Runs Rough When Warm

[T100SS]

I've looked through the forum but may be slightly off-topic as this is one of those peculiar problems. The car starts OK but runs rough - like a misfire - when warm.

I checked fuel delivery (and for air bubbles) which is all OK. The carb was then dismantled and some rusty deposit cleaned out, but the jet is clear, plunger oil is topped up and there are no manifold leaks. All other things (fuel cap vent etc) fuel wise seem in order.

I then checked the ignition points, as a previous episode of the same symptoms had caused me to replace the dizzy cap, rotor and leads. They seemed to be way too wide, so I reset them at 15 thou. It ran fine so i parked it up, but next day the syptoms returned and worsened as I drove.

After a second carb strip which revelaed no problems there, I found the points had closed up, so I reset them again. It ran ok until warm and the stuttering returned. It occurs to me the previous owner suffered this as he had put new plugs in before letting me collect it. Also, previous experience with a 40 year old motor tells me the distrubutor shaft may be worn. This is a mystical problem, which can cause you to blame other components as the cause is dificult to detect -things seems normal (like points gaps etc) and the nature of the fault hides itself. So before I get a replacement distributor, has anyone any suggestions as to what this may be?

The car ran fine when I bought it but went doolally shortly after. I fixed it (according to the manual revving it with hand over carb clears the jet) and it ran good for a few weeks. I tried this method again and it didn't work, hence other investigations

[MarkyB]

Check the tappets?

[mike.perry]

If the distributor shaft is worn then you should be able to wobble it by hand

[bmcecosse]

Try a new condenser....

[T100SS]

Ah, these posts are running away with me. I replaced the Dizzy as it wiggled:)
thanks

[bmcecosse]

And did that fix it??

[T100SS]

A bit pointless now, but I hate loose ends, yes the new distributor fixed the running.

That said the timing never seems quite right. At least it pulls now and doesn't stutter on after the ignition is turned off either:)

I have since learned that the cheapo replacements may not have the right dwell. The points (red plastic) are rubbish - I've adjusted them about three times and filed them over in the last year. The 'Lucas' points on the tig are still bright and spot on, and I never had to fiddle so much except on an old BSA - the Woodruff key was gone on the cam so timing was a case of ride & adjust:)

Thanks for all your replies over the months. Might have a bash at the brakes tommorrow.