questions about ignition - 36 plymouth so sorry slightly off topic

[n1gzd_plymouth]

I also posted this on a more appropriate forum but this group is such a good resource that I decided to post it here too.

I am replacing all of the ignition parts on my 36 coupe. It appears that my ignition coil could be orignial so I want to replace it so that I can eliminate a possible weak coil from some problems that I was having earlier (just want to start out with new ignition parts). I have what appears to be the original type coil that is mounted stuck into the firewall (and it might be the orignal one - it looks old).

Bear with me, this is the first time I have encountered this type of firewall mounted ignition coil.

http://www.pangalacticconsortium.com/cars/PlymouthGallery/imgpages/image019.html

The coil ignition cable has a threaded connector on it (screws on, not plug). One coil power site is on the side of the coil in the engine area (forget if it is hot or ground). Inside the car under the panel there is what looks like conduit coming from the back of the coil and it runs to the ignition switch. I can only assume that this is the other side of the power to the coil that is switched through the ignition switch.

Why did they do this, was it a security measure (hard to hot wire the car)?

Anyway,here are some questions:

I am guessing that there is a way to separate the coil from the firewall bracket and the metal conduit on the back. It was not obvious when I looked at it how it could disconnect and I did not want to break it.

I pointed a flashlight on the back of the coil and all I saw was the conduit but in a catalog pic (andy bernbaum) I saw what looked like a connection for the other wire. Is there actually supposed to be two things on the back, ignition lock conduit and power wire?

The firewall mounted coil in both catalogs that I looked at is very expensive ($129.50 vs $39.50). I wonder if it would be possible to mount the cheaper kind in the hole where the original type goes and somehow snake the other power wire behind and leave the ignition lock conduit thing disconnected. If the coil is the same diameter it might fit in the coil bracket and look kind of stock. Has anyone done that?

I have noticed that the later cars have the coil mounted on the loom thing that routes the igntion cables. I really would rather keep mine in the stock location.

Here is another question: When I removed my old ignition cables I could not find a way to separate the two sides of the ignition cable loom thing so I removed the contacts and boot from the ends of the cables. I have some new cables but I don't want to take them apart. Is it actually possible to separate the two halfs of the loom thing or do you really need to build the cables on the car?

Here is how mine looks:

http://www.pangalacticconsortium.com/cars/PlymouthGallery/imgpages/image041.html

Thanks,

Rebecca

[greg g]

Yep you're looking at a mid 30's anti theft system. Makes it difficult to hot wire the car from uer the hood. The outside terminal feeds the dizzy. The inside armored cable has been addressed a time or two. I believe one person did a bit of work with the dremel, freed up the wire, replaced the coil in the firewall position snaked the new wire through next to the coil and then reattached. Ifn goes to neg, pos to dizzy.

As for the wires can you remove the boots feom the dizzy ends and snake the new ones through then replace the boots??

[n1gzd_plymouth]

Yep you're looking at a mid 30's anti theft system. Makes it difficult to hot wire the car from uer the hood. The outside terminal feeds the dizzy. The inside armored cable has been addressed a time or two. I believe one person did a bit of work with the dremel, freed up the wire, replaced the coil in the firewall position snaked the new wire through next to the coil and then reattached. Ifn goes to neg, pos to dizzy.

As for the wires can you remove the boots feom the dizzy ends and snake the new ones through then replace the boots??

Regardin boots, I tugged on one of them tonight and decided not to pull harder until I am sure that the loom thing does not come apart. Perhaps if I put some DC4 compound on it I can slip it off. It does look like the cables with the connector on it will fit through the loom without the boot so I would try that first before cutting the cables off.

Regarding the coil.

so, the anti theft cable on the back is not the negative connection (that is a separate wire that is connection in addition to the anti theft). If this is true and I use a modern coil I can disconnect the anti theft cable and just leave it dangling back there (wire tied out of the way or removed - I think that it can disconnect from the switch) and then as you suggest, find away to snake the negative wire (carefully so it can't pinch against ground) to the back of the coil. I think that I woudl rather be set up to use a readily available coil incase I get stuck somewhere. I could just make sure it is a black one so it looks more or less correct.

Rebecca

[Jim Yergin]

Rebecca,

On my '41 P12, the anti-theft cover on the inside end of the coil is held in place by some metal tabs. If you bend those tabs up the cover comes off and you will be able to disconnect the wire that runs from the ignition switch to the coil. That wire is hot when the ignition switch is on. I think the original coils had the firewall bracket attached so that they are one piece. There are seperate collars to use with the replacement coils. I may have an extra collar if you need one. You should be able to do what you propose by connecting additional wire to the end of the wire you disconnect from the inside end of the coil so that you have enough length to pass it through the firewall to the top side of the later model coil.

Jim Yergin

[Don Coatney]

Rebecca;

Is your battery still installed with a positive ground? I thought I saw an alternator on your car. If you are running negative ground (not stock as your car was positive ground from the factory) then the polarity on your coil must also be switched. This may be why you had some poor running issues.

[n1gzd_plymouth]

Rebecca;

Is your battery still installed with a positive ground? I thought I saw an alternator on your car. If you are running negative ground (not stock as your car was positive ground from the factory) then the polarity on your coil must also be switched. This may be why you had some poor running issues.

I have a 6 volt positive ground alternator. I am double checking everyting as go go through this car because I completely trust the work of the previous owner (who did not own the car very long and hardly drove it). I have driven the car only once myself.

I have also verified that my battery is wired up for a positive ground system.

Rebecca

[n1gzd_plymouth]

Rebecca,

On my '41 P12, the anti-theft cover on the inside end of the coil is held in place by some metal tabs. If you bend those tabs up the cover comes off and you will be able to disconnect the wire that runs from the ignition switch to the coil. That wire is hot when the ignition switch is on. I think the original coils had the firewall bracket attached so that they are one piece. There are seperate collars to use with the replacement coils. I may have an extra collar if you need one. You should be able to do what you propose by connecting additional wire to the end of the wire you disconnect from the inside end of the coil so that you have enough length to pass it through the firewall to the top side of the later model coil.

Jim Yergin

good. Can you confirm that if I disconnect the anti theft cable from the coil it will have no effect on the ignition switch (it only effected the coil which I am replacing with one that does not have that feature)?

Rebecca

[Jim Yergin]

Rebecca,

I am not sure I understand your question. If you disconnect the antitheft cable it will affect the ignition switch to the extent that the switch will not be connected to the coil and you won't have any ignition. If you are running some other power line to the coil then it won't have any other affect.

Jim Yergin

[TodFitch]

If you are going to break the ignition/cable/coil assembly apart, it is easier to work on the tabs that hold the cable to the coil if the whole thing is out of the car.

At least on the 1933, you need to remove everything from the engine compartment side. Remove the wires from the ignition switch, remove the two nuts holding the switch in place, remove the three bolts that hold the coil to the firewall, then slide the switch and cable out through the coil hole.

I personally haven't figured out a save way to remove the armored cable from the switch, but it is possible to break open the connection between the coil and the cable.

By the way, just because it is original doe not mean the coil it bad. I have had a car that had a bad coil but it is a pretty rare thing. So I have a spare and have left the original in my car.

[Young Ed]

My truck still uses this system. I am still running a coil thats welded to the bracket too. I think these are the original ones that are welded. Somehow we were able to sorta unscrew that armored cable from the ignition switch and replace the wire. The cable was then put back together. Sorry that was 7 years ago so the details are a little sketchy

[n1gzd_plymouth]

If you are going to break the ignition/cable/coil assembly apart, it is easier to work on the tabs that hold the cable to the coil if the whole thing is out of the car.

At least on the 1933, you need to remove everything from the engine compartment side. Remove the wires from the ignition switch, remove the two nuts holding the switch in place, remove the three bolts that hold the coil to the firewall, then slide the switch and cable out through the coil hole.

I personally haven't figured out a save way to remove the armored cable from the switch, but it is possible to break open the connection between the coil and the cable.

By the way, just because it is original doe not mean the coil it bad. I have had a car that had a bad coil but it is a pretty rare thing. So I have a spare and have left the original in my car.

Well, keeping my coil is certainly the easy route. I just need to find one of those screw in ignition coil connectors to swap onto my new ignition cables that have the newer style connector. I still need to understand how this is configured so that I at least know what the options are if the coil fails.

Do coils normally work not not work? Is it possible to have a weak spark due to a coil that is going bad or is it OK or NOT OK?

Rebecca

[Jerry Roberts]

Often when a coil goes bad , they will malfuntion after the coil warms up . Also others have had a problem with old insulation on the wire inside of the armored cable - it gets brittle and falls off causing a short against the armor .