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Master Dipstick
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Discussion Starter #1
I just replaced my ignition module for the 4th time in about 18 months. 350 crate motor MSD Street Fire HEI distributor. The first few times it caught me in a parking lot Monday evening I pulled away from a red light and it died. (luckily I coasted off the busy road into somebody's driveway) since I have been thru this before I checked for spark and of coarse there was none. My son came and got me, bought a new module and it fired right up. I understand that heat kills these things but 4 in that short amount time? I have owned a 69 Camaro ( put an HEI dist in it) and a 79 Camaro with an HEI and never had this problem. (I am putting the di-electric grease under each one each time.) Any ideas or is this really that common?
 

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you are not supposed to use dialectic grease, you are suposed to use heatsink grease, go to radio shack and buy some designed for processors, they have it there as heatsink grease or there is arctic silver some of the best stuff..
 
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Dialectic grease is whats killing them. Heat sink is what you need.
 

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Master Dipstick
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Discussion Starter #6
Not sure what is in the little packet that comes with the moodule, I thought it was dialectric grease either way I'll get some het sink compound and apply that. A call to MSD won't hurt either. Thanks
 

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Master Dipstick
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Discussion Starter #7
Just talked to MSD Tech Support they said to tap into the ground wire on the harness going to the cap ( middle black wire) and run it to the firewall or a known good ground close to the distributor. Existing ground is probably insufficient since the I'm running and aluminum intake manifold.
 

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Just talked to MSD Tech Support they said to tap into the ground wire on the harness going to the cap ( middle black wire) and run it to the firewall or a known good ground close to the distributor. Existing ground is probably insufficient since the I'm running and aluminum intake manifold.
Cool. If you dont already, run a ground wire from your engine block to your chassis and then ground that black distributor wire to your engine block. I've never liked grounding things to the body because our cars have rubber body mounts and the battery is grounded to the chassis, not the body.
 

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Just talked to MSD Tech Support they said to tap into the ground wire on the harness going to the cap ( middle black wire) and run it to the firewall or a known good ground close to the distributor. Existing ground is probably insufficient since the I'm running and aluminum intake manifold.
Your ground may not be adequate, but it won't be because of an aluminum manifold. Aluminum is a better electrical conductor than cast iron. Either way, go ahead and add a ground connection.

While you're at it, you should check all the main grounds. You should have the negative battery cable connected to the engine somewhere. Some connect to the alternator bracket, some to the engine block, and some to an exhaust manifold bolt. Be sure to scrape off any paint where the wires are connected.

Next, the battery negative should connect to the frame with a fairly large wire (#12 or bigger). The bigger, the better.

Third, the engine should have a braided ground strap from the block to the firewall.

If you have all these, you may not need the extra ground for the distributor, but go ahead and add it anyway.

Jack
 

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Master Dipstick
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Discussion Starter #10
Thanks for the input Jack I do have all the grounds you mentioned. The negative cable is grounded directly to the block down below the alternator, plus the large black wire from the neg. post to the fender and at least two braided ground straps from the block one to the frame and one to the firewall. I'll make sure all the paint is gone from where they connect and add the ground from the dist. to the block. (good point on the rubber body mounts)
 

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something is kiling them .i always use the white heat sink compound.make sure you ohm everything to make sure you have no grounds or opens especially in the pick up coil. check from the ground link inside the cap to ground as well.4 in a row something is up somewhere. have you had the failed ones tested ? are you useing quality parts ? a faulty coil will kill the module. if i have 2 fail in a row i replace everything inside the dist. coil ,capaciter,harness and pick up coil.
 

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VINTAGE MOTORHEAD
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MSD is super when it comes to failures and tech support. I also run a full MSD ignition. I am wondering if you need to upgrade from a chinese module to a MSD unit because of the intensity of the system? ?
Also..no electric welding on car eithout first removing ig box. All grounds must be ample.
 
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I was gonna mention that your prob having a ground issue. I have seen them with bad mounts or crappy ground straps but MSD set ya up..
 
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