Distributor body inside contacts question

The Geezer

The Geezer

Senior Member
My distributor body is out-of-round. Can the inside contacts be built up with regular or silver solder? Is there another way to build them up to get an even gap?
 
are you talking about the black Bakelite lower cap that the plug leads connect to?
if so my opinion is to buy a new one.
or
is there a special reason why you want to save it?
 
You can bend the contact point on your rotor upwards to close the gap(s).
Any that are too close you can file the contact point(s) on the distributor body to open them up to the correct gap.
 
There are little sparks that jump from the rotor to the contacts inside the housing. That may create enough heat to melt solder or even silver solder.

Update: The spark is not enough to melt solder, depending on where you put it, see posts #10 and #11.

First, make sure that the distributor body fits snug on the distributor. If it does not then it can move and change the gap at the different contacts. Besides buying a new body, you could try filing down the closer contacts and then bending the rotor as crosscut talked about, above.

I found that my car runs better with a small gap between the contacts and the rotor. I think the specification is 0.025 inch, but I run about half that amount. The trick is to have the minimum gap without crashing the rotor with the contacts.
 
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These slides may help you. Before discarding the out-of-round cap, put it into boiling water for a few minutes, then let it cool in the air. This may relieve internal stresses in the plastic making it go round. If not, get a new cap.
 

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The clear "caps" that are sold are fun - and can be left in place as a "show & tell." But a better diagnostic tool is to take a standard plastic "opaque" top and cut two moon shaped slices one off of each side leaving a center connection "bridge" held by the two clips. You can see the rotor passing by the four terminals VERY easily with this.

The modified top cap tends to collect water in the rain. Ask me how I know.

Joe K
 
Is this really that much of a concern? As long as the rotor does not hit the contacts? You can't even measure that gap on newer cars. How would you measure it if you were using a modern cap on a Model A distributor? Well, I suppose you could but not easily.

I certainly wouldn't lose sleep over it.
 
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Having just went thru two distributor rebuilds...somehow I've ended up with a half dozen new rotor caps and two new bodies. The gap with the new rotors and the new bodies is horrific...nearly 0.05". Some of the new rotors could not be bent enough to get the gap less than 0.04" (and still be level with the body contacts). I finally found an old cap (steel rather than brass) that I could bend enough to get an acceptable gap (0.025"). The original was loose on the shaft and had 0.032" gap average (I kept it anyway).

The original body I got with the car has the closest gap with the longest cap in the collection. The new bodies were way too big for anything but the old steel cap I found.

I don't think there's enough heat energy in the spark at that point to melt silver solder...but it certainly wouldn't hurt to try. All it would cost is a new dist body.

Mind the gap!
 
Years ago, I had a distributor that had way too wider gaps. I decided trying to bend the rotor arm was too risky for fear of breaking it so I soldered a small off cut of brass shim to the top of the rotor and filed it till I had a nice small gap. I used ordinary lead/tin solder and it was fine because it is away from the actual spark.
 
I did some rough calculations and the amount of power at the spark between the contact and the rotor is about 3 Watts. The breakdown voltage is about 2,000 and the current is about 0.0015 amp. W=IV so about 3 Watts. The time is very short so the energy is very small and is carried away by the metal. But there are many sparks over a second in a running engine. As Arnold found out, the amount of energy is not enough to melt any solder, at least were he put it. I still would not put any solder on the contacts.
 
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Thanks to everyone for your help! I will be trying both Synchro and Bob Bidondes's suggestions just to see what I end up with. There is only one contact on the body that is way out, so I might put a drop of silver solder on it and file down to match the others.
This was a NEW distributor body!. I have already ordered another in hopes (I'm not holding my breath) it is not screwed up too. Thanks again all.
 
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