Side note- with the stronger spark of the electronic unit and new coil, you can also widen the spark gap notably.

Hutbed said:

Side note- with the stronger spark of the electronic unit and new coil, you can also widen the spark gap notably.

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Notably to what size gap?...…


I did notice when I put the A1 unit in and ran the 126 dizzy and coil the spark plug crack was quite impressive compared to the 495cc dizzy cap version....

If I remember correctly, I jumped it up all the way from the workshop manual max spec of .023 inches to .040 inches. It did so well I haven't pulled the plugs out since.

Another installment in my continuous investigation into the vagaries of ignition-timing specs. for the little Fiat engines.

I was looking through the Haynes manual at the detailed specification pages for the post 1985 126 engine. The Haynes manuals have been found to be wrong at times but the specs. are listed quite convncingly. The first change from the perceived wisdom is that the initial timing of 10 degrees is not made on a static engine but measured at 700rpm (idle speed).

There is an intermediate advance of 14 degrees at 3,000rpm.

The maximum advance of 21 degrees is measured at 3,850rpm.

Assuming that the last two figures are additive to the initial timing, that would take the maximum advance to 31 rather than 28 degrees as I have always adhered to previously. This might be relevant on an engine with the factory distributor if you are checking it with a strobe.

But with the 123 I have fitted there isn't any setting amongst the 12 curves vaunted, which exactly fits this shape. In fact, the degrees advanced for each setting are specified at 2,000 and then 3,000rpm and go no further.

My engine runs so well I'm loathe to tinker. But I'm committed addicted to tinkering, so as an experiment, "tuning-curves groups 3 and 4" here I come.

So with a 123 electric ignition it should be 28 degrees btdc and if you have the original points based system it should be 18 degrees?

No still 28 or even more than 30 with modern fuel etc. Mine is close to 32 adjusted by ear.

gordinir8 said:

No still 28 or even more than 30 with modern fuel etc. Mine is close to 32 adjusted by ear.

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Thanks. A few older threads on here were quoting 10 degrees static and then 18 for dynamic timing but I guess they're incorrect and didn't combine the two figures..

Remember that in the end of the day what matters is your ear since there are lot of factors behind standard factory settings like the fuel which is better today, condition of the distributor, engine and so on. So you can have a basic setting at 28 degrees and take it from there.

Bubins said:

So with a 123 electric ignition it should be 28 degrees btdc and if you have the original points based system it should be 18 degrees?

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If your 123 distributor is on the basic setting, referred to in the manual as "0", the actual timing at higher RPM. should be checked and set by strobe and adjusted to 28 degrees BTDC by rotating the distributor appropriately.

Unlike the original distributor, you should not simply rotate it a bit more to get extra advance or retard. The way to effect a different total or dynamic advance is by selecting the appropriate curve by rotating the tiny and inaccessible dial hidden under the allen-screw under the base. Doing this is a PITA and the distributor has to come out.

If you do adjust the maximum advance by rotating the 123, you will mess up the static advance and disrupt the correct advance at every stage of the advance curve.

fiat500 said:

If your 123 distributor is on the basic setting, referred to in the manual as "0", the actual timing at higher RPM. should be checked and set by strobe and adjusted to 28 degrees BTDC by rotating the distributor appropriately.

Unlike the original distributor, you should not simply rotate it a bit more to get extra advance or retard. The way to effect a different total or dynamic advance is by selecting the appropriate curve by rotating the tiny and inaccessible dial hidden under the allen-screw under the base. Doing this is a PITA and the distributor has to come out.

If you do adjust the maximum advance by rotating the 123, you will mess up the static advance and disrupt the correct advance at every stage of the advance curve.

Click to expand...

I have the original points system so that seems quite a bit easier. Waiting for the strobe light to arrive so I can check.