123 Ignition distributor for SC and 3.3 turbo – potential pinion issue

[hannu_911]

I contacted 123 Ignition two years ago about their products for SC and 3.3 turbo and asked them to correct the following information on their products.
Their web page points correctly to the right product for SC but not for 3.3 turbo.

All 1978-83 SCs and 1978-89 3.3 turbos use the very same CCW gearing for the distributor. So the product on the right does not fit 3.3L Porsche but the one on the left does.

There are also two other points that you should be aware of when considering 123 ignition distributor.

Please look at this Porsche technical note from late 1977.

This distributor drive change on SC and 3.3 turbo took place beginning of November 1977, so very early on model year 1978 production. Thus, there are only very few SC’s and 3.3 turbos with the older distributor drive on crankshaft.
So if someone has one of the very first SCs of 3.3 turbos you should check what pinion your current distributor has and has the drive gear been changed on the crankshaft.

There are two different pinions used from November 1977 onwards as you see from the technical note. At the time when the technical note was written the longer ones were used on engines with catalyst, but later the longer ones were used also on non-catalyst engines. Also some technical notes say that the longer pinion is for SC and shorter for turbo but that is not correct (although could have been correct at the time of writing the note)

Left is 930 602 422 02 pinion from November 1979. (Pinion diameter is 25.9mm. Teeth thickness is 3.15mm)
In the middle is 930 602 422 03 pinion from October 1984. (Pinion diameter is 25.9mm. Teeth thickness is 3.15mm)
On the right is the 123/TUNE+-6-R-V-POR911-3L-SC pinion. (pinion diameter is 24.9mm. Teeth thickness is 2.75mm)

I don’t have a pinion from before November 1977 produced cars to measure teeth thickness. Anyway those are 25.2mm diameter.
I’m speculating that 123 Ignition made their pinion based on the older 911 CW pinion. So they used the same dimensions that older 911s have and only changed CW to CCW.
Could someone who has an older CW distributor check what is the teeth thickness on the pinion?

From the picture you can also see that there is much bigger gap with 123/TUNE pinion than with the original Porsche pinions.

I wonder if this smaller 123/TUNE pinion will wear the distributor drive on crankshaft faster than it should?
Should I buy a new 930 602 422 04 pinion and replace the 123 pinion with that? That would be doable even though the 123 axel is smaller in diameter.

I did ask this from 123 Ignition as well but they did not reply.

It would be also interesting to know if 123 Ignition has changed the pinion on their later SC distributors. At least I see that they have now wider seal, like on the Porsche distributors. Mine has still the thin black seal like you see on my picture.

[zsiegelman]

Hello, wondering if you ever came to any conclusion after this post. Did you end up installing the 123 distributor?