More work on UNJ and it's getting very satisfying now.
The car has been running fine but a hint of the misfire had returned, little things like faltering on the overrun, needing third gear at 30mph and 4th at 50mph. Then there was a fair amount of "pinking" if accelerating and putting the engine under a bit of load.
"It's always the ignition side" is my favourite saying to guide me under these circumstances but just on the off chance I checked the carb balance just in case one pair of cylinders were not getting the same fuelling as the other which would also cause the above. No, using the special tool of a length of fuel pipe stuck in my ear and then into the carbs in succession all was well there.
So, over to the ignition side.
With the engine warm and at tickover (which is also high at about 1200rpm) I pulled the plug leads off one by one using my special insulated grips and number 2 was making no contribution at all! Then testing with a spare plug showed no spark from this plug lead so I inspected it further and found the connector at the distributor cap end broken.
I didn't have a spare lead but managed to fix this with an end from an old lead. At the same time I put a small amount of grease on the distributor cam and lubricated it, along with cleaning up the dizzy cap.
The car performed much better on the next test run with much reduced pinking and no hesitation present so hopefully I have made a permanent cure. It's pretty good how well the car ran before though considering the poor/non existant input from number 2 cylinder.
This also gave me the chance to adjust the tickover speed and I was able to reduce it now to 850rpm but it does seem very reluctant to keep returning to this. Moving the loation of the throttle return spring helped as did oiling of the linkages. More use might help and the car is certaily going to get it with the International AutoEcosse next weekend.