Single coil, dual plug wires?

[Brettw]

Something just dawned on me. Every time someone loses a coil on a Kohler KT, they are shocked by the cost of a replacement. Then I have heard people suggest a Harley coil, also not inexpensive. However, my understanding is, that both plugs fire on every other stroke, so in other words, even though the cylinders fire on opposite combustion strokes, both plugs are being fed spark even when not needed.

What would prevent using a single auto coil, and then using a split one into two plug wire? If such a thing exists? Would this work and if so, wouldn't it be much cheaper with many many possibilities for parts available, both new and used?

[goatfarmer]

Interesting concept, but I've never heard of a split plug wire.

[PhanDad]

I would think the spark intensity would be effected and/or only 1 plug would fire if 1 plug had a little less resistance (slightly smaller gap maybe).

[yukon]

ive heard the harley coil would work

[HubbardRA]

If you use one coil to two wires, or even two coils fired from the same set of points, only the strongest one will fire. In other words, most of the power will go through only one wire to one plug. A friend of mine tried it and could not get the engine to run smoothly. We ended up replacing that setup with a Kawasaki dual coil. It ran perfectly. This was on an Onan.Not much difference between a single coil and a dual coil. In a single coil the output side has one lead going to a plug and the other to ground. In the dual coil each wire goes to a plug.

Motorcycles have been using these dual coils for many years. Pull one of a junk bike and use it on your two cylinder engine. It will work fine and won't cost very much. Just make sure the center bar of the coil is grounded to the engine for maximum spark.

[BLT]

How could you fire a "V " twin as the firing would have to be staggered or you have a staggered throw crankshaft and that won't be cheap.

[rokon2813]

quote:Originally posted by BLT

How could you fire a "V " twin as the firing would have to be staggered or you have a staggered throw crankshaft and that won't be cheap.

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id="quote">

id="quote">Bob, it is my understanding that both plugs fire every time. While one side fires at the beginning of the power stroke, the other fires at the beginning of the exhaust stroke so in effect does nothing since the exhaust valve is open.Next revolution, the opposite side is on power and vice versa.

[midnightpumpkin]

Originally posted by rokon2813

quote:

id="quote">A KT 17 is not a V twin, it is a horizonataly opposed twin, it is called a waste spark ignition system and works as Rokon has pointed out.I have used an AC Delco D555 coil with a CR-107 ballast resistor on these engines with great success. These coils are available at very cheap prices. They were used in most GM vehicles from the late 80's through the 90's.John U

[BLT]

John I know about Kohlers and Briggs opposed, but was wondering how you fire a Harley.

[HubbardRA]

Not totally sure how a Harley fires, but it looks like a V-twin would need the coil to be triggered at two different points. The cams would be set up so that the pistons fire on opposite rotations, so the actual cylinder combustion would not be too close together. They may not produce power 360 degrees apart, but it would be 315 degrees on a 45 degree V.

The same coil would work in this scenario as would work on an opposed twin, or side-by-side twin.

[JimDk]

I had an old Harley "K" back in near pre-historic times. If my dim memory serves me, I recall two un-equaly spaced lobes on the distributor cam.