A few weeks ago I experienced a problem with the distributor-cap, part of which was that the rotor-arm had been catching inside on the electrodes, which was evidenced by lots of metal particles. I couldn't detect any play in the rotor-shaft or misalignment of the components, so it was all cleaned up and put back together. But today, when I had a look at it, it had happened again. This is on a 123, electronic distributor, with the cap and arm as originally supplied, 30,000 miles ago.
I had already bought a genuine Marelli cap and a Fiat-packaged, Marelli rotor-arm for future use. I also dug out my spare cap and arm so that I could do a comparison. It's the genuine parts on the left and my spare, used parts in the middle. There are obvious differences on the Marelli cap, which has a very long carbon-brush, possibly just because it's new. The inner electrodes are moulded into the plastic, whereas on the part supplied with the 123, the electrodes are proud of the casing.
I don't want to risk ruining the brand-new parts until I know what caused the issue, so for the time being I've replaced the cap and arm with my part-used spares.
I might have expected this with a standard distributor, which could have worn out by now. But the 123 is a very precise and well-manufactured component, which I hope I can eliminate as the culprit.
I'm wondering if the spring-strip inside the rotor arm has maybe lost its tension and allowed the arm to fling outwards. As a precaution I've put a bit of masking tape over the rotor shaft before fitting the arm in order to make a tighter fit.
Has anyone got experience of this or ideas of causes which I haven't thought of? I would be particularly interested to know if the same has happened with your 123.
I had already bought a genuine Marelli cap and a Fiat-packaged, Marelli rotor-arm for future use. I also dug out my spare cap and arm so that I could do a comparison. It's the genuine parts on the left and my spare, used parts in the middle. There are obvious differences on the Marelli cap, which has a very long carbon-brush, possibly just because it's new. The inner electrodes are moulded into the plastic, whereas on the part supplied with the 123, the electrodes are proud of the casing.
I don't want to risk ruining the brand-new parts until I know what caused the issue, so for the time being I've replaced the cap and arm with my part-used spares.
I might have expected this with a standard distributor, which could have worn out by now. But the 123 is a very precise and well-manufactured component, which I hope I can eliminate as the culprit.
I'm wondering if the spring-strip inside the rotor arm has maybe lost its tension and allowed the arm to fling outwards. As a precaution I've put a bit of masking tape over the rotor shaft before fitting the arm in order to make a tighter fit.
Has anyone got experience of this or ideas of causes which I haven't thought of? I would be particularly interested to know if the same has happened with your 123.
