why 2 plugs per cylinder?
I did the conversion on my R90S. There was a time during the conversion to unleaded fuel when premium was not available. Dual plugging allowed the use of regular because two flame fronts shortened the time to complete combustion requiring retarding the spark timing significantly.Dual Plug conversions were popular with the BMW airhead flat twins. More complete combustion.
I regularly rode out of my area and even Amoco did not convert all their stations from leaded premium to unleaded premium immediately. Believe me, finding premium was impossible in many locations for quite a while. People bought bottles of octane booster to get them through the transition. Those with unhardened valve seats pretty much lost their engines. Shops did a big business in dual plugging and hardened valve seat replacements for a while.you didn't have Amoco stations in your area ?
it may not completely eliminate detonation but, it helps. (not quicker) helps by igniting all fuel at the same time. so as there will be no small deposits of unburnt fuel on the outside edge of the flame, which can ignite on their own due to heat & pressure and cause detonation. its a "band aid" for not having a high enough octane fuel.Two flame fronts can burn the mixture quicker and that can eliminate detonation. Two plugs per cylinder were originally considered a "band aid" ... ...
My 1976 CVCC Honda (Civic) engine got around the ignition of a very lean mixture by having a separate pre-ignition chamber (in which the spark plug fired), with it's own small intake valve and separate "barrel" in the carburetor. The flame front would then travel into the main chamber to burn the leaner mixture there. Other than unrelated problems with the engine and car, it worked very well, and gave efficient and clean operation.In laymens terms the second plug is used to insure the mixture in that cycle has a better chance of being ignited. With the lean mixtures ( especially at cruise ) it is possible that the mixture in the area of one of the spark plugs is too lean to fire ( or sometimes fire but "die out" because mixture ratio won't promote a flame front ). The other plug likely has a better chance of igniting the mixture.
even Amoco did not convert all their stations from leaded premium to unleaded premium immediately.
I didn't know that. Still there were places in my travels that had no Amoco stations and no premium of any kind. In 1976, before the lead free era, I had to put regular in my CB500 on a Colorado trip. The altitude saved me.Amoco Premium never had lead in it from day one, long before the requirement for unleaded
Twin spark ignitions do indeed BURN the mixture quicker because the combustion process starts in two areas. Not designed solely to eliminate detonation but to increase the "quality" of the combustion event. That means decreased bad emissions, better fuel economy, more power, and less detonation.it may not completely eliminate detonation but, it helps. (not quicker) helps by igniting all fuel at the same time. so as there will be no small deposits of unburnt fuel on the outside edge of the flame, which can ignite on their own due to heat & pressure and cause detonation. its a "band aid" for not having a high enough octane fuel.
as I recall, it was a very popular brand at marinas, not sure it was to keep lead out of the water or that the high powered 2smoke outboards prefered itAMOCO premium ( cannot remember about their regular grade ) was indeed lead free. Called white gas by some, it was good to burn in Coleman lanterns and stoves.......but of course that is another topic
8 point and dual coil iircSo did the '86 model, not that you had it ...
I assume the 2 plugs per cylinder in the nissan fired 1 after another, since it had an 8 point distributor and don't remember linking inside the cap.