Distributor Vacuum Advance

[WarEagle]

Does anyone know how much vacuum it should take to move the vac advance for timing? The spring that is in now seems very stiff. With the spring removed, the diaphragm moves easily. With the spring in, almost no movement. Its a new motor and is not running properly yet so I'm thinking this may be part of the issue..

Also, how far should the vacuum advance move with vacuum applied? 1/4 inch or so max?

Thanks

[colnago]

I don't have a direct answer for you, but I remember that I was able to see my vacuum advance move when I hooked up a Mity-Vac to the line, and started pumping. Depending on the distro, you should be able to get spring kits for it. Can you adjust the vacuum "can" on the distro by turning a screw on the inside with a tiny screwdriver or hex key? Some have it; some don't.

Joseph

[MTM]

I am not sure about the vacuum canisters for 300 6 engines, but I do know that for the FE family there were many different options for total advance. Some were 20 deg and some as little as 7. I have read about adjustable ones but not used one. Since the 300 is only a truck/van engine I would think that they would have less variation.

Keep in mind that it is probably hooked to ported or timed vacuum, which means that it won't move until off idle. As mentioned above, try to get a mighty vac on it and see what it takes to move it. If you have a timing light you can see how many degrees that it is capable of moving it and at how much vac. You could also rig the mighty vac up as a gauge while you drive to see your vac signal and get an idea of how much advance it is giving you.

[MadMike]

Dunno about the 300, but for the 240ci car.
Dist # D2AF-BA
0° @ 5inHg
6.5-9.5° @ 20 inHg.