any difference for a positive or negative ground front mount distributer on 8n

[trapboy]

do I need a positive ground distributor for the 8n or just wire the tractor that way, correct ?

 

[Jim.ME]

do I need a positive ground distributor for the 8n or just wire the tractor that way, correct ?

Just wire as negative ground, Correct. If you have a generator you will likely need to polarize it to negative ground.

 

[Jim L WA]

Jim.ME means to polarize the generator. The distributor doesn't care.

 

[soaked]

Hi trapboy, are you using your 6 volt positive ground EI, or going to points?

If pertronix 1247ap6, it must be positive ground, or it will fry.

 

[Jim.ME]

Yes, I meant polarize the generator.

To reinforce soaked's post; If you have a positive ground 6-volt EI, you left out some very key information when you asked your question. A points ignition would not care about the ground. You cannot just swap an EI unit between positive or negative ground; the unit must be the correct ground for the tractor. If have a positive ground EI now and you want to go to negative ground; you need to purchase and install a negative ground unit.

 

[trapboy]

Hi trapboy, are you using your 6 volt positive ground EI, or going to points?

If pertronix 1247ap6, it must be positive ground, or it will fry.

No I am going back to points

 

[trapboy]

Hi trapboy, are you using your 6 volt positive ground EI, or going to points?

If pertronix 1247ap6, it must be positive ground, or it will fry.

I am going to points

 

[soaked]

Here is a diagram for 6 volt positive ground, like it was from the factory.

 

[trapboy]

Here is a diagram for 6 volt positive ground, like it was from the factory.
View attachment 161558

Thankyou!

 

[soaked]

Happy to help
Did your EI end up failing the bench test?

 

[trapboy]

That set up looks much less engineering than what pertronix gave me. I have not had time to get to test it. If the igniter fails, then it is back to points and copper plug wires.

 

[soaked]

Can you post what Pertronix gave you?

 

[trapboy]

I will try but not tonight, it is out in the barn. I already got a new aftermarket distributor and plan on going back to points. I may change to a negative ground. I just have to polarize the generator, change the battery terminals. I think? I will not get time until Friday to work on the beast again. If I get rolling in the am I will post the directions from pertronix. It looks like I need 4 hands to do all the functions on that one test and it is not easy to get to the distributor when installed.

 

[soaked]

I have seen a 12 volt neg ground Pertronix Loaded Voltage Test, do you have a 6 volt pos ground version, or other?

Before installing your new distributor, check the point gap ( .015 ), and clean the points contact surfaces. The corrosion prohibiter on the new points isn't conductive, so no spark, if not cleaned off.

What is a benefit to going 6 volt negative ground? Seems to me that would give a weaker spark. 6 volt coils are made for positive ground.

Click on and see JMOR (RIP) post here-

J

Post in thread 'Tale of two,Positive Grnd'

Aug 24, 2023

(quoted from post at 15:26:23 08/24/23) I've searched posts with many contributors such as JMOR and souNdguy and others and I'm looking for additional verification pertaining to the NAA 6V Pos ground.

Owned for 30 Yrs a Fergy TO30 6V Pos Grnd, and coil terms have a + and - . The + goes to the Distributor. Runs great always has.

Also a 53 NAA Jubilee 6V Pos ground and the Coil that came with it and reinstalled had [b:9e18d603b3]Bat[/b:9e18d603b3], and [b:9e18d603b3]Dist[/b:9e18d603b3] stamped on it. Coil only fits one way with dimple located to hole in bracket. Terminals are on...

• JMOR

 

[trapboy]

I have replaced the old distributor, with a new aftermarket distributor. cleaned the points checked gap, replaced the resistor wires and put a set of copper wires on.at first I had reversed 3 and 4. tried to start but just one burp. found the firing order problem, Corrected the plug wiring at cap, checked all plugs. they seemed fine . turned on ignition and the tractor has never ran this good. Knock on wood, it is an 8n and 75 years old. I had thought the distributor had a little knock in it. My uncle had this machine for 10 years and had some one different work on the points replacement cap rotor,.once or twice a year and it aparently was a tired wore out distributor. We are currently running original 6 volt pos ground. I will run the test on that expensive EI. and post the test sheets from pertronix. It is running and I need to get some other work done.

 

[soaked]

Thats great you got it running!
Looking forward to the pertronix info, and a verdict on your EI.

 

[HarryVanderpool]

Maybe you should run it for a year on the stock ignition and then decide if you want to swap out the system that has worked fine for 75 years?
If its's not broke, don't fix it?

 

[trapboy]

That is my thought. I may just get the pertronix ready