New 36 Plymouth coupe with some questions

[Guest n1gzd]

Although I have purchased the car my maintenance manual has not come in the mail yet.

1) Does this car have a positive or negative ground. It appeared to be wired as negative ground but I thought that the old mopar cars had positive ground.

2) The vin number on the title starts with "P2". Where on the car would I find a number with this format. The number on the right door jamb is different and does not start with a "p2". I can't just start searching on the car because I don't have it yet (but I have seen it in person). Is it possible that the title is using the number from the engine block or frame? It is possible that they changed the door and forgot to swap the tag but the number on the door does not include "p2" in front of it.

I am sure I am going to have more questions.

Thanks,

Rebecca

[Guest n1gzd]

I am pretty sure that all mopar cars had 6v positive ground until some time in the 50's. Please correct me if I am wrong.

However, my new 36 has a 6v alternator and I am suspecting that the previous owner converted it to 6v negative ground (I might switch it back to generator I am still deciding).

I just want to make sure I know how the car was originally in case they did something wrong and this knowledge will help me diagnose it.

How about my vin # question?

Rebecca

[Mika Jaakkola]

Atleast my '39 Dodge had a negative ground as well my '38 Dodge truck. I've heard that Chryco used + ground but never seen one live

If your car has - ground, I do think that's original. Because - at my knowledge - if you convert the system to "other" ground that it really is, the starter motor turns backwards(if you don't remake the coil in it), and then you have a problem.

Yep, sometimes they used engine number on titles.

[Guest n1gzd]

Thanks for the info. I will hopefully get my shop manual soon so I can resolve this.

I will check the number on the engine ASAP (when I get the car home). It would not surprise me if the number was from the engine (because it starts with P2, I think that a P2 vs P1 had to do with the engine.

Rebecca

[keiser31]

Your P2 number will either be on the cowl or passenger side door post at the hinges. There would not be serial number on the door itself.Most MOPARS are negative ground.

[hwellens]

<span style="text-decoration: underline">Positive Ground</span>. The P2 should be the prefix of your engine serial number. Look on the bossing under the cylinder head at number one cylinder. Information attached.

[Guest elmo39]

it should be positive ground , its easy to check which way it has been wired , simply connect the battery and turn the ignition on , if the ammeter shows a discharge you have it connected as it was wired , if it shows a charge just change the wires around on the battery, doing this test will not harm your wiring or battery. just as with any ignition system do not leave switched on to long without the engine running

[Guest n1gzd]

thanks for the info. I think that I now have the info that I need. I know how to tell which way the car is wired, what I was asking what the car should be not how to tell what it is (I don't know if the car is wired correctly - based on somethings that the seller said).

I am going to have lots more questions.

Rebecca

[Guest brian]

Rebecca:

All Chrysler products were positive ground through 1954 - no exceptions that I have ever heard of. your 36 should definitely be positive ground.

Brian

[Guest n1gzd]

Yup. I now have the car and have confirmed that it is positive ground. The seller was very confused.

Rebecca