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 13 2010, 04:51 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 |
Okay, partial success!!!
We got out of a training class way early today, so I cam home, rewired my ignition, and collected some more data. First off, OMFG! That rewire changed the cars starting habits like you would not believe! The "pump the gas twice, crank for 20 seconds until it fires while playing with the throttle" was gone. I started my usual routine and the engine caught so fast I turned off the car in surprise! If the engine stalled I could restart it by just reaching in the window and turning the key. I could almost never do that before. I suspect this will be a major change for the best. But, it still idled crapily and would sputter and die unless I gave it more gas. You can hear the misfires. So I got out my timing light to check spark on the different leads. I held the timing light on each lead for ~ a minute and just watched the flashes while the engine idled. My idle for tonight's experiment was set ~1000 rpm. Plug wire 1 was a metronome. It never skipped a beat that I saw. Plug 2, 3, and 4 all had seemingly random misfire events. When the engine would sputter you could see that it was not getting spark on that cycle. Most of the time they would fire, but sometimes they simply would not. However, when I added even just a little more gas, the misfires seemed to go away. Its like the timing got noticeably better around 1400-1600 RPM. The plugs are new - under 1 hour run time on them. The MSD spiral wound wires are ~1.5 years old - but the fact that the spark gets better as the engine starts to advance leas me to believe that the issue may be with the Mallory's initial timing set before it starts its mechanical advance. I did not check where it was timing in at idle. If I can get time again tonight I will run out and check that. Any ideas? Zach |
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