Gregory Bender

Distributor dual points plate modification so you can time both cylinders properly

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Thanks to Greg Field for posting this information on the Wildgoose Chase forum on . In Greg's own words:

Manufacturing tolerances on points plates for dual-point timers often mean you have to choose one of the following: Equal points gaps OR the same timing on both cylinders. Usually, the left cylinder adjustments hits its stops before you can retard it enough to match the timing and gap of the right cylinder, unless you make the changes shown here:

First, remove the entire plate and then the screws holding on the movable plate. Move the plate through its limits and see what stops retardation first. Usually, it is the boss on the back of the plate for the stud for the LH points.

Here's a view of the back of a partially modified plate. Look how oval-filed the holes highlighted in blue are. As I filed one, another would then limit retardation. I was able to file a bit more than shown here before the slots for the screws that affix the movable plate reached their limit.

Modifying dual-point plates so you can time both cylinders properly.
Modifying dual-point plates so you can time both cylinders properly.

Photo courtesy of Greg Field.

Once the screw slots are at their limit, file a little more on the holes previously filed, and then file as much as you can on the slots. As you can see, there's not much meat to file away from the slot near the point of the file.

Once you've taken the back holes and screw slots to their limit, the two raised humps shown below may be the limit. File off their leading edges until they no longer are the limit, giving maximum possible lattitude to retard the left cylinder.

Modifying dual-point plates so you can time both cylinders properly.
Modifying dual-point plates so you can time both cylinders properly.

Photo courtesy of Greg Field.

Here's what you end up with: LH points that are retardable enough to set them properly. On this particular set, I can retard the LH points 6 degrees more than the RH points. Takes 10 minutes or so.

Modifying dual-point plates so you can time both cylinders properly.
Modifying dual-point plates so you can time both cylinders properly.

Photo courtesy of Greg Field.