No spark.

[AustinWood]

I would first check if the coil is generating a spark. Disconnect the king lead from the distributor (The one in the middle). Lodge it close to an earth, perhaps a head nut. Then, with the ignition on open and close the points in the distributor. I use a small screwdriver. Every time the points open the king lead should spark. If it doesn't then either there is no supply to the distributor or the coil is dead.
If that works reconnect everything and remove a spark plug and lay it on the engine. Crank the engine with the ignition on. The plug should spark. Might need to be in shadow to see it. If it doesn't then the problem is in the distributor. Maybe points, condenser, rotor arm or distributor cap.

[Ray White]

Thanks all. I can't do anything until I get a new battery. I will of course report back with any news.

Ray.

[andrew34ruby]

Thanks all.  I can't do anything until I get a new battery. I will of course report back with any news.

Ray.

Ray you can use a meter to measure coil resistance. No need for a battery to do that.

[Ray White]

Hello Andrew.  I think I may have resolved the problem but I won't know for sure until later.  The coil is O.K. It shows a primary resistance  of 1.4 Ohms  which is what it always has done.  I think the reason for no HT spark is because of corrosion.  When I removed the king lead from the coil it was all in a sorry state.  I removed the coil and spent a while cleaning up the outlet and the HT contact area.  I then tested it and found I could get a spark using my battery which I had charged up again.  I have cleaned the points and checked all the connections.

After tea I will see if I can coax Trundles back into life. 

[Ray White]

I have now installed a new battery and thoroughly cleaned the coil HT opening. I can get a spark from the king lead against the head if I flick the points... but there is nothing at the plugs or end of leads. The rotor arm is rotating and looks like it is making contact in the centre of the cap.

I presumed there was some points resistance and have cleaned them up with some fine abrasive paper. I checked the plugs and lead ends but can see nothing obvious.

I am not sure if a duff condensorl will stop sparks like this?

As has been stated it looks like a dead short somewhere.??

What could have happened while the car was unused for a few months.?

Still puzzled,

Ray.

[Mike Costigan]

I have just had to replace the condenser which failed immediately following several months of inactivity. But the symptoms were not complete failure - the engine would start and run when cold, but would not respond under load.

[Ray White]

I have just had to replace the condenser which failed immediately following several months of inactivity. But the symptoms were not complete failure - the engine would start and run when cold, but would not respond under load.

Hello Mike.  Yes, that is what I thought.  In my experience a faulty condenser usually causes problems with running rather than prevent starting.  Likewise, a coil may play up when it gets hot.  I might have to remove the distributor and go through it on the bench.  

Your advise would be welcome.

Thanks,
Ray.

[Ray White]

One thing I have noticed is that when the ignition is switched on there is no movement from the ammeter needle. I am used to seeing a reassuring wiggle of the needle when I switch on ...but now, nothing.

This is where the electrics gets above my pay grade....

[A G Wood]

Your advise would be welcome.
My 10 cents:
-definitely 4.5v or better at the coil primary during crank (If you're using the electric one not the human one)
-No movement from ammeter would be normal if the points happen to be open. A cause for concern if they're closed.
-Fig 77: Rotor shorted to earth?
-I don't personally set much store by spark plugs/leads sparking in open air. I have a modified extended nose plug with no earth electrode I use for that job to simulate the influence of compression on the HT voltage for roadside tests, but I've never tried it on a 6v system.
-You may still have a weak coil which is incapable of producing enough HT to jump the added gap between the rotor and the cap electrodes.
-The capacitor, in addition to damping down sparking at the points, also acts as part of a resonant circuit with the coil windings causing 'ringing' which acts to increase the spark duration. So a capacitor issue can cause starting issues when the demand for HT is greatest.

You may have to start with substitution-based diagnosis, as always beginning with the least expensive component of course.

[andrew34ruby]

 I can get a spark from the king lead against the head if I flick the points... but there is nothing at the plugs or end of leads.  The rotor arm is rotating and looks like it is making contact in the centre of the cap. 



I am not sure if a duff condensorl will stop sparks like this? 

As has been stated it looks like a dead short somewhere.??

A duff condensor affects the ability to create a good spark. Various things are possible.

But this sounds like a dead short in the rotor arm. 

Hold the king lead near the head and spin the engine on the starter. You should get a cracking lively spark. Then with the rotor arm in place hold the king lead near the rotor arm and spin the engine. You should get no spark jumping to the rotor arm. If you get a good spark jumping to the rotor arm then there is a dead short within the rotor arm, and it needs a new one.