Distributor Tester Findings

[Tom and Amanda Lang <rustnrot@domain.elided>]

Dr. Landry, I.H.,  wrote

>I think you're confusing the section of the repair manual that gives the
>procedures for checking the distributor advance "curve" on a dedicated
testing
>machine... *not* on a vehicle!  Remember that a distributor turns at half the
>engine speed, so 300 distributor rpm would be 600 engine rpm.
>That whole section is informative but not much use if you lack the expensive
>testing equipment.

Somehow I lucked into a "Allen" (manufacturer) distributor tester circa
1950 in excellent condition and working order at an auto swap meet in
Albuquerque, NM a year or so ago for $30, yep, thirty dollars.  Even has a
separate box that has a gauge on it that measures exhaust gases.  Anyway,
I've only played with it one time.  I had several distributors laying
around, mostly I-H.  What I found amazed me.  All the distributor
*mechanical* advances were within 1 degree of spec.  The vacuum advances
were all within a couple of degrees or so if I remember correctly.  Anyway,
the moral of the story, based on my limited sample, is that distributors
stay within spec remarkably.  Soooo, don't assume just because "it's 25
years old" that it *needs* to have the timing curve set.