why is there a small hole drilled into the body of my Autolite IGS-1107s Dist Cap?

[desoto1939]

The next time you are at a swap meet and pickup a NOS Distributor cap examine the cap very closely. 

 

 You might find a very small hole about 1/16 inch drilled into the side of the cap.

 

You might ask yourself why is there a hole in the cap and other caps do not have this hole.

 

The Chrysler cars and trucks were known for getting moisture in the caps especially with the butterfly style hoods.

 

Some Chryslers, and a few other makes, seem to have a problem with moisture collecting inside of the distributor cap.

 

One solution was to drill a 1/16 inch hole on the back side of the cap. In fact, some of the early day distributor manufacturers put 

 

the hole in the cap when they were being manufactured.

 

In later years this hole has seemed to disappear.

 

My Autolite  IGC-1107S caps  have the hole drilled into the cap.  

 

Autolite supplied most of the electrical parts for the MoPar cars and trucks.

 

So go and look at one of you spare caps to see if you have the hole.

 

If your car is developing a hard starting issue in cold and wet weather there might be moisture inside the cap.

 

I know some people spray the inside of the cap with WD40 and then wipe the inside of the cap and make sure it is dry and then put 

 

the cap back on the dizzy and the car/truck fires right up.

 

On the pictures attached is an Autolite and a Preferred cap for my 39 Desoto and note that both have the holes in the cap and the instruction for the plug. 

 

Tech Tip

 

Rich Hartung

Desoto1939@aol.com

 

Edited February 6 by desoto1939
added pictures

[JerseyHarold]

Good info.  I've heard the hole is an ozone vent for ozone that is created by the ignition points sparking when they open.

[Sniper]

You know, I haven't had a match since Superman died.