Pro mag 44 ignition issues/experiences

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by rb0804, Mar 11, 2018.

  1. rb0804

    rb0804 Member

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    I was searching around the site looking for some common fixes for Pro Mag 44 issues. Most threads were about not starting, no spark, not enough rpm, rotor phasing etc. The other threads were more like maybe a points box went bad or coil or crank trigger. Since most small teams don’t have the budget to carry a spare mag, points box, crank trigger, timing box (grid, 8973, Leahy, six shooter,etc) so I wanted to start this thread so we can share our experiences together.

    Let me start by saying that I like the Racepak inductive pickup because it’s rpm log shows everytime the coil fires. If there is a down spike on the rpm graph while using the inductive pickup, the coil didn’t fire for some reason. Primary causes would be crank trigger or coil. I have experienced both recently. The bad coil was breaking down under load and showed a down spike randomly but not all the time and not always continuous. I didn’t notice any ‘shooting ducks’ or raw fuel shooting out of the pipes under load. I figured it was a Racepak issue so tech support came over and they thought it was a mis-fire situation for whatever reason (bad plug, plug wires, coil etc). At the time I had written it off but around this time a blower belt issue began to develop, but the car still wasn’t running all that bad, we were running some career best numbers at that time. Since kicking the blower belt is such a mess and expensive we sent everything out to be tested. Turns out coil was breaking down under load.

    I also had an issue with down spikes on the RPM graph not as frequent as the above issue (only 2-3 times on the run), but I could visibly see raw fuel out of the pipes along with a slight performance disadvantage. This was the first time out with a new to them engine with the crank trigger already installed from the previous owner. This was also with a Racepak inductive pickup. Once we switched to a new crank trigger the RPM graph went back to normal and performance picked back up.

    So what have you experienced? Figure out a points box was bad? How about the magneto itself? What were the symptoms?
     
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  2. Mike Canter

    Mike Canter Top Dragster

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    Two things that hardly ever fail is the ProMag and the Grid. Seen lots of time that people say the Grid is bad but it wasn’t. It really helps to use the Grid Data Aquisition after a run that has problems. You can download the data and look at Ignition In which is the crank trigger input or the mag input if no crank trigger. Should have no gaps in the signal. Ignition Out is the output of the crank trigger and Grid processing going to the mag. Again should look like the Ignition In with no gaps. That crossover switch you use when starting the car can cause gaps in the Ignition In and look just like a bad crank trigger. Engine vibration cause the crossover switch contacts to bounce giving you a miss while going down the track. The MSD coils are really a weak point. They go bad or degrade and either go totally dead or they degrade and slow you down. You should always have a known good coil in your trailer for swapping to troubleshoot. The best thing is to buy the new design coil for the Promag from Fuel Injection Enterprises. (FIE) owned buy Spud Miller. The coil is oil filled vice epoxy and can be repaired if problems but I haven’t seen one fail yet. If you have had your ProMag hopped up by Bob Wyman at System One then you are going to have problems with the MSD coil and should go to the FIE coil for sure. Points Box just suck. You would think over all these years that it has been out there that MSD would have improved the reliability. At $700 a box it is a high failure item and you should always carry a known good spare. Ignition wires can really be a problem. All that high voltage running through them tears down the insulation over time and you cannot check that with a multimeter. According to MSD most ignition problems are bad ignition wires or a bad coil wire. That coil wire gets shot with high voltage eight times the amount of a single plug wire so they break down. If the coil can’t get the spark through the coil wire then that spark is going to try and go somewhere in the coil and can really damage the coil. You should change that coil wire a lot more than the plug wires.
     
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  3. rb0804

    rb0804 Member

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    Thanks for the reply Mike. Do you have a recommended schedule for changing the coil wires? What kind of symptoms would one expect from a bad points box? Does the timing creep? Does it go all wacky?

    I was reading some information about the points box and the heat that they generate. It seems that the run time should be limited to the 3-5 minute range. This leads me to my next question, what is the proper way to mount the points box? Should it be rubber mounted with air space in between? Should it be mounted directly to an aluminum plate to help dissipate some of this heat? How about a heat sink for the back of it? Should we be routing some air over to it via a naca duct?
     
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  4. Mike Canter

    Mike Canter Top Dragster

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    I have never seen a bad Points Box change timing because that function in the box is not there. Usually Points Box failure result in a failure to start, the car quitting going down track or a serious missing. I have never heard it being a heat problem and I always shock mount them with a ground wire to the box. The coil wire should be changed every two to three races.
     
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  5. jay70cuda

    jay70cuda Member

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    I had a coil start going away. Here’s the thing about a coil. It will start, idle, rev up like normal. But until it’s placed under a load that’s when it will short out. Seeming like ignition miss or cut out. Looking back after 8 failed runs. I noticed the car would burn your eyes like a nitro car idling. Should of been my give away answer. But I always assumed if it starts it’s working?!? Not the case. I would buy Lahee used coils and rotate out every year. Not anymore. I buy a new one every year and move my old one to the spare. I’ll never let that happen again. All the money we spend and then to lose a whole event from not having good used ignition parts. Never again...
     
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  6. Mike Canter

    Mike Canter Top Dragster

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  7. turbo69camaro

    turbo69camaro Member

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  8. bandit496

    bandit496 Member

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    So, is this the same coil that is used on the SuperMag+ or is it the same configuration/case with different insides? JW
     
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  9. Mike Canter

    Mike Canter Top Dragster

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    I couldn’t answer all that I understand it was built to handle the 44 Amos into the primary windings. Call aSpud Miller at ‭(541) 990-2485‬ and ask him
     
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  10. TOL

    TOL Active Member

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    What is the best way to actually measure, monitor, log, the actual spark advance lead on a per cylinder basis with a Racepack or equivalent? Not what is commanded, but what actually happens at the plug(s)?

    Thinking it would be useful to overlay the command signals with the actualized outputs. One without the other would be a bad recipe and a diagnostic aid.
     
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    Last edited: Mar 13, 2018
  11. Mike Canter

    Mike Canter Top Dragster

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    You would have to use the Leahy Electrimotion system or the RacePak system that add a pickup on the crankshaft that senses the change in timiming and records it on the data recorder,
     
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  12. rb0804

    rb0804 Member

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    If you have one cylinder misfiring the timing graph won’t pick it up in all cases. I just went back and looked at a run that I knew I had a crank trigger issue and let’s say of 5 down spikes 4 had no change in timing and 1 went to 0*. But watching the car it was “shooting ducks” at least out of the right side of the car randomly. Fact is even with data logging, it can be hard to spot an ignition issue in the works, sometimes a crew guy with a keen eye can be very helpful.

    If your Racepak is capable of logging timing that is probably your best option, we use the Leahy which sends a 0-5v signal over to the Pro 1, but it’s not entirely accurate.
     
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  13. Mike Canter

    Mike Canter Top Dragster

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    Something to add. If you have a miss on one cylinder other that a bad magnet on the crank trigger wheel (which will show up on the Grid data acquisition ) in pretty well can’t be anything else in the mag, Grid or crank trigger. It has to be something further along such as the mag cap, plug wire or plug. Other than the crank trigger wheel the system doesn’t know one cylinder from another and will miss on all cylinders. It treats them all the same
     
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