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Helping out Gero, a packard friend over here. I translated this for him, but have never personally timed a dual point distributor. What is a Synchronoscope?
From what I understand, he should be able to use a normal timing gun on cyl 1 for one set of points that are fixed to the disributor, and then on cyl 6 to set the timing of the second set of points that can be moved relative to the distributor.
Also, is 5 deg at idle and then 25 degrees maximum at speed on the flywheel or damper the correct end points for ignition?
Thanks, happy Easter and stay healthy!

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IIRC, the 120Bs had a conventional single coil and eight lobe distributor. Timing is set using No. 1 cylinder. They may have had a distributor without a vacuum modulator chamber. The instructions are most likely for a senior eight engine. Others here may know more about this.

Dual point distributor info, not necessarily Packard related. I spent many years dealing with dual points but they were all related to high performance applications.The theory was more dwell time equals a hotter spark. One set of points would close and begin the coil saturation phase and the second set would close a fraction later. Then, the first set would open but the spark would only occur after the second set of points opened. Thus the total dwell time was increased. I can't visualize how two sets of points could fire different cylinders. Bob

Bob, in case you were unaware, I just wanted to point an exception to your comments; the 1933-34 Packard Eight and Super 8 used a Northeast distributor with dual points but a 4-lobe distributor cam. Thus each point set individually controlled 4 cylinders thru dual coils and a duplex rotor and therefore had the dwell characteristic of a 4 cylinder engine. That system was abandoned after 1934, the elegance and performance probably didn't justify the extra cost. And perhaps the purchase of NorthEast by Delco was a factor.

To set timing you can rotate distributor until you get maximum vacuum reading on a vacuum gauge at idles. Then take it for a drive and see if it pings under loaded and retard a bit at a time until it stops pinging.

Thanks
James From
Kanter Auto Products

I believe Gero's car has the 4 lobe dual point distributor. And James, your procedure is certainly the best way to get the timing as early as possible for the best vac at idle, but then back off if there is pinging at load in high gear up hill.
Thanks for the advice. I will relay to Gero.

-With these dual point distributors: I understand that one set of points is adjusted by rotating the distributor, and the second set is somehow adjusted by moving the points inside the distributor? Is that right?

-Then with the "fuel compensator" you can then add or subtract a few degrees advance accordingly.
-I Appreciate you all helping me help Gero.

I doubt it has 4-lobe distributor. Most likely an 8-lobe, dual point distributor as described by toymanbob.

Back in the day dual point breaker plates were available and installed to enhance ignition output and lessen point wear. My guess is one of these after market dual point breaker plates has been installed sometime in the past. Each point set is set to a normal gap of .016" or thereabouts and the timing checked in the usual manner using No. 1 cylinder.

A 4-lobe distributor - dual coil ignition system would be something very unusual on a junior 120. Let us know how this turns out.

Shows you how much I know about this....Gero sent us a few pictures. It does have one coil, so I guess it must be an 8 lobe cam converted to dual points? I think I can even see that the points are worn from here. The top left set of points in the one picure looks to be closed, but not parallel. Oi vey.

So would setting point gap and dwell be best done with a dwell meter? 30 degrees is standard for an 8 cyl engine from what I just googled. -now I question if the 0.018 to 0.022 point gap listed in the owners manual is still fitting for this modified distributor. Any suggestion for point gap? (Sorry JW, just re-read your suggestion of 0.016)

Then setting timing is just done like any old normal single point distributor is done? Timing light on cyl 1 and then max vac at idle and then check for pinging under load? -6 degrees at Idle as a starting point.

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All 35-36 8 cyl 120's had an 8 lobe dual point distributor

Thanks
James From
Kanter Auto Products

Two ways to set the points gap.

(1) use a feeler gauge. Set each set to specified gap or .016" to .018".

(2) use a dwell meter. Place a thin piece of cardboard or thick paper between the contact areas to disable one of the points set and set the other to 30 deg. Then repeat on the other set. Overall dwell with both sets working will now be around 35 deg.

Also note that these Autolite distributors besides being fitted with dual points did not have a vacuum modulator chamber. Autolite distributors often featured dual points (e.g., 1950s Chrysler V-8s).

This has been fun and I hope informative.

Take care and stay well.