Why did they only use one for Leading and 2 for Trailing???

STEPHEN

 

The leading can fire at the same time, so they could use one double-ended coil. It's less parts and works just as well. A little better, actually, since the waste spark happens as the exhaust stroke begins and helps clean up emissions a little.

A popular mod for 1st-gens is to use the leading pickup to drive an MSD which fires two separate coils. This bypasses the distributor entirely. A double-ended coil would work but in our case it's actually easier to just buy a pair of $30 coils.

 

So does that one leading coil have as much "power" as the 2 trailings added together???

STEPHEN

 

Damn Peejay. I alway knew this, but you just explained it in two little paragraphs in a way that made it crystal clear. Now I understand the how and they why. !

Thanks.

 

I've been meaning to ask this for sometime now. Thanks Stephen and peejay.

 

There's a whole argument about whether the double ended coils' shared output is as powerful as two seperate coils under heavy engine load (or idle for that matter). It's cheaper to use a doubled coil, but is it really better than two seperate coils on the Leading side? I tend to think seperates are the way to go.

 

The spark energy for the "waste spark" is lots lower than the spark energy required for the firing chamber. The dual-ended coils are so powerful that it really doesn't matter.

To give you an idea how strong the dual-ended coils are, the quick-n-dirty way of testing them is to yank the plug wires off and crank the engine. Should be a big fat blue spark arcing across the ~1" gap. Can't think of many coils that can jump a 1" gap that strongly!

 

I got bit by a leading coil on my first TII (long story). I can attest that they are stronger than a normal old 12V single coil (my old Ford truck used to like to bite me too )

 

Damn, man you need to stop raising attack coils, they are dangerous haha

STEPHEN

 

Yea, I was kinda wondering if the 2 posts share the power where if you didnt use one plug would the other get all the power??? If that was the case I could hook up another L coil and have 2 (one for each L plug) and they would be much stronger.

I probably doesnt work like that, I bet they are individual but just in the same box with one connection or something alog those lines.

What do you guys think???

STEPHEN

 

Yes it is easier to fire a coil when it's in wasted mode, but that's just it: on a doubled coil, more of the spark energy would go through the wasted side because it's easier to jump due to the lower pressure near the plug compared to the non wasted rotor.

Unless the unburned AF mixture actually is lower PSI-wise than the still somewhat burning wasted side? This also depends on whether the high tension side of the double ended coil has two outputs, or two seperate secondary windings. I don't have one of those coils handy to test with a continuity tester.

 

Does anyone make a better 2 post coil? I remember looking for one a ways back and the only thing available at the time was the MSD motorcycle coil. I would think by now with the rise in the import scene this would be available but have not looked lately.