Dinking Around Inside My Distributor

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So this weekend I start my 'A'. She fires right up. First try. Runs for about 12 to 15 minutes in the garage. I'm looking at the coolant, check the coolant level with my stick and just watching and listening to her run. All sounds normal.

I back her out and head down my street. A half a block later I stop at the stop sign and diddle across the road and shift slowly into second. It's like the ignition was turned off. She dies and I coast over to the curb on a deserted road. No detectable spark. I walk home and tow her home with the tow strap.

Fuel flows freely out of settling bowl, and strainer screwed into carburetor. I don't think the float is stuck or sank in my gasaholed B.P. fuel.

Back in the garage I go through the 6 volt test.
Ignition 'OFF'.
6 volts at the battery,
starter lug,
ammeter terminal bax wing nuts [+ and -],
both sides of the coil, alt.
~and horn, parking, low and high beams and brake lights all work.

I have a stock lower plate that is electrically isolated and the wire is not shorting out going to points. It ran on both new and old condenser and coil. Switched back to old coil.
I have the modified modern point upper plate with pristine set of 1970 Ford V-8 points and condenser.

Ignition 'ON'.
Suddenly no detectable 6 volt or spark at the points or out the coil high tension wire when I open and close the points by hand.

I pulled the distributor, took it apart. Clean as a whistle. It has a two piece drive shaft. No play in the works. Marking on the outside of distributor body has SP stamped on it. And inside is stamped 61 31 10

So I'm looking with jaundiced eye at that early style 1928 to mid 1930 ignition cable with that ignition wire shorting out inside the armored cable from the terminal box to the distributor body. I'll be checking to see if the screwed in part to the distributor is screwed in too far and shorting out at the plunger contact area or the lower isolated plate, therefore un isolating the lower plate.

I have a aftermarket replacement type ignition cable [non-pop out switch] using a small 3/16" cable with a screw in connector to the distributor.

Q. This ignition wire is hot with the key 'ON' right? This cable touches the 'detent' of the lower plate right? If it looses contact with the lower plate, it's like turning off the key right? What energizes this conductor [cable]? Just by turning on the key switch? Does the detent on the lower plate move when the distributor is advanced or retarded? Then the tip of the cable would have to move with the plate right?

Any ideas? Maybe I should just hot wire the thing. Thanx. skip.

[Geo. H]

Look at your wiring diagram, think about it. power goes to the coil, out the other side and then to the points. What completes the circuit? The ignition switch! If you lose power at the coil when you turn on the ignition switch, it's probably because the points are closed, and the whole circuit is grounded.

[lindy williams]

If you have a repro terminal box, make sure the studs are tight in the box and not shorting out intermittently against the firewall. Happened to me.

[Tom Wesenberg]

6 volts on both sides of coil means the current isn't getting through the points to ground. No 6 volts at the points movable contact when open means the current isn't getting that far and the most likely stopping point is the switch. Try shorting the points contacts with a screwdriver, just because it's a quick easy check and may show dirty contacts. When I worked at the GM dealership we had a few points that wouldn't conduct across the contacts right out of the foil sealed box.

I think however you may find the problem to be a switch that isn't making contact across the brass parts inside. Some of these repro switches are real junk and don't make a firm click with good contact across the brass contacts inside. Just use a jumper wire across the 2 switch contacts to see if you now have current to the points.

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OK she starts right up. I did NOT run the ignition cable through the armored cable since I don't run a pop out key switch. That armored cable appeared to be too long anyway and really bent over the ignition cable up under the instrument panel. So it's out.

Dist is fitted with a modern upper plate with condenser so the lower isolated plate really has nothing to do but provide a landing area for the spring loaded ignition cable's end with it's screwed in connector. Which is not grounding out by being screwed in too far. The isolated connector is separate from the armored cable. They are two pieces.

Key switch repeatedly tested good. Points make and break. Coil makes a strong spark, at least 5/8" and I really did a careful point setting of 0.20 and set the point block right where I wanted it to make that distinctive retarded lope. BTW, the coil post marked 'DIST' goes to the red wire on the passenger's side.

When the distributor was out of the car with the continuity meter hooked up between ground and the points I spun up the shaft to open and close the points and the meter would beep indicating nothing was going to ground when the points opened.


So the only thing I did was to R&R the condenser. I'll have to test drive and see if we have a failure again. If so I'd suspect the coil.

Thank everybody for all the suggestions.

skip.