Mallory ignition questions, Partial success! |
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Mallory ignition questions, Partial success! |
VaccaRabite |
Oct 10 2010, 05:59 PM
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#1
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En Garde! Group: Admin Posts: 13,584 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
My carbed 2056 uses a Mallory Unilite ignition. All summer long I have been fighting intermitant misses leading to the motor dieing at idle. After dicking with the carbs and adding fresh spark plugs, I am now moving to ignition.
So here is how my system is set up. Bosch blue coil. Mallory Unilite ignition. The ignition is behind a resistor block. MSD spiral wound plug wires. NKG b5es plugs pregapped (one heat range hotter then stock as suggested in the resent spark plug thread) . My tach is not dancing when I have a miss. The idle indicated drops as expected, no drama. So I don't think that the coil is grounding out or arcing. As I understand the Mallory dizzy, it either works or it does not work, and there is not a lot of in-between. My primary suspects are the plug wires. I am using the MSD spiral wound wires suggested for use with the Mallory, and I have only been using them this season. Since you are not supposed to use the regular plug wires with a Mallory (as they can somehow cause the optical unit to burn out) buying replacement wires on a hunch is kinda expensive. Am I chasing my tail with this? Also, I am using the stock gap. I think I am supposed to be able to use a wider gap with the Mallory, which will give better ignition. What kind of gap should I be shooting for? If it does turn out to be the plug wires as the problem area, should I go back to the stock heat range plugs, or stay with the hotter ranged plugs? Oh, and for the "go back to FI" crowd, my motor is using a cam that would cause D Jet to commit suicide. In this case, it is not an option. Zach |
VaccaRabite |
Oct 12 2010, 05:24 PM
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#2
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En Garde! Group: Admin Posts: 13,584 Joined: 15-December 03 From: Dallastown, PA Member No.: 1,435 Region Association: MidAtlantic Region |
Hey, someone check me here.
Using a meter for testing ohm resistance, I had it set to 200. Other options were 2K, 20K, 200K, and 2M. If I had the right choice for measuring ohm resistance, I may have found part of my issue. My coil is showing 3.4ohms resistance across the positive and negative contacts. The PO of this engine had the coil wired through the resistor block, and assuming that I needed to do the same, I did. This weekend I will rewire my ignition and see what happens. However, the resistor was only giving 1.1 ohms resistance also, so I may be using my tester improperly or the PO was using the wrong resistor in the first place. Also, that thread on STF seems to make a pretty good case for the Jacobs coils. Is there a reason why the blue coils are preferred here? It would seem that a higher power coil would be what you want for a hot rodded motor (even it it is mildly hot rodded compared to some folks here) so long as you don't overpower your plugs, wires and cap. Asking lots of questions, yeah... But learning a lot. Zach |
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