Fella's, I've just installed a pertronix Ignitor1 electronic ignition and flamethrower coil. My car is a 1971 200 automatic. Engine starts more quickly and definately runs/idles more smoothly. :bananaman I'm wondering if I can/should open up the plug gap? I've only had the car running for a short time, so I'm not sure how good this engine can get. Anyone with personal experiance with these parts on this engine?
I have a pertronix, and you can open the plugs up to .045, and it will run better and get better mileage. The pertronix, with a good hot coil, put a lot more voltage to the plug, so you can increase from .035 to .045. Good luck, Earl
The more you open the gap, the more voltage is required to jump that gap. The extra voltage destroys wires and contrary to popular thought it does not increase the ability to ignite the fuel-air mixture. The coil will produce a certain amount of power (watts) with each spark. That watts is figured by multiplying the the voltage and amperage. Amperage is what gives the spark its heat not the voltage. The wider gap takes amperage away from the spark because it causes the voltage to rise. For this reason I keep the spark gap as narrow as I can and keep the engine running smooth. For the V8 SBF's and my experience that minimum gap is between .026 and .030 (most of the time it runs .028 for me and my style of driving) If I drive harder the engine likes a smaller gap - like at full throttle - but at an idle it will skip once in a while. What will determin you gap is what it will idle smoothly at. It will also make your plugs last longer, give better gas milage and make your engine run better.
I gap mine at .040-.045 . No problems. The plugs on my V8 Ranger are two years old. Daily driven the whole time.
I have heard what PaulS is talking about. Of course, I never do anything the right way, and have run mine at .045 since I put in the pertronix, about 4 years, 4000 miles ago. Runs really good, and more importantly, starts RIGHT up now. I upgraded my coil to the next one better than stock (Accel Super Stock, just a bit more juice, but still a weak coil).
Thanks for the input guys. Like I said I have installed a flamethrower (40K V) coil with the Igniter ignition. It was the coil upgrade that I thought would allow for opening up the gap. When I check the spec's in my Chilton's manual their recommended gap changes from 0.032-0.036 (points ignition) to 0.044 when the car changed over to Duraspark in 1975. Haven't I just made essentially the same chage to my car? Thanks again for the feedback
Yea, more voltage allows a wider gap. When I did the first une up on my 95 E150's 351W, the gaps had widened to .075-.080 and they were still doing the job.
There is a lot of education needed on ignition system performance to be correct in these answers. The original spec is based on the old points and coil system that had limitations in output. Basicly the gap can be opened until the cylinder experiences missfire with the coil and drive system used. Too small a gap will make the idle rough. Mention was made about the power in the gap at fire time. These systems are less than 1% conversion efficient. Look at coil input power. 12 v x about 5amps +/- = 60 watts but this amount never shows up in the spark gap even with reasonable losses included. The mixture determins the voltage breakover needed each time and is never exactly the same each time. The coil and drive system has to have reserve to be able to fire the plug under the worst condition each time or a missfire occurrs. This means the plug gap needs to be large enough to allow easy ignition, still have voltage reserve to fire the leanest mixes and have reasonable life due to errosion and contamination before missfire becomes an issue from normal wear. There is a lot to the science that needs to be included in a general discussion or myths begin to be circulated. I'm not very well accepted on this board for having been here since the mid 90s but I will continue to express what the technical natures are for these subjects, no matter because I know it all to well. Anyone want to debate the technical points bring it on. Since I am met to often with cocky answers, I might as well be cocky also. The last guy who thought he know about ignition systems got shot down. Whos next? Yes I have an attitude but but some on this board have brought it on by being cocky with there answers and stupidity so you get some of it back to enjoy.
Tell us more, I find this all interesting. I would never have thought that the gap on the plugs could be increased, I myself just bought new plugs, a Flame Thrower coil & wires, to go with my Igniter that I installed last year. I was in the middle of trying to figure out what gap I should be using, since I switched to E7TE heads and they use a different plug than the factory 1973 heads did.
Im' going out the door right now , so will get back to you about this as long as you will be open to the reasons and needs of ignition systems. I'm not here to argue but I get feedup with the ignorence shown then these people try to defend it yet!
I know nothing about anything, so I don't argue with anyone. Everyone has a difference of opinion, so sometimes you just have to deal with it, and not let it bother you.
Great info. It's good to hear the detail that goes into making up these specifications. Sometimes the answers are not as conveinent as we'd like them to be. But I do appreciate a well written, and thought out answer to someone's gut feel. I know that I have a tendency to "dumb down" a topic until it fits the amount of time I have or attention I choose to devote to it. Human nature I guess. Thanks again for the info.
The 60 watts (12volts x 5 amps) that go into the coil come out to 40000Volts at .0015 amp while assuming no losses. The losses are roughly five percent in a transformer so it is easy to see that the power in is equal to the power out. If you reduce the voltage REQUIREMENT to 20000 then you get .003 amps (again assuming no loss). That .003 amps will generate twice the heat for ignition as long as the gap is wide enough to ignite the air/fuel mixture. You should remember that the gaps were increased so the plug could fire an extremely lean mixture during the first decade of the smog engines. Those ignition systems also were designed to discharge capacitors across the coil with a 250 volt pulse of roughly twice the power of the old points type ignition. If you are using the Ignitor system without an external amplifier you are actually using a points system without points. The Pertronics system is basically interupting the voltage to the coil by pushing a positive voltage to the negative side of the coil. There is 12 volts to the coil all the time and the hall effect generator (distributor module) sends a very quick 25 to 50 volt surge to the negative side of the coil. That shuts the power flow through the coil off and causes the spark. The spark is essentially the same as with a set of points. If you are running the Pertronics system with a separate amplifier then you are probably running a capacitive discharge system and none of what I have said here applies to that kind of system. The CD systems produce higher voltages much faster and they are constant voltage devices rather than constant power divices like the points and Pertronics devices alone. Just remember that the wider gaps and higher power ignition systems were made to overcome the difficulties of igniting very lean air/fuel mixtures. We don't have to use lean mixtures so setting the gap as narrow as our engines allow will save on plug wires and ignition systems wear. I am not advocating that anyone change what they are happy with. I am trying to teach the inner workings of the different ignition systems and the reasons that Ford and other manufacturers used wider gaps in their engines. Not flaming you guys for running something that works for you. I would suggest that you have open minds to try something that you haven't to see if it works better. (unless you have tried it and decided it didn't work). It really doesn't matter one way or the other to me how you gap your plugs or tune your engine. I have no investment. I am a teacher by trade so I have a bad habbit of providing information when I see it is lacking. That is all I am attempting to do - provide information. Do with it as you will.
Paul, I think we have a lot in common. You see the same things I see on this board; a non willingness to look more deeply in to how things work and a tendency to defend ignorance. ********************************************************* As promised; starting at the plug gap, the space in the gap has a dielectric constant composed of the compressed air and gasious moleule mixture in suspension and moved by the sweril generated by piston movment.. The 'constant' this mixture presents determines the breakedown voltage required from the coil no matter how the coil is driven. The leaner the mixture the higher the voltage required, the larger the gap the higher the voltage required, the more leakage that exists the higher the voltage, the larger the rotor to cap gap the higher the voltage etc. When the ignition system runs out of reserve from any or a stack up of these conditions, a missfire occurs at any time but usually begins at the leanest mixture first and get wose unless an outright failure occurs. Going on the hot ignitions, there is indeed a point where the stock plug wires will not survive over the long term because the carbon centers distruct from the higher applied voltages and breakdown the carbon center path and even the insulation to the outside causing leakage or outright failure. The failures causes are exactly the same as the breakdown in the plug gap in that the molecules the insulation is composed of breaksdown such that electrons are pulled out of the materials molecular orbit and is the source of material distruction ( read pinholes, burn-thru etc). With hot ignitions, special upgraded wire with lower non-carbon center conductors are specified for these amplifier driven coils if long life and low leakage is as goal. All this info is in the mfger instruction and you won't see it in Jeg's or Summit catalogs. They sell parts and that's it! It's up to you to find out the needs afterward, unless you dig it out. There are a number of different ways ignition is generated, supplied to the coils and coils of different designs. Let's jump ahead a bit. We have come from a single coil non amplified system to voltage boosting coils to voltage boosting and higher output coils, to coil packs for 3,4,6,8,10 cylinder motors and now to coil over plug systems. Among the reasons why, have to do with the quest for cleaner burning, leaner burning motors and to meet federal emission standards. Advance to coil over plug systems. On an 8 cylinder motor, the coils are very small being wound in a ferrite circular cores in most instances. This reduces size, radio interference generation, faster core saturation time and more control over individual cylinder timing from the PCM (computer) that cannot be done with single coil systems. To come back to some of the questions; It make little differencne what plug design is used as long as it has about the right heat dissapation for the head and application. The spark required is somewhat influened by tip design for example a big tip as opposed to a small wire tip. The wire tip will fire at leaner mixtures assuming no other system changes. This is simply because the 'electric field' presented by the high voltage is much more consentrated at the small tip and is more dense a field. Remembering back to school that a positive field attracts negitive electrons so this is where the breakdown accross the gap occurs by attracting electrons out of the mixture that begins the 'kernal' for combustion. Carrying this further, the breakdown is an equivelent resistance (R) completing the coil circuit to ground. Develope further that once the breakover occurs, the coil voltage is at whatever value it needed to be with the rest (reserve) waisted by the short circuit at that instant. This suggest the quest for ever higher coil voltage will only be harder on all componants involved unless a demenstrated application shows the need to use higher voltages beyong the usual reserve levels. As stated before, the coil driving power is usually constant and may vary with rpm in the primay circuit but the secondary only uses what it needs with the rest waisted so the seconday power in never fully present accross the plug gap. How this occurs is the colapse of the coil saturation self induces the voltage used at the gap. The waisted energy is aborbed back into the coils core and back into the primary side because once generated it has to go somewhere and not just dissapear. It's not a matter of auto power dissapation adjustment since the gap resistance is still apart of the coil circuit and just dosn't stop at the gap. For those who may understand, it's the same in an RF transmission line. If all the energy is not absorbed by the load, a mismatch is indicated and reflects some power back to the source and is either lost or does damage, it's a (law). Note that sometimes this unused energy is the cause of coil insulation distruction, cap and rotor burning, leakage and on down the line. So it's not really a mistery when all is taken into account. Lastly, consider the rotor to cap post gap, then add the plug gap and you have well over .100" to fire accross. The difference is the rotor to gap distance is usually air for a dielectric constant mixed with oil vapors, moisture and argon gasses from the continious arcing inside the cap as the motor runs. This arc is quite hot in terms of temperature and is the errosion and metal melted beads you see on these parts after so many thousands of mile of use. Normally 7000 to 10,000 volts are all that is needed by the average motor for reliable ignition on street motors. Investing in the 40,000 volts and up 'hype' is a waist unless it's needed in an application proven to need.
I just know what worked for me. I increased the plug gap with my Pertronix, and I got more power, better gas mileage and a better idle quality. I do think the coil is the key in getting the ignition systems to work properly, and the Flame Thrower or, in my case, an Accel SuperCoil made for a good combination. I do thank you both for your insight into how these things work, and it is a very good lesson on ignition systems.
