I originally had the Mallory Unilite distributor with a Mallory Hyfire 6a ignition box. The problem was that after 10 minutes run time, the car would just shut off and not restart for 2 minutes. After that initial stall and restart, it would consistently run 1 minute and then stall and not restart for i minute. I rechecked all of my wiring, no problems found. What was happening was I was losing my tach signal out of the Mallory box. One minute after stall, my tach out of the box would read 0 rpm and then slowly increase to 400 and the car would start. I then found that I only had 5.9v to my ballast resistor, and 5.2v at the coil positive. Since Mallory is gone, I purchased a MSD 6a box and my troubles are gone. I decided to check my voltage out of the box to my ballast resistor and it's only 4.9v. Is this normal voltage out of a MSD ignition box? It seams low to me, I thought you needed 9.6v at the coil positive. If this is normal voltage, I guess that I don't need a ballast resistor to the coil. I haven't had this car on the road yet and I want to make sure that this is correct before getting stranded. Thanks
If you have an MSD 6A box, all the original coil + wire does is turn the box on. That wire would be connected to the thin red wire of the box. The box has two wires that go to the coil, an orange, and a black. The box actually applies 450 volts to the coil when triggered. I'd say as long as the box is turning on, you are fine.
I also run a Mallory Unilite with an MSD-6AL. If the original coil wire is a resistor wire than it is not supplying 12v to the MSD box. What I did was use the original coil wire to trigger a relay that feeds a full 12v to the MSD box. Actually the relay feeds a separate 6 circuit fuse box that I use to supply 12v while cranking to the MSD box, distributor, Holley ECU, elect fuel pump (via the ECU), or any other item that needs 12v while engine is cranking.
Or, you could just replace the resistance wire, http://www.v8buick.com/showthread.p...nd-HEI-System-function-tests-and-modification The OP has not said his ignition isn't working. His setup is currently turning the MSD box on then.
