Vacuum advance spring

JasonNC
JasonNC Expert Adviser
edited November -1 in HUDSON
I have two springs that fit in the vacuum advance. One is stronger than the other and that's the one that I have in the car. Which one is most likely the correct one for a 48 Commodore Six?

Comments

  • Your distributor should be a IAT-4009A, the centrifugal is 9 degrees at 2,000 RPM's. Vacuum advance is 13-3/8" of mercury, no advance, 14" 1 degree, 14-3/4" 2 degrees, 15-3/8" 3 degrees, and at 16" 3.75 degrees. Now both together come out to 12-75 degrees, which is max for that engine by manual, but you can get away with 15 degrees. Use a timing light and this will tell you which spring to use. Walt.
  • JasonNC
    JasonNC Expert Adviser
    The distributor has been changed from the one used in 1948 to 1950 to a 1951 through 54 model. I found this out the hard way when I ordered a new vacuum advance from Dave Kostanek and he sent me the 1AT-4009A vacuum and its arm wouldn't connect to the plate. We're in the process of exchanging vacuum advances. Does that change things, Walt?
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