I've posted this over on autoshite as well, but I'm trying to get as many opinions / ideas as possible - I've got a week off work next week and I'm determined I'm going to get the darn thing running...
I've been fighting the ignition system of my Austin Ten for a while now. I just can't get a spark, despite the fact that it was running fine when my mate had it (I saw and heard it running on more than one occasion) and none of the ignition bits had been tampered with between then and my taking it on.
Bear in mind that the car is positive earth, which confuses the heck out of me for a start.
First oddity was that the live feed from the ignition became an earth when the ignition was switched off, which seemed odd to me, unless the ignition switch earths the coil to switch it off rather than just breaking the circuit? For the purposes of testing though, I just ran a live straight from the battery live (-) terminal into the - side of the coil, and then took a wire from the + side of the coil down to the distributor.
The live feed from the coil feeds into the mobile point. The points are opening and closing as they should, and the mobile point is live when the ignition is on; the static point becomes live when the points are closed, so current is obviously getting through the points. I would have thought though that the static point should be earthed somewhere along the line in order to complete the circuit, and it isn't - run the tester from the live battery terminal to the point and it's completely dead. The only thing in the distributor that is earthed is the outer body of the condenser.
The other thing that doesn't seem right is that both low tension terminals on the coil are showing live all the time - I thought that the earth side of the coil should only have current passing through it when the points are closed.
So basically, the points aren't breaking the low tension circuit in the coil so the high tension windings aren't energising - if my understanding of the workings of a coil is correct. The problem is that there is no circuit as such through the points because there's no earth there, so technically it's as if the points were permanently open so the earth side of the coil should be permanently dead, shouldn't it? I've tried wiring the coil up the other way round and it does exactly the same thing. It's the coil off the Skoda so I know it's a good 'un.
Any ideas would be greatly appreciated...
I've been fighting the ignition system of my Austin Ten for a while now. I just can't get a spark, despite the fact that it was running fine when my mate had it (I saw and heard it running on more than one occasion) and none of the ignition bits had been tampered with between then and my taking it on.
Bear in mind that the car is positive earth, which confuses the heck out of me for a start.
First oddity was that the live feed from the ignition became an earth when the ignition was switched off, which seemed odd to me, unless the ignition switch earths the coil to switch it off rather than just breaking the circuit? For the purposes of testing though, I just ran a live straight from the battery live (-) terminal into the - side of the coil, and then took a wire from the + side of the coil down to the distributor.
The live feed from the coil feeds into the mobile point. The points are opening and closing as they should, and the mobile point is live when the ignition is on; the static point becomes live when the points are closed, so current is obviously getting through the points. I would have thought though that the static point should be earthed somewhere along the line in order to complete the circuit, and it isn't - run the tester from the live battery terminal to the point and it's completely dead. The only thing in the distributor that is earthed is the outer body of the condenser.
The other thing that doesn't seem right is that both low tension terminals on the coil are showing live all the time - I thought that the earth side of the coil should only have current passing through it when the points are closed.
So basically, the points aren't breaking the low tension circuit in the coil so the high tension windings aren't energising - if my understanding of the workings of a coil is correct. The problem is that there is no circuit as such through the points because there's no earth there, so technically it's as if the points were permanently open so the earth side of the coil should be permanently dead, shouldn't it? I've tried wiring the coil up the other way round and it does exactly the same thing. It's the coil off the Skoda so I know it's a good 'un.
Any ideas would be greatly appreciated...