TR2/3/3A Positive Ground Question

[SteveBones]

I have a couple of questions regarding Positive ground set up for my TR3a.

A little background first. I had 3 Triumphs and just sold one. I also just purchased new from Britishwiring Positive and Negative Battery Leads.

Now I confused myself and can not remember if my remaining TR3a was previously positive or negative ground.

So now to my questions:

1). Moss talks about "polarizing" the generator if it is new. I do want my set up to be positive ground regardless of what it now. I will polarize the generator per Moss motors recommendation. For future reference, do I really need to?

2). Wire lead (2) connections to the coil. What is the set up for the wire from the distributor? If positive ground, does this lead wire (white with black strip and connectors at both ends) go to the positive (+) on the coil? And the wire from the wiring harness go to negative (-) or is it the other way around?

Thanks in advance for your help.

 

[TR3driver]

1) If you are keeping the same ground polarity, and the generator has not been off, there is usually no need to repolarize it. But the process is quick and certainly won't hurt. Otherwise the generator may come up to voltage with the wrong polarity, which will cause a big current surge when the cutout contacts close.

2) Original coils were not marked + and -. But for an aftermarket coil and positive ground, the - terminal gets the white wire from the harness, and the + terminal gets the short jumper to the distributor.

Actually, in my experience, it doesn't make enough difference to notice. The issue is only that the plugs are a little easier to fire when the center electrode goes negative. But we're only talking 1% or 2%, and the system normally has much more margin than that.

 

[SteveBones]

Perfect! Exactly what I need.

Thank you Randall

1) If you are keeping the same ground polarity, and the generator has not been off, there is usually no need to repolarize it. But the process is quick and certainly won't hurt. Otherwise the generator may come up to voltage with the wrong polarity, which will cause a big current surge when the cutout contacts close.

2) Original coils were not marked + and -. But for an aftermarket coil and positive ground, the - terminal gets the white wire from the harness, and the + terminal gets the short jumper to the distributor.

Actually, in my experience, it doesn't make enough difference to notice. The issue is only that the plugs are a little easier to fire when the center electrode goes negative. But we're only talking 1% or 2%, and the system normally has much more margin than that.