Ignition fault finding

[John Mason]

Peter, because your car was running ok before your breakdown and the points gap moving being the fault I think it is something simple that has been overlooked and the more parts you replace the harder it is to locate what's wrong. I would start from scratch again first with re checking your points ( see if you have assembled them together correctly) and doing that bulb check. Check the rotor arm is correctly on the drive and that the button in the  dizzy cap will make contact with the rotor when fitted. Finally take a plug out re connect the lead and lay it on the engine block where it will make contact to earth. With ignition switched on turn the engine over a few times to see if ther is any spark (this can be seen easier in the dark). If no spark work backwards towards the dizzy and coil.
One other thing you might wish to check is your engine to body earth good. Remember plugs rely on a good earth tocomplete the circuit.

John Mason

[Peter Naulls]

Thank you all for your excellent advice. Following Dave, Simon and John's suggestions I connected a plug directly to the coil, bypassed both low tension terminal wires and got a good fat spark.  From there I narrowed it down to the distributor not switching the earth. Everything came apart again including this time removing the little curved strap which joins the points to the end of the condenser. I cleaned the base plate and all the terminals, replaced nuts and lock-washers with new and, once back together it works fine.

I don't quite understand why changing the base plate didn't cure it before but no matter. As a precaution I will replace the LT wire from the distributor back to the coil. In the meantime I took the car for a brief (and very chilly) run round the block. Smiling once again.

   

[Ruairidh Dunford]

The new rad. cowl looks great Peter - not actually seen it on the car before.

[John Mason]

Peter, because your car was running ok before your breakdown and the points gap moving being the fault I think it is something simple that has been overlooked and the more parts you replace the harder it is to locate what's wrong. I would start from scratch again first with re checking your points ( see if you have assembled them together correctly) and doing that bulb check. Check the rotor arm is correctly on the drive and that the button in the  dizzy cap will make contact with the rotor when fitted. Finally take a plug out re connect the lead and lay it on the engine block where it will make contact to earth. With ignition switched on turn the engine over a few times to see if ther is any spark (this can be seen easier in the dark). If no spark work backwards towards the dizzy and coil.
One other thing you might wish to check is your engine to body earth good. Remember plugs rely on a good earth tocomplete the circuit.

John Mason

[andrew34ruby]

Andrew, I disconnected the coil and put a voltmeter (rather than a bulb) across the low tension wires. 

Peter.

Why? For this test a bulb gives you a diagnosis far better.