short in distributor keeps reappearing - any ideas?
 

Hi there - long story short (pun not intended) - got stuck by the side of the road, traced it to a short somewhere in the distributor.

Using Les Andrews' 4-3 Troubleshooting chart, at step 5 "Turn ON ignition switch and test for 6 volts on the open point arm", the needle on the multimeter barely moved. Easy, I thought - a short somewhere inside the distributor. Taking it apart didn't show any obvious problem, so I put it all back together (and used an emery board to rough up the armored cable plunger, the indent on the tab where the armored cable makes contact, the tab where the condenser screws into, and the condenser where it makes contact with the tab).

Checking again showed 6 volts at Les Andrews' step 5. Homefree! (or so I thought). Turning the engine over still wouldn't start - and going through the troubleshooting again showed no voltage at step 5 ("Turn ON ignition switch and test for 6 volts on the open point arm").

Ughh - so, it looks like I have a magic reappearing short in the distributor - any ideas what to look for?

Thanks in advance!

Re: short in distributor keeps reappearing - any ideas?
 

I had a similar problem, If your using a fuse on the top of the starter that assembly can get corroded and connections at the rivets can get loose. Second if you have over oiled your distributor I've been told it can cause problems from the overflows, Third if it is a modern points, upper and lower plate other members have experienced problems leading back to a ground or loose connection between the wire or the tab on the plate. Keep us posted what you were able to find out

Re: short in distributor keeps reappearing - any ideas?
 

the tab on the lower plate could be touching the distributor housing due to popout cable being screwed in too far or a repro lower plate could be shorting between the tab and the lower plate or the wire between the upper and lower plates could be shorting to the distributor housing.

Re: short in distributor keeps reappearing - any ideas?
 

You could have an intermittent short in the distibutor or the pop-out cable. A way to isolate as to which one is to make up an emergency by-pass cable (it is a good idea to carry one with you). It is made from the end of a discarded pop-out cable. You need just the part that screws into the distributor. Attach a wire with a clip lead to it. Remove the pop-out cable from the distributor and screw in the by pass . Remove the red wire from the distributor primary connection and attach the clip lead there. If there is no short in the distributor the car should start and you can drive it that way for a few days to make sure the intermittent has gone away. You will have to remove the clip lead to shut the engine off.

If the problem persists the intermittent is in the distributor. Take it apart and find what is shorting. More than likely the lower wire connecting the two plates together.

One of the few things I always carry with me is a rebuilt road tested distributor and a by-pass cable. I have used it more on other people's car than my own.

A shorted pop cable can be repaired. I would send it to Cal Allen the "key guy". He specializes in them.


Tom Endy

Re: short in distributor keeps reappearing - any ideas?
 

If you are running orignal type points, check to make sure that the copper strap that follows the flat spring is not too long and shorting to the case. I had this problem and it was not easy to find, simple to fix, just put a bend in it to use up the slack.

Re: short in distributor keeps reappearing - any ideas?
 

Screw the ignition cable only in far enough to make contact with the lower plate. Bob

Re: short in distributor keeps reappearing - any ideas?
 

knowing what kind of setup your running helps
original, modern, pop out , etc

Re: short in distributor keeps reappearing - any ideas?
 

If you are using the stock setup, check your ammeter. It acts as a fuse and can cause lots of problems if it is marginal. Next time it happens, wrap a small wire around the nuts that hold the junction box cover on and try to start the car. If it starts, the problem is not in the distributor.

Re: short in distributor keeps reappearing - any ideas?
 

Oh, yeah, forgot to mention - original setup, except that the popout switch has been replaced with a modern style (simple turning switch with two connectors on the back - much like this:
https://lh4.googleusercontent.com/-W...tionSwitch.jpg

Thanks for the tips so far - I've got quite a few things to look into now...

Re: short in distributor keeps reappearing - any ideas?
 

I've had problems with the modern switch before can jiggle so just turned off. To all the world looks like is still on but isn't . Also can short out if and when the terminals touch the gas tank . Karl

Re: short in distributor keeps reappearing - any ideas?
 

Karl beat me to it. I was going to list those same two faults as soon as I saw the picture of the repro switch.:eek:

Re: short in distributor keeps reappearing - any ideas?
 

I had same problem with terminals touching the gas tank.

Re: short in distributor keeps reappearing - any ideas?
 

Those cheap ign switches are junk.I use the modern switch that is modified to look like a pop-out but doesnt "pop".They are a good quality switch.I always stick a few layers of tape on the tank behind the switch.

Re: short in distributor keeps reappearing - any ideas?
 

A poster that had no current to his points once mentioned that the rivet on the incoming end of the pigtail wire seemed tight & no corrosion. He took it out & set the rivet tighter & VOILLE' he had current!
On a similar theme, I've seen loss of current in junction box studs, even though they're tight & no visible signs of corrosion. Just tighten them tight & add internal/external star washers. Somebody once posted, "STAR WASHERS ARE A GROUND'S BEST FRIEND"!! The Dog:cool: is my Best Friend & helps me recomember all this crap! Bill W.

Re: short in distributor keeps reappearing - any ideas?
 

Quick update - now that it's the weekend again, I had some time to troubleshoot this some more.

Started out as it was left - no voltage on the points arm, so I checked to make sure there was 6V on the armored cable plunger (there was), then proceeded to take the distributor apart again and checked for electrical continuity (and shorting) along the entire path from the tab on the lower plate that the armored cable plunger contacts, through the pigtail, to the points arm and everything seemed fine (continuity wise).

Putting it all back together, not so fine - again no voltage on the points arm.

Removed and reinstalled the condenser, and suddenly had 6V on the points arm. Trying to start the engine doesn't work, and afterwards the 6V at the points arm disappeared.

Long story short (again, no pun intended) - it appears that when the condenser is installed, a short (sometimes) magically appears, and definitely appears after trying to start the engine. (I've now checked this two more times). Visually examining the lower plate tab that the condenser screws into, it definitely is not touching/shorting out to the distributor body.

So - help! Is it possible that the condenser itself is bad and needs to be replaced? It's pretty much brand new, with less than ~200 miles on it. I checked for continuity between the condenser body and the contact on the end, and there doesn't appear to be any - but the short appears AFTER turning the engine over - maybe it needs to be in a charged state to have the short appear? I don't really know - just guessing now from what I've observed. Any new ideas on what could be the problem, given this new information?

Thanks in advance (again)

Re: short in distributor keeps reappearing - any ideas?
 

It's called "infant mortality" - when things break down early in their lifespan.

New condenser time. I think you can buy these at Ford still? Probably at NAPA.

I haven't done this recently but one used to be able to get "routine" small buck parts from local sources.

Although come to mention it, I haven't seen the tt10 spark plugs at AutoZone recently (although I bet they can order and have it at the store the next day.)

Yup. Napa has them http://www.napaonline.com/Catalog/Ca...FA5_0182283939

$9.99 Check your local for off the shelf.

NAPA has at least 5 pages of Model A specific stuff.

Joe K

Re: short in distributor keeps reappearing - any ideas?
 

Again, did you check this situation out. The problem I had with a switch like this is that it took some time to rub the paint off the gas tank before it started to short. The way I found I had a short, and I think Tom mentioned to check this, is I found the coil was warm.

Another thing you could do would be to replace your distributor with a known good one (if you can find one) and see if that makes things better. Another thing to check may be your points-are they in good shape.

Re: short in distributor keeps reappearing - any ideas?
 

Buy a condenser from A&L, sometimes listed as "burn out proof" in other catalogues, I havn't been able to cook it in 20+ years.

Re: short in distributor keeps reappearing - any ideas?
 

Yeah - checked that - the contacts on the switch are well-wrapped with electrical tape to preclude any shorting there; also had a bybass cable on hand (as recommended by Tom Endy - thanks, I hadn't thought of that) to isolate things a bit - still the same results - I can get the short to disappear briefly (dismantling the distributor and putting it back together), but as soon as I turn the engine over, it reappears, then removing the condenser makes it disappear.

I think my next step may be to get another condenser. A bit disheartening - the thing's only been in use for maybe a few months at most...

Re: short in distributor keeps reappearing - any ideas?
 

The NAPA condenser in post #16 says 36 month/36,000 mile guarantee. FWIW
Paul in CT

Re: short in distributor keeps reappearing - any ideas?
 

Two important things to look for in the distributor are the insulating washer that goes under the condenser screw head, and the bottom plate wire terminal. The insulating washer not only keeps the buss bar on the lower plate from hitting the cast body, it keeps the screw from bottoming out in the end of the condenser, which can lead to the condenser terminal spinning and ruining a good condenser. The flag terminal MUST be bent at 90* (as Marco has pictured in the past) so it hugs the hex nut on the points pivot stud. If it isn't bent down at 90*, it can reach the spring and short out.

I better add one more thing to check is that the points spring and thin copper strap must not touch the distributor cam at any time, or it causes problems.

Just to be sure, when you check for voltage at the points, you DO HAVE THEM OPEN, don't you? If the points are closed, then you are sending the ground path to the coil, and will have no voltage reading.

Re: short in distributor keeps reappearing - any ideas?
 

Not sure if anyone mentioned this already but the lower plate in mine has a metal thing riveted to it that the condenser is screwed to and the armor cable makes contact with. Mine appears to have decaying insulation where the rivets are. Could be worth checking if you think it is shorting there.

Re: short in distributor keeps reappearing - any ideas?
 

Re: short in distributor keeps reappearing - any ideas?
 

Another update -
I remembered that I had my old condenser (with a broken off tab) still laying around; I figured duct-taping the tab on would be enough to have a connection to test things out.

Success - sort of. I successfully got voltage back to the points arm (yes Tom, I made sure to keep the points open with a piece of paper when checking - I have forgotten to do that before in the past, though, so thanks for the reminder).

But - still no go on starting the engine. So, I tried pulling the coil wire and holding it near a stud on the engine block and manually pushed in the starter button - yes, there's spark.

I guess maybe I should have loosened a brass strip and actually witness spark going to a spark plug; I'll try that tomorrow, it's getting kinda late & my brain's frazzled (and a bit frustrated).

At least I know that the "new" condenser (that had less than 200 miles on it) is probably bad. Maybe the duct-taped old condenser is good enough to generate spark, but not good enough to get the engine started? I guess I'll find out once I buy another condenser - thanks Joe K for the NAPA tip - there's plenty of them around; I'll try calling them and see if I can get one in short order.

Thanks for all the tips - I feel like I've been going over the innards of my distributor with a fine-toothed comb over and over again now...it was kinda fun at first, but now is just a bit frustrating...

Re: short in distributor keeps reappearing - any ideas?
 

You can solder the ground strap to the condenser body.

If you've never experienced it before, a shorted rotor can leave you scratching your head for a while. The first time I saw this was in the 70's when I was tuning up a customer's newer Ford. The coil had good spark, but then engine wouldn't fire at all. I finally traced it to a rotor sending the spark from the flex contact, through the plastic, and to the steel shaft.

Re: short in distributor keeps reappearing - any ideas?
 

Another thing to check may be your points-are they in good shape?

Just a thought again.

Re: short in distributor keeps reappearing - any ideas?
 

Would you happen to have a different lower plate that you can swap out for a test run?. When the plate goes bad the tab on the bottom will show continuity to the main part of the plate. The insulating washers that the rivits pass thru may be old or on the intermitant part of being good/bad.When pressure from the ingnition cable or even reassembly into the distributor body or vibration from engine running might possibily cause the the plate to go to ground. This condition may only happen possibly when you've gotten everything togather. This could disapear when you remove part of the assembly or move it to the bench for inspection and testing. You would not be able to determine by a visual check of the rivits or washers if this odd thing were happening. A long shot but one more thing to consider.

Re: short in distributor keeps reappearing - any ideas?
 

All kinds of ideas listed so far, and all good ones to!. So to add some "out of the normal" problems I have seen on coil type ing. issues. One thing to try, is watch the coil, and dist in the dark, you maybe surprised to see sparks at places you never thought. I have found both coil and dist cover problems this way. The smallest carbon path in the wrong place can cause all kinds of problems. I posted it before but now I found a picture to add, take a good look at the copper strap on the points, I am here to tell you I spent hours working on a dist "shorting out" problem, no matter what I did it would start to work and then fail, it was all caused by the point strap that would touch the case whenever it felt like for just as long as it felt like. It about drove me crazy (maybe a short trip to crazy anyway!).

Attachment 121634

Re: short in distributor keeps reappearing - any ideas?
 

Here's the link to the Napa condenser.

Was really surprised to see all the Model A parts that Napa has, especially the original style Champion spark plugs for less than the Model A houses sell them! Here's the link.

Some other distributor parts from Napa:

Points
Rotor
Oil pan gaskets
Head gasket
Intake/exhaust manifold gasket
Full engine gasket set
6 volt ignition coil
Ignition coil mounting bracket
Fan belt
King pins
Generator brushes
The list goes on....

Re: short in distributor keeps reappearing - any ideas?
 

There's still some Model A stuff out there in the real world.

Too bad not Midas Muffler. I have one of those on my truck still.

Do you think the warranty is still in effect?

https://www.youtube.com/watch?v=mFOWdIPQImk

I loved the commercial. Trouble is I find as the years pass I more and more resemble John Hoyt. Well, maybe Jack Benny.

Joe K

Re: short in distributor keeps reappearing - any ideas?
 

I am thinking that I have a short also and appreciate any help. I am not a mechanic as you can tell.

1. About 3 yrs ago, replaced all parts inside distributor, coil, points, lower and upper plate with new black wire, all new wiring harness, stem to crank. Car ran nicely for short period of time.

2. In that same timeframe when we had it running, I tried to start it and would not start. Traced it to no spark. Changed coil again. Still no spark.

3. Traced lack of lack of connectivity to a 90 yr old ignition switch. Replaced it last week with new one from MacÂ’s.

4. Replaced old style (lower unit) condenser with new.

5. Car started for only 3-5 seconds - ran rough so I tried to advance points manually on column and engine quit. This has happened 2 times in about 30 attempts to start. Again no spark. Seems like it might initially have spark and then it goes away (why I think a short).

6. Noticed that Mac’s sells point terminal mounting kit with insulating washer so I ordered that. Also noticed in thread that condenser screw should have insulated washer. My condenser has 2 screws, one to hold it in place and other screws to ground lower plate. Which one gets the insulated washer?

7. Any other advice would be great.

God Bless

Re: short in distributor keeps reappearing - any ideas?
 

The dist. plate needs a good ground. I've had such a problem and moving the advance/retard lever while driving was a temporary solution.