[TazandChevyfun]

Recently went into debt, and bought my first new Ford Ranger (not new I guess it's a 99 , still not sure why I bought a Ford) that has a fuel injected, 4 cylinder, that looks just like a Pinto 2300, that has 2 plugs per cylinder. Really runs good, but I don't understand why the 2 plugs? I was just wondering if anybody had an answer. Or if anybody has had problems with this type engine. I'm stuck in the 60-80 year range as far as engine and tech stuff.

[F-1 Rodder]

Dual plugging heads is very common in building high compression high performance motors. I have put dual plugs into a Porsche race motor and had a set of dual plug heads on a BMW twin motorcycly for years. The reason for doing so is to shorten the flash channel inside the combustion chamber. Sometimes this is due to using a raised or humped dome piston to raise compression or to channel gasses out after detonation. The dual plugs compensate for the fact that the flash channel is obstructed by a raised piston dome. Dual plugging generally can reduce the tendancy toward pre-detonation and may allow the use of higher compressions or the use of lower grade fuels. I think you would see it more were it not for the complications of having twice as many components inside the ignitions system. I am sure there is more to this than I understand, but I think my answer is in the ballpark.

[madingo]

OK, here is the Ford reason they did it. Emissions-one side is primary, the other is like a redundant deal, much like a long spark of ans msd. High compression they are not. Our chips sell like hotcakes for them.