Turns out it was the condenser!

[jjad]

Our GTL had started to judder occasionally, which got worse and worse, especially up hills. It would idle fine. The points gap (on new points) was OK, the vacuum advance mechanism was working (checked by sucking on the tube), fuel filter was clean, coil resistance was OK, HT leads (fairly new) were all OK. There didn't appear to be a leak on the inlet manifold or base of carb (tested with WD40 when engine was running).

Had the carb cleaned by local garage, but was still running badly. Finally they replaced the condenser (and put in new points) and now he's running perfectly again. I only fitted the condenser less than 2 years ago.

So, if you've got ignition problems, it might be the condenser after all!

Happy driving

 

[malcolm]

These days the quality of new ignition components for old cars doesn't seem so good. I had trouble with a rotor arm on my MG which took me a whole year to diagnose. The problem was it only caused problems when it was hot, but it wasn't hot in the garage when I was investigating the problem.

I don't know the answer - old stock has mostly dried up so you can't fit an original part.

 

[jjad]

It was a BOUGICORD 160225 condenser from Mister Auto. The HT leads were also BOUGICORD, but the cap, rotor and points were VALEO.