• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR2/3/3A Coil wiring

Share this page

S

Sarge

Freshman Member
Offline
the wiring chart has "CB" and "SW" notated - which wire is which? what does that stand for? Which is positive and which is negative?

Thanks for your help !!
 
My guess is cb is circuit breaker for distributor - and sw is switch for +on a negative ground car.
Tom
 
Contact Breaker & SWitch - in my experience those designations were on coils back when most Lucas-equipped cars were positive ground.

Later, when negative ground cars came into vogue, the markings were changed to + & -.

I think you will be okay by regarding CB = + and SW = -.
 
trglory said:
I'm not sure it makes any difference one way or the other.
Click to expand...

Generally, it makes no difference, as most of the time it will run regardless of the how the polarity of the coil is wired. However, there is a difference in how effectively the spark jumps the electrodes in the spark plugs depending on the polarity. Read this link for a full explanation...

https://mgaguru.com/mgtech/ignition/ig104.htm
 
Back
Top