Darryl, I measured 1.5 ohms between the + and - terminals on the new 12V Bosch H.E. coil, therefore, no internal resistor. Bill
Bill - I went on line to read MSDs instruction book. In addition, I telephoned MSD technical support and spoke with a human. The initial problem of Engine Run-On may be related to the following: "ENGINE RUN-ON If your engine continues to run even when the ignition is turned Off you are experiencing engine Run-On. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD receives power directly from the battery, it does not require much current to keep the unit energized. If you are experiencing run-on, it is due to a small amount of voltage going through the charging lamp indicator and feeding the small Red wire even if the key is turned off." "Most other applications: On other applications where engine Run-On is experienced, a Resistor can be put in-line to the MSD's small Red wire (Figure 7). This resistor will keep voltage from leaking through to the MSD unit." Paul (NC Mondial) was close in the 2nd response to your initial thread. It appears that MSD wants a large gauge conductor to the battery. The small, switched red wire simply activates the MSD unit, but most of the current used to power the MSD unit comes from the large red wire. Many external aftermarket audio car amplifiers work in the same way. They have a small switched conductor to the radio, with a large gauge supply to the battery. The technician at MSD was not an EE, but I could interpret some of how the MSD is designed (proprietary - he would not provide the schematic of the device). Bottom line - the technician stated that there is no problem in switching the large red wire and the small red wire. Just make sure that you use sufficient gauge wire for 1-amp per 1000 RPM (7 amps for a Dino). Second, a ballast resistor is not necessary if you hook the MSD to your points. His thoughts about a ballast resistor are consistent with my earlier post, which is more technical. His interpretation is that the ballast resistor simply reduces the current flowing through the points, thereby minimizing spark and point errosion. If using the MSD with points, the MSD passes minimal current through the points, hence a ballast resistor is not needed. I suspect that the same is true for a Dinoplex-Permatune box. Have fun. Jim S.
Adding ethanol to gasoline increases the octane number - a measure of the fuel's resistance to pre-ignition or engine "knock." As well, ethanol contains oxygen, which allows for cleaner and more complete combustion. So if you are getting better performance with higher octane, your car LIKES the ethanol. There is more ethanol in the high octane gas. Birdman
Hmm . . . Jim, I think you missed my post #16 and yesterday at 11:49pm, where I say I've solved the Engine Run-On problem. Also, I'm working with a new Dinoplex (see the latter post for the wiring diagram), not an MSD. I took out the 26 year old MSD in reaction to the initial problem which was an ignition failure on a Sat afternoon fun drive. Put in the Dinoplex which ran pretty good except I couldn't turn the engine off and it was very hard to start Hot. It's been a l-o-o-ong and complex thread so I understand the lapse. In any case, we are now discussing whether or not the ballast resistor could be the problem with this set-up, like, e.g., it shouldn't be there at all considering that I've got a new 12V H.E. Bosch coil that was part of the Dinoplex kit from Superformance. Please check out that wiring diagram and the last dozen posts and give your much valued and respected opinion. Bill
Very interesting. I didn't know that ethanol increased octane . . . thought it was other additives. In Virginia our summer blend is "up to 10%" ethanol. Does that mean if we went to "up to 20%" we'd get even higher octane ratings without too much additional cost? Is ethanol more or less expensive to process than oil based gas. I'm a dummy on this subject. Maybe you could start a new thread on this subject. Thanks for the info, Birdman.
Dignini - I have a Crane optical system as well. Put it in a few weeks ago. Works great!!!! I feed an MSD with the Crane. Bill - yes, I have read each entry carefully...from the beginning. I know that you have fixed the run-on problem, and you did so by switching the power to the Dinoplex rather than have it continuously connected to the battery. Bravo!!! The new problem is the hot start difficulty. Lose the ballast resistor. It should not be necessary, but is unlikely the culprit. Could spark plug gap be incorrect??? Jim S.
Jim, I'll check the gap tonight. As I remember, they are set at .035. I'll check grounds, ditch the resistor and go directly to the + post on the coil. That will double the voltage to the plugs which should help. Weather is supposed to be crappy for a couple days so my test drive won't be till late Sat or Sunday A.M. (it's also my wife's birthday weekend so I have to be extra nice Bill
The capacitor (condensor) in the distributor body is the electrical component that reduces current (spark) across the points and increases the points' life. Increasing the resistance in the coil primary circuit via an internal or external resistor will decrease the amount of current flowing through the coil. It's simply Ohm's law: V= I x R. However, this also reduces the high voltage output of the coil.
The 3000 me thinks. I'm also watching this thread to see what develops http://www.ferrarichat.com/forum/showthread.php?t=108953
"Does the MSD have advantages over the crane 700 or 3000/?" Dignini - none that I am aware of. I had purchased the MSD prior to removing my points and replacing with Crane's optical system. I telephoned Crane at the time and they said that the Crane system is compatible with any capacitive discharge system, specifically including MSD. Jim S.
Has anyone confirmed that the MSD system in fact provides multiple sparks to the same spark plug? The coil needs time to store energy in the form of a magnetic field before it releases it. The energy equation is 1/2(L)X(I)X(I). That's one-half times the inductance times the total current squared. BTW, the current flowing through the primary circuit of the coil happens when the points are closed, thus bypassing the condensor. When the points open, the current is shut off (except for a minute amout flowing into the condensor to minimize current arcing across the points gap) the magnetic field collapses. The energy, (volts times current squared) is sent to the spark plug. In a 12 volt coil at one amp that produces, say, 48,000 volts; that would be 4,000 joules. The little condensor in the distributor is too small to store that kind of energy and would short out if it were part of a ringing circuit.
How would it apply to an optical pick up system and no condensor. Anyway what advantage would multiple sparks have over one nice big spark correctly timed? Is it not the first spark that does the damage and the others go along for the ride?
The literature says that at high rpm the system provides only one spark. I suspect that the capacitor discharges its energy to the coil very quickly. The energy stored in the capacitor is "one half the capacitance times the voltage squared"; 1/2 x C x V x V. If the voltage discharged to the coil is high (about 480v) and the duration of this current is short, the result is the coil will produce a strong spark without burning up. Assuming that the resultant spark is 48,000 volts, I calculate: 1/2 x C x V x V = 1/2 x L x I x I (where C is capacitance of the CDI device and L is inductance of the coil). The coil normally will boost 12 volts to 48,000 volts; thats a factor of 4000. However, in a very short duration of 480 volts, to get 48,000 volts you need only a boost factor of 100. The literature says the duration of the capacitor discharge is one millisecond. What's happening is the primary circuit in the coil is receiving a high voltage for a very short time before the circuit is opened. This is only enough time for the coil to boost the voltage 100 times and not overheat.
Accomplished all items above today. Gaps were at .035. The plugs show that the front bank (4,5,6) is running leaner than rear bank for some reason. Haven't seen that before. Decided, since the plugs were out, to go with a new set of NGK BP7ES which is what I've used on road and track for years . . . set to .035. Car started cold AND HOT beautifully and ran smoothly and with good power at all rpms. At the end of my test drive I checked the air flow into each carb throat and all were evenly balanced at idle. Could be I've got a vacuum hose leak on that front bank. I'll check it. Anyone have ideas on what else could cause the leaness on just the front bank? MANY THANKS to all for the advice on the ballast resistor with the new Dinoplex. That was definitely the culprit on the hot start problem and doesn't make sense for overall performance. Not sure why Superformance has that in series with the 12V coil they supply with the Dinoplex. They also need to show the power source coming from the ignition switch so dummies like me don't automatically mimic the MSD set-up. Dino now sounds and feels great! Bill
Bill - An air leak on one bank will certainly impact operation and mixture. Those tiny hoses coming off of the intake manifold are difficult to find, but they must be sealed either as designed...terminating in the plenum or shut with a clamp and small screw inserted. Otherwise, a careful quarter turn of the mixture screws, one at a time (outward) may help. I turn 1/4 turn, one at a time, while listening for the idle to rise. When the cylinder is firing correctly you will notice a rise in idle, and then a slowing of idle RPM as you continue to the point of too rich. By counting your turns you can always get back to where you started. Give it a try. Jim S.
Although I don't own a Ferrari, I want to tell all of you how much I enjoy communicating with all of you. Thanks Jim for introducing me to your internet friends. I just hope congressman Foley doesn't own a Ferrari.
Jim & Dignini I use just about the same technique, Jim, and occasionally I'll breakout the Colortune and set the mixtures to that lovingly bunsen blue color. You all have convinced me that I can't live without a Crane 700 inside the distributor. So I think I'll do that conversion, do the colortune thing, re-balance flow and check the teeny-weeny vacuum hoses and the brake booster hose. Dig, all three front cylinders (4,5,6) were uniformly a lighter brown (light but not burned) then the rear cylinders which were a bit on the dark brown side. As I was falling asleep last night, it hit me that: 1) this is not necessarily an idle adjustment problem but rather a running at speed problem, 2) could be the rear bank is running too rich (dark brown) and the fronts are okay, 3) I haven't touched the normal jets on these carbs since I did a carb rebuild in about 1992, therefore, it's probably not the jetting, and 4) I did mess with all the mixture adjustment screws several months ago trying to minimize popping on deceleration. The latter is possibly ONE of the causes for what I'm seeing on these plugs. The other, vacuum leaks, can cause serious problems if unattended. Shall we start a separate thread on this? How do I do that without losing the last few posts? Bill
