Packard Forum Index » Post-War (1946-54)

Good to try the "Ross Method" first. It is simple and cheap, and results will present themselves quickly. That said, tuning a distributor is mostly a lost art these days.

Vacuum advance chambers are used across a number of applications for a given manufacturer. What differs in them is the length and/or tension of the spring. That is why it important to remove these items from the chamber when sending in a defective unit to exchange for a rebuilt one. Using shims can affect the amount of advance too.

The automatic or mechanical or centrifugal advance mechanism can also be tuned for the engine speed in which it starts to advance, how quickly it advances (the advance curve), and how much it advances.

Breaker point gap or dwell will affect ignition timing. The timing will retard over miles as the rubbing block wears - gap decreases, or dwell increases.

Tuning a distributor is done on a specialized machine that mounts the distributor and has various gauges and other attachments. The operation of the vacuum and mechanical advance can be observed directly. It was used back in the day by better shops to set new points and check the distributor for proper operation and check for wear.

(o{}o)

Another option may be running a cooler heat range spark plug.

Thanks, JW and BigKev. I don't think I'd pursue sending the distributor out with the engine running as well as it does and the ping so intermittent. Cooler plugs are a good idea and certainly might help, but the car does mostly low speed city-type driving where they recommend hotter plugs. The car has Champion RJ8C plugs, which look to be on the hotter side to me. For right now, the Miller Method and the continued use of premium fuel is, I think, the best course of action. I'm also going to wean it off of the octane booster. I agree with packard1984 who wrote that it shouldn't need 108 octane.