distributor issue on my 39 Desoto

[desoto1939]

If have an Autolite IGS4102-c original dist in my 39 Desoto. I pull the dist and replaced the breaker plate with a NOS unit.

 

Set up the points to a 20 gap with a snap gap tool.

Then when testing the gap at each point on the dist cam I am noticing that on some points on the cam the points are not opening or are smaller than the 20 gap.

 

Has anyone else had an issue like this.

 

The dist shaft is nice and tight no slop, no slop in the breaker plate.  Could i have a worn spot on the cam.

 

Since most 6 cylinder Mopar car/trucks used the Autolite dist would anybody know if another cam from a later autolite dist would work as a replacement cam?

 

My Autolite catalogs do not list this part so i can not do any cross checking.

 

Any and all help appreciated.  

 

I have put out swome fellers to several of the major Mopar parts venders.

 

Thanks,

Rich Hartung

desoto1939@aol.com

[Jerry Roberts]

Rich ,  The Auto Lite part number for your distributor shaft is IGS-1081RB . That shaft also fits the Canadian Dodge D11 . D12 D13 . Also fits 1938 Dodge truck RC (T158)and RD(T60) I could look further if it would help . 

Edited December 7 by Jerry Roberts

[Sniper]

You could take a set of dial calipers and measure across the points on the cam lobes to see if you're getting a variance in width. That would confirm the cam is your issue because it would surely suck if you went through all the aggravation of finding a new one and it wasn't your issue. I suppose you can measure across the flats too cuz your variance could possibly be there as well. Doubtful but hey it doesn't take much to check them.

[kencombs]

How much difference in the point gap can you measure?   I wouldn't be surprised to find a new one having 'some' variance but a few thousandths won't materially effect the running.   For instance, You could set the gap at .018 or .022 and probably never be able to feel the change.   So one lobe a thou or 2 low wouldn't hurt much and may have even been that way when new.   On the other hand, maybe no one ever used that little lube tube that came with new points back in the day.

[Ivan_B]

I would check for run-out on the highs of the cam. If the points are not opening, that probably indicates that either the rotor is wobbly or something else is messed-up 🤨

Edited December 8 by Ivan_B