Getting it narrowed down, finally!

Terry NJ

Terry NJ

Well-known member
I took the coupe (Green wheels) out shopping this AM. True to form, it started beautifully when cold, but wouldn't fire when hot. Here I was in the parking lot with a model A that won't start. I even briefly considered sitting there till it was cold again. Actually it was a great time to try to figure out what's wrong with it. I didn't have a meter or a test light, but I did have a clip lead. I chased the current downstream to the points. NADA!She's timed pretty well and I didn't want to disturb it. I got a flash of genius! Suppose I rotate the plate first right then left and it will reposition the wire under the plate. I did and it did. It fired right up. So I wasn't going there because I had "rebuilt" the distributor last year and had been very particular about that wire as it's a known trouble maker. I still have No idea how that particular part is Not functioning perfectly. I thought you might like to know.
Terry
 
Hi Terry,

Every time we do something with a Model A and we think it is 100% perfect and we refuse to check it twice ..... it is obvious that we are not following the advice of one of life's most important parables in our youth ........ "He's making a list and checking it twice!"
 
This is something that happened to me ... I did not read it somewhere!! :D

On the DRIVER's side of distributor there is a hole where Condenser screw is located.

Look inside the hole at the strap that the condenser mounts to the lower plate. (at the three o'clock position inside the hole) ...

Sometimes these lower plate straps are not formed (bent) correctly and the strap will short on the edge of the casting.

Sometimes they only short out when engine is hot.

Eventually the paint will wear off the casting and short will be "solid" all the time.
 
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Mr. Benson is on the right track ...... we can all imagine that a spark lever is not a Good Witch's Magic Wand that one waves to start a Model A .... just take the time to investigate and carefully observe "everything" that can move to see exactly what this spark lever is moving.
 
H. L. Chauvin said:
Hi Terry,

Every time we do something with a Model A and we think it is 100% perfect and we refuse to check it twice ..... it is obvious that we are not following the advice of one of life's most important parables in our youth ........ "He's making a list and checking it twice!"
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What about the parable that says, if it ain't broke, don't fix it. . . :)
 
I once saw an over restored distributer give grounding troubles.He had painted the housing with some good paint,then lube the hole in the center of the plate and also the three ears on the plate.I felt that with the three ears on the plate rubbing,the hole in the center rubbing,the spring underneath rubbing,and the spark rod connected,it would have to ground somewhere.The car would quit and if you wiggled the point plate it would start right up again.We were all kind of looking at the lower plate wire,but it turned out to be the good job he did on restoring the distributer.The guy that figured it out knew nothing about A's,but he did know old cars and pinpointed the problem in a few minutes.
 
Hi 29,

Could be incorrect, but appears parable distinctly refers to "if it ain't broke" .... difference appears to be ..... his is "still broke" after "fixing it" ..... e.g., back to the #2 Santa Clause parable.
 
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Keith, I've noticed that among all distributors I own, not one came from the factory with painted innards. Putting paint on electrical parts would make me nervous just for the reasons you give.
Terry


Keith True said:
I once saw an over restored distributer give grounding troubles.He had painted the housing with some good paint,then lube the hole in the center of the plate and also the three ears on the plate.I felt that with the three ears on the plate rubbing,the hole in the center rubbing,the spring underneath rubbing,and the spark rod connected,it would have to ground somewhere.The car would quit and if you wiggled the point plate it would start right up again.We were all kind of looking at the lower plate wire,but it turned out to be the good job he did on restoring the distributer.The guy that figured it out knew nothing about A's,but he did know old cars and pinpointed the problem in a few minutes.
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Hey! I want to get everyone's opinion of this mod. It seems like a terrible oversight on Henry's part that the dist. plate will not lift over the the dist. cam. I've got the timing pretty good and I don't want to disturb it, but I want to see under the plate. Hows about if I were to enlarge the hole so it can go over the cam? What could go wrong? The spring?
Terry
 
Terry said:
Hey! I want to get everyone's opinion of this mod. It seems like a terrible oversight on Henry's part that the dist. plate will not lift over the the dist. cam. I've got the timing pretty good and I don't want to disturb it, but I want to see under the plate. Hows about if I were to enlarge the hole so it can go over the cam? What could go wrong? The spring?
Terry
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Enlarging the hole will destroy the index of the upper plate and points to the dist body casting and as such if hole is enlarged, the point gap will vary all over the place when you operate the spark lever...

The upper plate indexes to the casting at that point.
 
Hi Terry,

I greatly admire your tenacity and willingness not to give up.

Most who have owned Model A's for a few years can appreciate having experienced intermittent difficult conditions to sometimes cause us to wonder why all of sudden our Model A's refused to start ..... and later started for no "apparent" reason.

Because of after reporting moving your spark handle up and down resulted in allowing it to start, in looking back at your first post above, if it were mine, I would at least give these a try:

1. Attach a testing device to test "continuity" on everything that should be grounded in or on your distributor, (even verifying a perhaps loose, moving, upper distributor plate); then move your spark handle very slowly up and down several times to see if you maintain said grounded "continuity" everywhere; and subsequently,

2. Attach a testing device to test "continuity" on everything that should "NOT" be grounded in or on your distributor; then move your spark handle very slowly up and down several times to see if you maintain said non-grounded "continuity".
 
as long as the rotor goes back on in the same position your timing won't change.when I took my upper plate off I set the rotor to 12 o'clock and put back in the same position the timing won't change if you don't rotate anything.
 
chl said:
as long as the rotor goes back on in the same position your timing won't change.when I took my upper plate off I set the rotor to 12 o'clock and put back in the same position the timing won't change if you don't rotate anything.
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Technically your right but practically very had to do and get it exact.
 
Set the rotor to the edge of the cap contact, as in this picture, and it will be easy to reinstall the cam the same way. Just be sure all the freeplay is before the cam rotation. In other words give the rotor a light twist clockwise when you line it up like in the picture.
 

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Hi, Terry,

It appears this simple to me ... from your Initial Post No. 1:

The "visible" mechanical movement of your "visible" mechanical spark handle appears to be mechanically moving a "visible" mechanical item in your distributor ...... which in turn ...... this "visible" mechanical item appears to be causing an interruption of a totally "invisible" (+) and/or (-) electrical current ..... which in turn ...... is trying to provide a spark at the (+) and (-) contacts at your spark plug gap.

As described in reply # 11 above, using an electrical testing device is one way to try to monitor the transmission or interruption of this "invisible" much needed electrical (+) or (-) current.
 
It balances the rotor, so it takes the side load off the bushings, except for the pressure from the points arm. It will also result in more even firing if the bushings have any play.
 
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