Lancia Motor Club

Hi All,
I’m having repeated problems with my engine not running properly.
I’ve had spark plugs stop working, sparks leaking through rubber plug caps and creating a tiny hole in them. I’ve replace the bad spark plugs and the rubber covers.
The engine runs great immediately afterwards but then a couple of days later, after driving the car couple of times for short distances, the engine runs badly again!

Now, in the order of the cylinder firing sequence, cylinders 3, 5 and 6 aren’t firing - (see diagram attached). I can tell because the exhaust manifold branches for these cylinders aren’t getting hot whilst the others are.

I’ve got:
‘Ignition123' Electric Distributor Ignition system
Carbon core HT leads
NGK iridium spark plugs (NGK BKR6EIX 6418 Spark Plug Iridium IX)
Standard spark plug rubber caps.

The position of the cylinders not firing don’t suggest a blocked carb main jet. I’ve had a problem with blocked fuel pipe and/or weak fuel pressure but I’m pretty sure that has been solved now.

Do you think its possible that 123 Ignition system, carbon core HT leads are damaging the spark plugs and rubber caps?

Any other suggestions please?

Would it be worth changing the ignition system back to a points/condenser system  and see if that cures the problem ?
If it does you can then make the electronic ignition the culprit.
Bob

Hi Bob, Thanks for your reply. I'll try that as I've tried everything else.
I managed to get it running on all cylinders after de-carbing the plugs but it has now developed a back fire through the carb on tweaking the throttle. After checking for vacuum leaks, doing tappets, cleaning jets and checking float level its now not firing on one cylinder and still has a back fire even, though less often.
I'm wondering if the 123-Ignition electronic ignition dizzy and Bosch coil are just to strong for the plugs and/or HT leads and doing something to them that makes them stop working intermittantly and then eventually kills them?
Chris