Distributor Vacuum Advance Issue

[EW1BH27]

While a friend and I were carb adjusting to make my car idle nice he found that the distributor's plate wouldn't budge until 17.5 in/Hg of vacuum. When the distributor was rebuilt and tested advance would start at 7 in/Hg. The vacuum module/diaphragm is fine, holds vacuum no bleeding. The tool he was using is similar to the pictured one. The distributor is a Mopar electronic one.

That's the issue, why does it now take so much more vacuum to get the advance (plate) to start moving? Do those plates eventually bind through time? TIA, John

 

[Xcudame]

Hopefully Halifaxhop will chime in as he rebuilds distributors. I do know the distributors need to be oiled. there's a piece of felt(?) in the center of the shaft under the rotor that needs a few drops every so often. I doubt many people oil their distributors.

 

[Steve340]

It sounds like the points/ignition trigger plate is a bit seized. With the vacuum unit removed the secondary plate should move freely.
They also need to be lubricated.

 

[halifaxhop]

Almost sounds like it is not adjusted right. Turn the screw in to make it come in faster.

 

[cuda joe]

nice cutaway pic halifaxhop thanks for sharing

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