton
Clifton Gordon

This thread was discussed between 27/03/2005 and 28/03/2005

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