View Full Version : TR4/4A Quick question on TR4 battery

05-02-2008, 11:42 AM
Need to get a battery for the TR4 BUT the car is at a shop and I've forgotten which terminal is on which side.

If you are looking at the engine bay from the front (radiator) which side is the positive terminal on?

I 'think' it is the right hand, drivers side.


05-02-2008, 12:00 PM
If you haven't converted the ground from positive to negative, the positive side or ground is on the drivers side. Negative then runs down by the carbs to the starter solenoid.

I think there's room for the terminals to be on either side, just depends if you want the terminals to be close to the hold down bar, or close to the bulkhead.


05-02-2008, 12:02 PM
Thanks Randy!

05-02-2008, 12:28 PM
If you haven't converted the ground from positive to negative,

I would add if the previous owner had not converted to negative ground either. My previous owner did the conversion on my car so it is now negative ground.

Lou Metelko
05-02-2008, 01:13 PM
Both the TR4 (positive ground) and the TR4A (negative) used the same size battery. It was just turned around; posts in front or at the rear. A group 27 (original) size fills the shelf much better than the more common group 24.

Lou Metelko
Auburn, Indiana
65 TR4A

05-02-2008, 01:49 PM
Thanks guys - appreciate it!

05-02-2008, 04:05 PM
I have a service bulletin T-65-15 about grounding. It is 3 pages long and starts with:

Current practice on vehicles of British design is to ground the positive
terminal of the battery, while other countries have retained, or reverted to,
the use of negative polarity for the ground circuit.
With the increasing use of polarity sensitive devices, such as silicon diodes,
transistors, and electronic components in vehicle electrical equipment, there
are advantages to be gained from the early adoption of a standardized vehicle
grounding system, particularly in the service field.
The reasons which originally prompted the adoption of positive ground on
British vehicles, although still being valid, are now of less practical
Importance owing to improvements in electrical design. In the interest of
standardization most vehicles manufactured in England will in the future change
over to a negative ground system.
Two manufacturers have already introduced production models with negative ground
equipment. These are the David Brown 3 cylinder, 880 implematic tractor, with
conventional D.C. equipment and the Jaguar 4.2 litre Mk. X and E-types with
A.C. equipment. This trend will undoubtedly continue until eventually all
British vehicles have negative ground electrics.

Geo Hahn
05-02-2008, 06:30 PM
A group 27 (original) size fills the shelf much better than the more common group 24...

Quite so... but the 24 is the one readily available from W-Mart for small money. It doesn't look half bad if stripped of its modern labels and the 3-hole caps replaced with a set of 6 vintage caps.

For the group 24 I use a couple of wood spacers on each side to keep it from sliding around.