MSD ?

Old 03-17-2008, 12:05 PM
  #1  
hammertime
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I tried starting my car this past weekend. It was cold (mid 30's) so I figured it was just cold blooded. I tried several times and it just acts like the timing is way off. Motor is bucking back, and volt gauge is just lugging down (to 8-9 volts) like it terrible far off and having a hard time cranking.
I hooked it upto the dist. from the dyno that is set at 37 degrees so I figured it'd be very close. I checked #1 plug and it was close, but still had no luck at all. In fact it started bucking so hard it broke the starter and some teeth on the new fly wheel are ground down a bit now. When cranking the car without ignition on its fine on the volt gauge.

I changed the wiring in the car over the winter and confident in it. Same Coil, New Plug Wires, same plugs from dyno, new 7al3 box, new k&r switch panel. Good grounds and power to everything.

My question is the msd 7al3 start retard is taking 25 degrees out could this be taking so much out that cylinders are firing so fast right after each other it could make the motor buck back on me ?
I dont have all the msd chips in the box this shouldnt affect anything should it ?
It just seems advanced so far its doing it and I wouldnt think being so retarted would do this ?

thanks for the info
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Old 03-17-2008, 03:10 PM
  #2  
fishman1
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I think your msd box on the start retard is neutral so the retard doesn't come in to affect until u r at 1400 rpm then it will retard .....that is how mine works anyways a little diffrent then yours as i have a 6al with a retard box seperate ..........
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Old 03-17-2008, 03:43 PM
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hammertime
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Originally Posted by fishman1
I think your msd box on the start retard is neutral so the retard doesn't come in to affect until u r at 1400 rpm then it will retard .....that is how mine works anyways a little diffrent then yours as i have a 6al with a retard box seperate ..........

I thought maybe the samething, this is straight from 7AL3 instructions for start retard.

The retard will be deactivated when the engine reaches about 1,300 rpm and will not occur again until the ignition is turned Off.
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Old 03-17-2008, 04:04 PM
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johnracer
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Hey David, check the rotor phasing. I had the same problem on my small block when I went to the 7al3. The timing was fine but the rotor phasing was off far enough that when the start retard was activated, it would fire on the wrong post. It actually started better if I got it cranking, then hit the ignition. Once I got the rotor phased correctly, it worked great. Just a thought...
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Old 03-17-2008, 04:09 PM
  #5  
johnracer
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I thought of something else, if you don't put the zero chips in the other retard sockets or have the terminals grounded, those retards will activate. I'm not sure how far they go with no chip.
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Old 03-19-2008, 01:17 PM
  #6  
ron19
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I've never had good luck starting a cold engine that has a bunch of retard in the timing. I had a good 12.5:1 406 that I always had problems starting when it was cold. Had the MSD billet with the weights installed so that it was retarded (on a curve) from start up till 3000 or so rpm. Finally (after a starter and couple ring gears) I took the distributor out and locked down the timing at 36 degrees all the time, never had a starting problem again. Just recently, I fired up my Uncle's BBC 427, 13:1, badazz motor and he had his electronic ignition set with retard at start. Would fire for crap, took retard out and fired right up. That's how I run mine now.

Hope this helps.
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Old 03-19-2008, 02:08 PM
  #7  
Tod74
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Originally Posted by johnracer
Hey David, check the rotor phasing. I had the same problem on my small block when I went to the 7al3. The timing was fine but the rotor phasing was off far enough that when the start retard was activated, it would fire on the wrong post. Once I got the rotor phased correctly, it worked great. Just a thought...
Yep
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Old 03-19-2008, 07:47 PM
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rob41willys
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I tried using the start retard on my 7AL3 with the dist. locked at 38deg. Didn't like to start at all. removed the start retard and starts fine
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Old 03-20-2008, 02:21 AM
  #9  
hammertime
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Originally Posted by rob41willys
I tried using the start retard on my 7AL3 with the dist. locked at 38deg. Didn't like to start at all. removed the start retard and starts fine
This is what I am going to do, several others and msd all suggested this. It seems the 25 degrees out wasnt one of the best ideas msd had. 10 would be fine but 25 is to much for a bigger motor. thanks again for all the answers !
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Old 03-21-2008, 04:56 AM
  #10  
billhendren
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Sounds like the polarity is backward from what was run on the dyno.unplug the dist or crank trigger and take two short wires and plug them into the dist or crank trigger and x them before plugging them into the loom. if the engine now starts re wire the pickup in that position. if your using an analog box the correct polarity is the most retarded position.if your using a digital its the most advanced position.Bill
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