I have a mallory dist converted to breakerless and want to replace the stock coil i had to use with the accel 8140 that was in there before it died do i use the ballast resistor that's in there now and was with the accel coil. or by pass it chris
What is the voltage in the coil wire with key on and no ballast resistor in place? I ask because if your original wire harness is unmodified, there is already resistance built in to the coil +12V feed wire. If you're not sure if the original resistance wire was removed or not, check with a voltmeter and report back. The next step will be for you to tell us exactly which Mallory and other aftermarket parts you're running. If you don't have the original instructions for the breakerless setup (which will tell you about using a resistor or not), we'll see if we can find them on the web. We need to know what to search for first; part numbers, etc. The more detail you provide the better the chances of getting good advice. Devon
Mallory dist. part # 4764301H with 2092m cap and rotor Mallory 6100M High Performance E-Spark Replacement Module Mallory 29351 High Performance Active Power Filter Mallory 700 High Performance Ballast Resistor Mallory 938 8mm wire kit Bosch platinum plus 4009 plug http://www.taperformance.com/proddetail.asp?prod=TA_1235P (carb and intake setup thatcame on the car when i bought it) 1975 350 head ID 1248452 F/30 key in on position 11 volts to coil with ballast unplugged 5 volts to coil with ballast plugged in let me know if you need anymore info
Good info. First of all, the Mallory Unilite Distributor must have a resistor in place, either the factory resistance wire, or a +12V source plus ballast. See http://prestoliteperformance.com/Po..._wiring_diagram_test_procedure_1214M_0000.pdf What's puzzling is that you tested +11V on the existing wire, which is lower than battery voltage, but not as low as I was expecting with a factory resistance wire. If you run the separate ballast resistor, it's going to want to see full battery voltage, so you need to check into that next. I'm assuming if you test the battery directly you're seeing over +12V, no? Anyone got a voltage reading they can share on a system with the factory resistance wire in place for comparison? I think the +5V seen here with the existing wire (whatever it is) plus ballast resistor means too much resistance, would like to confirm. Devon
I think 5V coil voltage (through a ballast resistor) is pretty reasonable. Remember, in dynamic operation, there is zero coil current when the points first close, and zero V drop across the ballast resistor, so the coil sees the full 14V or so. Only as the current builds up (storing energy for the next spark) does voltage drop across the ballast resistor build up. Eventually the maximum current levels out (at low or no rpm) at much reduced coil voltage. If the coil voltage DID NOT reduce a lot, current would just keep increasing & burn out the points, which the ballast is intended to prevent. Some electronic ignitions don't need a ballast, because they turn on coil current JUST IN TIME to reach desired maximum before spark, no current limiting needed. That is why, it is necessary to find out if THIS electronic ignition operates that way. Bruce Roe
I called Mallory tech support yesterday and was told that i did in fact need the ballast resistor with the current setup I have but Bruce and Devon could you look at this thread I started about an engine stumble and let me know what you think maybe the two threads are related Thanks Chris http://www.v8buick.com/showthread.php?240017-Engine-stumble-at-idle&highlight=
What you need to determine is if someone has replaced the resistance wire in the harness. If they have, you use the ballast resistor. If they haven't, you do not need a ballast resistor. The GM resistor wire does the same thing. As far as your other problem, I believe the problem is the carburetor. I had a Carter AFB on my 350 in a Skylark. I could never get it to transition cleanly into the secondaries. A CORRECTLY calibrated Q-jet is a much better carburetor. Once you have run one that is correctly calibrated for your engine, you will notice a big difference. You cannot tune the secondary air valve on the AFB design without grinding on the counterweight, and that is not reversible if you go too far. The AVS carburetor is better because you can adjust the air valve. You momentary dip at idle still sounds like an electrical connection to me. If the engine harness has been abortionized, get another harness and be done with it.
