Reply To: 8- Cyl Distrubutor Mechanical Advance Question

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I collaborated with Arnold Romberg a couple of years ago on a PASB article (PASB 2007-6) on the advance issue in my Delco 668-E distributor (same as yours). It’s NOT among the PASB issues currently on the website).

The short version is that I found that some previous owner had substituted weight springs, so that my 1930 Model B distributor achieved only 6 degrees of DISTRIBUTOR advance vs the 9 (or 9.5, or 10, different sources) required by published specs. The data published in the PAS Wiring and Tuneup Guide uses ENGINE rpm/advance–18* at 3300 (which is equivalent to 9 degrees at 1650 DISTRIBUTOR rpm. Suggest checking advance at published MAX rpm; advance at lower rpms will take care of itself. Remember that ENGINE degrees and advance have twice the values of DISTRIBUTOR degrees and advance.

The guy who did mine substituted springs from wrecking yard takeouts until he got proper advance. What a difference in performance, and it improved cooling at speed on hot days because the spark was no longer retarded! Be sure to re-bush the distributor if necessary while it’s out.

I know of a 1931 restored Model 41, using the same distributor, that I could tell was very retarded, and the car had cooling and performance issues. I suggested that the advance springs be checked. The existing springs in that distributor were later described as “miniature garage door springs”” that allowed minimal advance! Substituting proper-weight springs greatly enhanced both performance and cooling.

Good luck!