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 MSD 7al problem 
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Joined: Sat Mar 16, 2013 7:58 am
Posts: 76
I have hurt 3 7al boxes in the last two months. A new -2 plus, a 18 month old -3, And my 20 yr old spare -2. All have the same problem. Bad idle, will not rev over 8000 rpm (gets worse as the day goes on), No power ( lazy off the line). They will run fine for two weeks then, act up. At the track today I replaced the coil and crank trigger pick up. Still have the problem. The new -2 plus is on the way to MSD to have it checked out. The -3 will go to TechWest. IS there some I should look for a problem? Am I missing something? Bob J


Sat Sep 05, 2015 8:47 pm
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Joined: Fri Feb 08, 2013 5:50 pm
Posts: 2305
Bad power connections are common, both the main ground and power wires. And I have heard a bad battery may be an issue, if the plates move around com vibration on the track.


Sun Sep 06, 2015 4:41 pm
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Joined: Sat Mar 16, 2013 7:58 am
Posts: 76
Mark,

The battery is new this year. Red top Optima. Was checking wires today,could not find anything that was not normal. Bob J


Sun Sep 06, 2015 6:29 pm
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Joined: Fri Feb 08, 2013 2:37 pm
Posts: 1704
Try another battery. A few years ago a red top optima acted like a 6000 RPM rev limiter, MSD 6al's (three different 6al's), carbs, alternator, torque converter, etc, damn optima. Lucky the guy who owned the car owns the dyno too.


Sun Sep 06, 2015 8:49 pm
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Joined: Sat Mar 16, 2013 7:58 am
Posts: 76
7al-2 plus box checked out OK. Got the call today from MSD. But, I did find that my distributor was not in phase. It was advanced. Timing was OK because I have a crank trigger. I did try a different battery, but it was before I checked the distributor. Jesel front drive. Will go racing next weekend. Bob J


Thu Sep 17, 2015 6:25 pm
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Joined: Thu Mar 28, 2013 6:09 am
Posts: 726
Bob a good read from John's forum here..
http://www.dragstuff.com/techarticles/m ... setup.html


Fri Sep 18, 2015 7:57 am
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Joined: Sat Mar 16, 2013 7:58 am
Posts: 76
Barry,
Last year when the engine was put back together, I asked to see if the shop phased in the rotor. Was told not to worry because it was done right. With the Jesel front drive there is not must adjustment to get it perfect. The only reason I checked the rotor was to see if something was broken. I had the engine up on 34 degrees BTDC. I noticed something did not look right. The rotor was almost half way between number 1 and number 8. ( 30 degrees advanced). No idea how it advanced itself or it was never right. Was kind of a pain in the back side to get it right. Remove water pump. Then remove distributor. Move rotor and reinstall all the parts. Some things on the front of my engine are a little close together. ( vacume pump and alternator). Now it idles better. Next weekend I will see how it runs. Bob J


Fri Sep 18, 2015 7:39 pm
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Joined: Sat Mar 16, 2013 7:58 am
Posts: 76
Ran on Sunday. 4.88@ 140.8 mph. That was the best run. Three other passes were close to that one. Runs good now! I will keep an eye on the rotor to make sure it stays in phase with the crank trigger. Bob J


Tue Sep 29, 2015 7:48 pm
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