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TR2/3/3A TR3A TSL45911

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tmc

tmc

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I'm at the wiring - electrical - fuel - cooling system stage of my restoration. At the moment,I'm trying to remember if this car was positive or negative ground. I have pictures of the firewall with everything in place, but I cannot read the + - symbols on the battery posts. It appears to me the battery is in "backwards" and the negative post is grounded, with the positive post connected to the solenoid. The voltage regulator that it came with is a later model with blade attachment; however, I have the older version to replace it with. All the above leads me to think it's been "converted" to negative ground.

It appears to me from my reading that this car was originally positive ground, which was true until after TS60001. I don't plan to add a radio, or electronic ignition, or whatever, this is a restoration to original except for some "sensible" upgrades.

What are the pros and cons of positive or negative ground, other than the obvious (it's different than most other cars and jump starting it wrong can be disastrous)?
 
The TRs were positive ground up until the TR4A, so your car would definitely have been positive ground originally.

Other than the obvious, there's no disadvantage to keeping it stock, lots of people do.

One caveat, though, if you ever get a jump start; be sure that the cars don't touch! You'll also want to keep a close eye on whoever is doing the jump; the tow truck driver or whoever might not look at the marks with potentially disastrous results.
 
You'll need to check if your generator is polarized negative or positive earth.

I'm not sure if you can tell with it off the car, but an auto elec would be able to spin it up and find out.

Viv.
 
When he installs the battery, and steps on the brake, won't the ammeter tell him?
 
mrv8q said:
When he installs the battery, and steps on the brake, won't the ammeter tell him?
Click to expand...
No, but starting the engine sure will.

However, if there is any doubt, just repolarize it. Only takes a few seconds, easily done on the car.
 
The one other downside (that I live with) for the + ground is that the commonly available battery cables don't fit well. The braided ground I got at Pep Boyz has to have it's clamp spread wide to fit over the positive post and the solenoid/starter cable I'm using is expecting a post larger that the negative post offers. As I noted, I just live with it.

The electrically-challenged PO I got the TR4 from had actually installed the battery backwards -- converting the car to negative ground by brute force... no polarizing, no changing the polarity plug on the radio. Started and ran fine and, when corrected, even the radio still worked. Not recommended but apparently under some circumstance the generator will polarize itself as needed.
 
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