Negative Ground

[Ned]

No. Only if they were grounded. Much like when you have 2 batteries in series it works fine.

[CaMpylobacter]

you're grounded

now get off the internet little neddy and get into your bed

[forced]

In an ignition coil there are 2 windings. The LT winding runs between the + and - terminals. The HT winding runs between the HT connection and one of the other terminals. It's not hard to figure out that swapping the terminals will affect the HT voltage produced and so make it "wrong" even if it's only a little bit wrong. Part nos for coils (old lucas ones) also depend on whether they're + or - earth.

If coils were marked as "battery" and "points" there wouldn't be confusion.

Of course someone might think that the spark now travels in the wrong direction. The answer to that is to look at how wasted spark works.

Steve

[Ned]

you're grounded

now get off the internet little neddy and get into your bed

So how is something that connects to the road through rubber grounded?

[Borgweiser]

In an ignition coil there are 2 windings. The LT winding runs between the + and - terminals. The HT winding runs between the HT connection and one of the other terminals. It's not hard to figure out that swapping the terminals will affect the HT voltage produced and so make it "wrong" even if it's only a little bit wrong. Part nos for coils (old lucas ones) also depend on whether they're + or - earth.

If coils were marked as "battery" and "points" there wouldn't be confusion.

Of course someone might think that the spark now travels in the wrong direction. The answer to that is to look at how wasted spark works.

Steve

Actually got it pretty right for once, infact most lucas coils are marked CB (contact breaker- and SW (Ign switch). A coil will work whatever way, but if you want it right it depends on the coil, older types ran thicker windings and also the addition of ballast resistors fucks everything- then you have to swap them round.

Just leave positive earth and isolate stereo from the body = win and working ammeters.

Also some ammeters will catch fire if you change polarity, even if you swap the leads. Usually happens during a long run. Smiths are good for this, just a point to be aware of.

Alternators are also on my list along with spoilovers, pintos, bright coloured bateries in engine bays, silicon leads, stainless wire wheels, 2K paintjobs and car club badges- list of things that ruin all pre 60's and most newer classics IMO