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The strange MSD problem....solved! Long, but not terribly
https://slantsix.org/forum/viewtopic.php?t=27864		 Page 1 of 1
Author:  rock [ Sun Mar 16, 2008 8:32 am ]
Post subject:  The strange MSD problem....solved! Long, but not terribly
Hello all,

Matt C, 'Zilla and Dank replied with great thinking to a problem I reported in http://slantsix.org/forum/viewtopic.php?t=27730

Well, FINALLY there is a solution and it is not in the solution set of what we commonly encounter. I want y'all to know of a wierd ignition problem that CAN happen in MSD systems as it did to me if you use a Blaster 2 coil.

Basically, upon installing a new MSD 6A box, 8920 tach adapter (because of Sunpro tach) and a ebay item MSD Blaster 2 coil, things worked GREAT, for all of about 3 to 5 minutes. Then it was if you turned off fuel with a petcock...loss of power, smooth extinction of ignition, rolling to a stop at roadside. Hop out, check wires and such, turn key, runs fine, then repeat stop. Because I have a dual system wired in I just popped in another Mopar electronic dizzy that I connected to another coil and to the GM HEI unit and cruised on home.

Now to the interesting solution: It seemed likely that the MSD 6A box got too hot...well it isn't so! And in fact it now seems that if your MSD system has what you think is an overheat problem, it may well NOT be so. Not only does MSD tell you that, once I found my problem I mounted the MSD box on valve cover above Dutras to be sure I could get it hot with no problem and had none. Byran Zublin's "Reverse Engineered" report on the MSD6A suggests to me the MSD is a different system from HEI and the Mopar electronic...but for me the proof was the box on my valve cover.

To start my troubleshooting I first covered the MSD box with an ice bag for 15 mins then fired up the engine parked overnight....and it quit running after 3 minutes. So much for an overheated MSD box, but maybe still in the MSD box?

Connect box to a stock Mopar coil and run errands all over town...NOT the box. Check resistance on two Mopar coils, one MSD solid state coil , and the Blaster. In each case the primary and secondary resistances were at spec. Connect coils one at a time to the GM HEI and then to the MSD 6A...all work fine, including the Blaster coil on the HEI...BUT NOT ON THE MSD 6A box. WHY?

I had a bad Blaster 2 coil...probably why it was dumped on ebay...bad in the sense it cannot saturate properly from the capacitive discharge unit but can saturate from other ignition systems. I confirmed this possibility with MSD who have heard of this failure before. That same coil will work great with the GM HEI and with a resistor system....(anybody want it for postage?!!)

So the moral is even though your resistances are correct in all your coils, don't assume your MSD box is "overheated"...to the contrary it probably isn't, but your Blaster 2 can be internally damaged and still "work" with other systems and have "corrrect" resistance. Swap in a old Mopar coil first to separate MSD 6A box from coil problem. I am now running the solid state coil cause it fits so well physically in my application, and using the MSD 6A box I started with.

rock
'64d100
Author:  SlantSixDan [ Sun Mar 16, 2008 8:51 am ]
Post subject: 
Great detective work!
Author:  argentina-slantsixer [ Sun Mar 16, 2008 9:13 am ]
Post subject: 
IIRC there's 2 types of BlasterII coils. (and not just the exterior thing, one being red and the other being chrome) There's a difference in applications. I think there's a blaster II coil just fo rcapacitive discharge and other for any other system. It doesn't make sense to me (as in why they would produce a coil that's not for their ignition sys) but...

I'll log in my MSD forums account right now and ask for confirmation on this thing, I'm not 100% sure if I'm recalling this correctly.
Author:  slantzilla [ Sun Mar 16, 2008 11:20 am ]
Post subject: 
If it came off of the Bag was it a real MSD coil and not a knock-off? Good job tracking it down. :D :D

I had the same kind of issue with a Mopar electronic kit on my red car. Chased it for a while and it turned out to be the coil. Car went through a coil a year early on. I have a Blaster II on it now that has been there for at least 5 years. :D
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