Hi all,
Recently in tracking down a problem with my 460, I have been learning about the part of my engine I know very little about: the ignition. In this, I have a couple questions that I am still unclear on.
What is the difference between a more traditional rotor/cap/distributor system (magnetic or points) with a coil, and one of the newer ones that has that same setup, but has a "ignition box" with tons of fancy wires coming out of it? I understand that they produce a multiple spark per cylinder, but that seems like a lot of electronics and wiring for just that. Is it really that simple?
Second question of similar value - My BBF 460 has a resistor on the positive lead going to the coil. I have read that some use that, and some don't. question is, what does this do, what is it's resistance value, and if you do not have this resistor, are the two leads from the coil simply positive and negative from the battery? (well, obviously not directly to the battery on the positive side, but rather thru the ignition key in some manner I would presume...)
Anyway, Just a few questions, and I'm sure I'm not the only one that does not have all the facts on ignition nailed down, so I thought I'd extend my potentially bonehead question of the day to the masses for review
Well, no one else is going to respond so I'll give it a try. Points and basic electronic ignition both break a circuit in the coil to allow a high voltage spike to go through the plugs to ground. The reason for all the wires or capacitive discharge ignition is to fire the plug exactly at the proper moment with maximum voltage throughout the rpm range. Points and electronic ignition will fire the ignition on a 460 with under 10 to 1 compression up to about 4000rpm with no problem. Above that points start to bounce and the signal from a car type electronic ignition will start to flutter, causing eratic plug firing. MSD or "cd" type ignition gives a multiple spark within the dwell range at low rpm. This has a tendency to fire overly rich idle mixtures and normally smooths out the idle. At high rpms the msd only fires once but the box sharpens the signal to the coil giving consistant spark even above the normal 4000 to 4500 rpm range. The resistor in the ignition has a normal 3 volt drop. In start position the starter solenoid sends 12 volts to the coil to boost the spark. Look at the solenoid and you will see 2 small leads. One is marked S for start. The other is marked I for ignition. This is the 12 volt bypass lead. When you let go of the key back to the run position the voltage will go back to approx. 9 volts. Ford coils are made to run this way. It also minimizes point burn. Hope this is usefull!
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