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Intermittent cutting out...distributor ground wire?


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I'm chasing an intermittent cutout problem on my '53 Special.  When I push down on the accelerator for normal acceleration, it will feel like all power is cut, but it only lasts a second.  It pulls fine at full throttle and has plenty of fuel from the accelerator pump.   In case you're curious, here's what I've checked:

 

1. Fuel pressure at highway speed is 2-4 psi, depending on whether the needle is off the seat or not.  This pressure is after the inline filter.  The gauge is unaffected when the car cuts out.  It pulls fine at full throttle.

2. I've tried three different condensers and two sets of points.  The nut that holds that strap to the points was slightly loose after I swapped condensers the first time, and the problem got way worse.

3. I replaced the point wire to the coil (inside and outside the distributor) several years ago.  

4. Ignition on, engine off, points closed=6.3V at the + side of the coil.  Same at the - side.

5. 3.9-4.0V at the coil with the engine running.

6. Fuel runs out the sight plug just a little with the engine running.  

 

The ground wire from the points plate to the distributor body is original.  It's not great, but it has continuity.  The connector that screws to the distributor body is special so the distributor cap fits on.  Has anyone tried any tricks to make a new wire without this connector?  I can't think of anything...do any of the suppliers sell it?  

If you can chime in here or have any ideas that I might be missing, feel free to add that too.  :)  

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Aaron:

 

I had a similar situation with my ‘53 Special (at least sounds the same from your description) - it was like a slight hesitation under normal load, before the engine “seemed” to kick in. Not quite the same feeling when a car bucks, but a definite lag. 
 

Is that the same sort of condition you’re experiencing? 

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27 minutes ago, Aaron65 said:

I'm chasing an intermittent cutout problem on my '53 Special.  

 

4. Ignition on, engine off, points closed=6.3V at the + side of the coil.  Same at the - side.

 

 

Hi Aaron,

 

I hope there is a mistake somewhere in your description above. When the points are closed this creates the ground to the '-' side of the coil. If you are indeed reading 6.3 volts on both sides as stated you have an open circuit between the '-' terminal of the coil and ground through the points. Now if the points are actually open, your readings are correct.  With the points closed you should read 6.3 on the + coil terminal to ground and basically 0 on the - coil terminal. Let us know and we will try to help 😁.

Edited by 37_Roadmaster_C
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EDIT:

 

First, thanks Robin.  I did a ton of investigation over the last day or two after work, and I may have crossed wires in my head.  Either way, I figured it out.  My newer wire from the points to the coil broke at the connector.  When the vacuum advance moved the points plate, it broke the connection momentarily.

 

New questions:
1. Modern wire insulation seems less flexible than the original, and I think that caused the wire to bend at the connection rather than bending the wire.  I made my new wire a little longer to offer more flex.  Is there an alternative with more flexible insulation?  I used 16 gauge wire.

2. My ground connector question still stands.  I'd like to fix that at some point soon.

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Aaron, the flexible wire used inside the distributor is available. I can't remember where, but have seen it recently.  Perhaps one of the wiring harness companies?

 

 I went to electronic ignition and have not looked back.  The pertronix is a good, inexpensive and reliable system. It CAN be a problem for six volt systems if the voltage is not up to snuff.  As can other things.

 

  Ben

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5 hours ago, Ben Bruce aka First Born said:

Aaron, the flexible wire used inside the distributor is available. I can't remember where, but have seen it recently.  Perhaps one of the wiring harness companies?

 

 I went to electronic ignition and have not looked back.  The pertronix is a good, inexpensive and reliable system. It CAN be a problem for six volt systems if the voltage is not up to snuff.  As can other things.

 

  Ben

I've switched to electronic in 5 out of the 7 as well...new points just seemed to be a crap shoot.  The only thing keeping me from making the switch (ha!) on the '53 is the generator; I've read that electronic modules don't like the inconsistent voltage.  I forget...did you convert to 12 V?

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46 minutes ago, Aaron65 said:

I've switched to electronic in 5 out of the 7 as well...new points just seemed to be a crap shoot.  The only thing keeping me from making the switch (ha!) on the '53 is the generator; I've read that electronic modules don't like the inconsistent voltage.  I forget...did you convert to 12 V?

 

 I did. Happy with that as well. And the Fuel Injection.

 

 Six volt alternators are available.

 

  Ben.

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