could it be the condensor?

Hello Mick

The condensor, points, rotor arm, ditributor cap & HT leads were all replaced last year. The distributor cap interior is dry but there was plenty of evidence of arcing. If the problem was due to any of these items wouldn't the failure be consistant at whatever the engine revs were?

It's possible I may have an air leak. This might account for the problem when reving the engine. ie. weaker fuel/air mixture as the revs increased.

Other possibilities I'm exploring are a partial fuel blockage or even poor quality fuel. Either way I'd rather have had the problem in the winter than mid-summer.

Mnay thanks for your suggestion.

Regards
Mike

Hi Mike.

Can you clarify the timing figures, please?

I presume it was set at 10 degrees BEFORE TDC at idle (or static?) initially. How exactly does this change when you rev the car?

If you have signs of arcing inside the cap, you clearly have an ignition problem - I don't see sticky valves or mixture doing this.

Incidentally, I had a TINY air leak on my inlet manifold last year on my Ford Pinto-engined Marlin, and the symptoms were that it wouldn't run BELOW 1500rpm (the engine speed would rise and fall like someone was 'blipping' the throttle), but it was fairly ok above that speed - so pretty much the exact opposite of what you are experiencing!

I wonder if a 'bob-weight' spring has broken/slipped off which would cause the timing to advance excessively, and too soon?

Do yourself a favour and change the condenser. I have just spent money and a lot of time changing to an unleaded head (which needed to be done sometime) only to find the problem of backfiring persisted. A new condenser cost me £3.50 and problem solved. The old condenser was in a distributor which I bought as a recon
only a yearYGYA or two ago.

David

I will get another one. I have found that replacement parts like indicator flasher relays don't last very long.

Many thanks for advice. I'll update this Post when I solve the problem.

Regards
Miek

Donnie

Yes 10 degrees before TDC. The misfire caused a 10 degree after TDC reading (strobe light).

I'll be replacing the distributor condenser over the coming weekend.

Yes, you are right - complete opposite. It will something else then.

Regards
Mike

Hi all

I had a very similar problem and it was the rotor arm. The arm fitted was brand new, put an old one in and been fine ever since. I was talking to Dennis Roberts @ Donington last year and he has had similar experiences. I now carry a spare!!
HTH
Mark

I wonder if fitting electronic ignition might help ensure against future issues once fixed?

Ashley.

All

Many thanks for suggestions on Rotor Arm and electronic ignition. Hopefully I find a solution this weekend!

Regards
Mike

Hi Mike.

Very curious as to how you got on - and what the culprit was!