48 New Yorker - Electrical Question

Dumb question...maybe. My 48 NY C39 uses a 6v battery, right? I hope so because I already bought and installed one. The posts on the battery are clearly marked +(large post) and - (small post). The cables are similarly sized. But I am confused because the negative cable runs to the starter and the positive to the generator/alternator? Is this what is meant by positive ground?

Thats correct!

OK here's another electrical question. I'm having a spark issue...as in I'm not not getting any. I've changed the plugs and will change the wires, rotor, condenser, and points next weekend (I'd sneak out to the garage tomorrow but might get into a bit of trouble with the whole mothers day/anniversary thing). This will work out, becuase I need to change the oil anyway and thanks to this forum (Bob!), I've found a NOS oil filter and it should be here by then. Once all this is done I can start on the process of elimination and try to resolve the spark issue. But here's the question....what is this? It is attached (after market?) on the wire leading from the ignition coil to the distributor. Quick research indicates it's a interference capacitor for the radio. I suspect it may be a source of some of my problems. When I replace the wires, do I need one of these?

I should have been more clear. It is not attached to but actually grafted on (by threaded screws) to the wire. I would upload a picture but can't get it to work.

It does look like a radio suppression resistor. I had a funny problem on a similar car (49 Chrysler six) not long ago. It would fire for a few seconds then die. It turned out to be a faulty one of those.

I replaced it with a piece of resistance wire I had handy. The engine started and ran like a champ.

The resistance wire I mentioned, is a standard carbon core ignition wire used on practically all cars from the late 50s to the present time. I happened to have a new wire left over from a set I had installed so I cut it to length and put it on the Chrysler.

By doing this, I kept the necessary radio suppression in the wiring. This is usually all that is necessary, you can use solid core wires to the plugs and get no interference. This is the best way to go on cars that were not built for carbon core wires.

If you have no spark you can diagnose it very quickly using nothing but a 6v test light or multi meter.

Are you getting current to the coil? Yes No

No - turn on ignition, now do you have current? Yes No

No - trace wires, test battery till you find the problem

Yes - is current coming out of the coil and getting to the points?

No - faulty wiring or coil

Yes - does the current switch off and on as the points open and close?

No - faulty points, dirty points, faulty wire.

Yes - Do you get a spark from the coil wire if you hold it close to the engine? Or stick a spark plug on it and ground it to the engine?

No - faulty coil, condenser, or wire

Yes - connect coil to distributor. Don't forget to put in the rotor.

With the spark plugs out and lying on the engine, turn the engine over. Do all the plugs fire?

No - check gap and clean plugs by sandblasting, or replace them. Check wires for resistance. Solid core wires should have no resistance, carbon core 5000 ohms per foot.

Yes - put the plugs in and go for a drive

Still won't go - check timing. Also check that the wires are connected to the right plugs. They are easy to mix up.

If you have a good spark on all cylinders, all at the right time, your problem is not in the ignition system. You need to look elsewhere like the carburetor or compression.

This is entirely scientific or mechanical. An engine that has good compression, the right mix of gas and air, and a good spark at the right time, MUST run. It has no choice.

Rusty - Thanks! I will be back in the garage by the end of the week and will have this checklist with me. Also, the mail man brought me the long awaited shop manual which I will read from cover to cover!

Dumb question...maybe. My 48 NY C39 uses a 6v battery, right? I hope so because I already bought and installed one. The posts on the battery are clearly marked +(large post) and - (small post). The cables are similarly sized. But I am confused because the negative cable runs to the starter and the positive to the generator/alternator? Is this what is meant by positive ground?

Now I am confused, I am thinking the positive battery cable (large post) should go to ground (chassis), and the negative cable (small post) should go to the starter solenoid.

To put it simply, positive ground looks like the battery is hooked up backwards compared to what we see in today's cars.

Yes. That's what I believe. Sorry if I caused the confusion. I just wanted to make sure that I want booking things up wrong.

At the moment I only have the one car that is pos ground. I get confused all of the time when working on it. But with some common sense that are not that bad.

It just seems wrong to be looking for voltage with the VOM hooked up backwards.

At the moment I only have the one car that is pos ground. I get confused all of the time when working on it. But with some common sense that are not that bad.

It just seems wrong to be looking for voltage with the VOM hooked up backwards.

Switch the leads on the multi meter. Then red is hot and black is ground. That is what I do. Saves getting mixed up as long as I don't forget to change them back lol.