[Ignition]: Ate up another Accel supercoil.
Thread Starter
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
Yes.
Going to put the order in right now for their HEI module. I just wish I knew why this was happening. I went for months with the first Accel before putting hte MSD on. Hmm...
Going to put the order in right now for their HEI module. I just wish I knew why this was happening. I went for months with the first Accel before putting hte MSD on. Hmm...
Melting Slicks
Joined: Apr 2002
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From: down that one road next to that big tree
Re: Sheesh! (JD 90 383)
could be the reason msd heavly suggested there HEI to outboard adapter part & using a blaster 2 outboard coil, not sure but it's possible.
Thread Starter
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
:rolleyes: Hmm, was the computer actually a problem ?
Thread Starter
Team Owner
Joined: Mar 2000
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From: Boston, MA
I just sent this to MSD, hopefully they can shed some light. I wonder if my cap & rotor could be shot and causing a high 2ndary voltage trying to bridge a large gap.
To Whom It May Concern,
I recently installed your Digital 6+ system onto my 1987 Corvette which is a 7-pin HEI system. I used your GM HEI installation harness to make things quite easy to install.
Since installing the ignition box (which I absolutely love so far) I have managed to burn up two Accel HEI Supercoil units within 4 weeks. The first one was about 4 months old and was operating perfectly fine before installation of the MSD. About a week after installing the MSD box this one called it quits. When this one blew I replaced it with a brand new one that expired within 18 days. Have you heard of this happening before or is this just my perpetual black raincloud of luck circling overhead? I just noticed that MSD offers an HEI Coil part number 8225 now and was planning on ordering that, but is there a condition you may be aware of that is causing this or that I should look for? I and 3 other friends have gone over the wiring and everything appears fine and there is no evidence of shorting out anywhere.
The coil that has burned up twice is Accel part number 140005. I have attached a picture of the unit. It is getting a little frustrating at $60 a pop and now I'm carrying a spare in the car because it seems now "if", but "when" will it happen.
Distributor: Stock GM HEI with Large Cap and in Cap Coil
Pickup Coil: Stock GM
Ignition: MSD Digital 6+, p/n 6250
Wires: MSD 8.5mm Superconductor Wires, p/n 31459
Ignition Coil: Accel HEI Supercoil, p/n 140005
Cap/Rotor: Conrad, p/n DR2009G (cheapie from autozone bought in a pinch, has brass terminals)
Control Module: Wells, p/n DR124 (cheapie from autozone bought in a pinch)
Thank you for your time and assistance,
Brian Day
I recently installed your Digital 6+ system onto my 1987 Corvette which is a 7-pin HEI system. I used your GM HEI installation harness to make things quite easy to install.
Since installing the ignition box (which I absolutely love so far) I have managed to burn up two Accel HEI Supercoil units within 4 weeks. The first one was about 4 months old and was operating perfectly fine before installation of the MSD. About a week after installing the MSD box this one called it quits. When this one blew I replaced it with a brand new one that expired within 18 days. Have you heard of this happening before or is this just my perpetual black raincloud of luck circling overhead? I just noticed that MSD offers an HEI Coil part number 8225 now and was planning on ordering that, but is there a condition you may be aware of that is causing this or that I should look for? I and 3 other friends have gone over the wiring and everything appears fine and there is no evidence of shorting out anywhere.
The coil that has burned up twice is Accel part number 140005. I have attached a picture of the unit. It is getting a little frustrating at $60 a pop and now I'm carrying a spare in the car because it seems now "if", but "when" will it happen.
Distributor: Stock GM HEI with Large Cap and in Cap Coil
Pickup Coil: Stock GM
Ignition: MSD Digital 6+, p/n 6250
Wires: MSD 8.5mm Superconductor Wires, p/n 31459
Ignition Coil: Accel HEI Supercoil, p/n 140005
Cap/Rotor: Conrad, p/n DR2009G (cheapie from autozone bought in a pinch, has brass terminals)
Control Module: Wells, p/n DR124 (cheapie from autozone bought in a pinch)
Thank you for your time and assistance,
Brian Day
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Team Owner
Joined: Mar 2001
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From: Cincinnati, Oh USA
Re: [Ignition]: Ate up another Accel supercoil. (scorp508)
The Accel coil is designed to have a pulse of 12 v switched to its primary winding. The MSD circuitry charges a capacitor (have to guess, but probably to 150 v or more) and then connects this capacitor to discharge into the primary of the spark coil. This pulse exceeds the primary windings voltage and/or current rating and is the cause of failure. A spark coil designed for cd (capacitor discharge) service should be used with the MSD ignition.
Thread Starter
Team Owner
Joined: Mar 2000
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From: Boston, MA
Coming from an EE that makes me feel better. Any ideas why the Accel is designed in this manner?
Here are the Digital 6 stats......
Operating Voltage: 12-18 volts, neg. ground (Full voltage output down 7 volts supply)
Current Draw: 0.7 amp per 1,000 rpm (7.2 amp)
with 14V bat.@ 10,000 rpm
RPM Range: 12,500 rpm with 14.4 volt supply
Spark Duration: 20° crankshaft rotation thru 3,300 rpm
Spark Energy: 135 milliJoules per spark
Weight and Size: 3.7 lbs, 8.5"L x 4.5"W x 2.2"H
Voltage Output Max: Primary: 535 Volts delivered to coil
Secondary: 45,000 Volts (MSD HVC Coil)
Here are the Digital 6 stats......
Operating Voltage: 12-18 volts, neg. ground (Full voltage output down 7 volts supply)
Current Draw: 0.7 amp per 1,000 rpm (7.2 amp)
with 14V bat.@ 10,000 rpm
RPM Range: 12,500 rpm with 14.4 volt supply
Spark Duration: 20° crankshaft rotation thru 3,300 rpm
Spark Energy: 135 milliJoules per spark
Weight and Size: 3.7 lbs, 8.5"L x 4.5"W x 2.2"H
Voltage Output Max: Primary: 535 Volts delivered to coil
Secondary: 45,000 Volts (MSD HVC Coil)
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
Re: (scorp508)
The Accel coil is designed to work on the OEM ignition which is a transistor that switches a pulse of 12 volts to the primary of the spark coil for each spark. Your MSD ignition is a cd (capacitor discharge) ignition system and it does not apply a pulse of 12 volts to the primary of the spark coil, but rather a pulse of current from a charged capacitor which are usually charged to a voltage from 150 v to 400 v. So you are applying initially a source of 150 v (at least) to the primary which was designed to withstand only 12 volts. The Accel coil withstands this abuse for a while, but probably the turn to turn insulation breaks down due to the high voltage pulses and then a turn to turn short occurs and that prevents the magnetic field in the coil to rapidly collapse and generate a high voltage pulse to the spark plug.
Ooops, didn't read your MSD specs. Pulses of 535 volts are being switched to the primary of your Accel coil which was designed for 12 v. And you expected it to work?
:eek:
[Modified by jfb, 10:18 PM 10/24/2002]
Ooops, didn't read your MSD specs. Pulses of 535 volts are being switched to the primary of your Accel coil which was designed for 12 v. And you expected it to work?
:eek:
[Modified by jfb, 10:18 PM 10/24/2002]
Instructor
Joined: Jan 2002
Posts: 221
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From: League city Texas
Re: [Ignition]: Ate up another Accel supercoil. (scorp508)
Scorp,
I am running a 6AL box, not quite as nice as yours, but anticipated a simular problem. I upgraded my distributor to a late model small cap HEI, a MSD cap and rotor kit and a MSD GM Blaster II coil. It took some small wiring changes and I had to fabricate a mounting bracket for the coil. The system has worked flawlessly since installation. If you need pics and wiring diagrams email me and I will send them to you. tupp@swbell.net.
I am running a 6AL box, not quite as nice as yours, but anticipated a simular problem. I upgraded my distributor to a late model small cap HEI, a MSD cap and rotor kit and a MSD GM Blaster II coil. It took some small wiring changes and I had to fabricate a mounting bracket for the coil. The system has worked flawlessly since installation. If you need pics and wiring diagrams email me and I will send them to you. tupp@swbell.net.
Thread Starter
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
Ooops, didn't read your MSD specs. Pulses of 535 volts are being switched to the primary of your Accel coil which was designed for 12 v. And you expected it to work?
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
Re: (scorp508)
Hey scorp,
I might be out in left field on this, but I just glanced down throught the post, I'm at work right now.
When we put the MSD 6al in the chevelle we had to take the HEI module out according to the directions and replace it with a small wiring harness provided in the kit. Are you still running the module(chip)? Perhaps that is why you are toasting the coils.
Just a quick thought. You may have already covered that though.
Jesse
I might be out in left field on this, but I just glanced down throught the post, I'm at work right now.
When we put the MSD 6al in the chevelle we had to take the HEI module out according to the directions and replace it with a small wiring harness provided in the kit. Are you still running the module(chip)? Perhaps that is why you are toasting the coils.
Just a quick thought. You may have already covered that though.
Jesse
Thread Starter
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
I'm using a GM HEI intall harness. You unplug everything from the distributor cap. Then you plug matching colored wires from the MSD box into the original 3-pin connector.... Pink, Black, Brown. Then you take the MSD's own 3-pin connector and plug that back into the dist. At that point you plug a red wire from the MSD into the original 12v battery wire from the dist, and a brown wire from the MSD into the original tach signal wire from the dist.
Burning Brakes
Joined: Apr 2002
Posts: 1,126
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From: Cleveland OH
Re: [Ignition]: Ate up another Accel supercoil. (jfb)
The Accel coil is designed to have a pulse of 12 v switched to its primary winding. The MSD circuitry charges a capacitor (have to guess, but probably to 150 v or more) and then connects this capacitor to discharge into the primary of the spark coil. This pulse exceeds the primary windings voltage and/or current rating and is the cause of failure. A spark coil designed for cd (capacitor discharge) service should be used with the MSD ignition.
Thanks,
Ron
Drifting
Joined: Aug 2002
Posts: 1,775
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From: Birmingham AL
Re: [Ignition]: Ate up another Accel supercoil. (scorp508)
I had a MSD 6AL box in my '87 Fiero GT. I used the harness and MSD's coil, so I never had problems with the coil. However, it ate ignition modules- like one every two weeks. Even good quality ones with correct installation and the grease on the bottom. The MSD coil might be too strong for an average ignition module- find a high performance one to go with a MSD coil if you keep that setup.
Safety Car
Joined: Apr 1999
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From: Ohio
Re: [Ignition]: Ate up another Accel supercoil. (scorp508)
Scorp, you're not the only one. I know a couple of guys I used to A-X with that fried those Accell Super coils with stock ignition systems. The dang things would melt a hole through the gray plastic. I've run an MSD 6A box with a Hypertech hot coil for five years without a problem. If you don't have an electrical wiring problem, you may want to try that brand.
Thread Starter
Team Owner
Joined: Mar 2000
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From: Boston, MA
Update..... I just got this email from MSD Tech..
Fair enough, sounds plausible. I just put an overnight w/saturday delivery order into Summit for that bushing and their HEI coil p/n 8225. We'll see if this helps. :)
Dear Sir;
You probably need to use a low resistance HEI bushing that goes under the coil. If you're using the stock bushing, too much heat can build up when using a CD ignition like the 6520 and can effect the entire secondary system. Our part number for the bushing is 8412.
Thank You,
MSD Tech
You probably need to use a low resistance HEI bushing that goes under the coil. If you're using the stock bushing, too much heat can build up when using a CD ignition like the 6520 and can effect the entire secondary system. Our part number for the bushing is 8412.
Thank You,
MSD Tech