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  #21  
Old July 8th, 2017, 08:40 PM
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Quote:
Originally Posted by Nailhead View Post
The Pertronix collar should index to a notch on the distributor shaft. Mine did, and every distributor (ignitor, etc.) I've ever seen has had some similar feature to index the rotor.
Thank you, I will check that out. It did go down over the shaft fairly easy, so it must have been aligned correctly I hope. What is the purpose of the collar?
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  #22  
Old July 8th, 2017, 08:44 PM
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Originally Posted by rboltz View Post
As I've said before my "new" china coil lasted about 2 miles. Once they cool down, they will usually work again till hot. That being said, no way to test them unless you heat it up. The US NOS coils are now very hard to find.

Going back to points will not change the operation of the coil. I'm sure the electronic system you installed heats the coil just the same. I always thought those electronic systems had their own special coils but I now assume not.
I agree, with that being said, I will have to think about contacting the seller about a possible bad coil he sent me. Not sure I'll get anywhere with him, but 3 starts on a coil is just not acceptable in my opinion. Thanks.
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  #23  
Old July 8th, 2017, 10:02 PM
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Quote:
Originally Posted by militarypotts View Post
Thank you, I will check that out. It did go down over the shaft fairly easy, so it must have been aligned correctly I hope. What is the purpose of the collar?
If it is like the Chrysler electronic ignition of yesteryear, it may have tips (6 in our case) which stick out. As each tip passes the pickup coil, it induces a voltage in the pickup coil (not the Chinese coil ). That voltave is amplified and sent to the coil. The coil again amplifies the pulse which is sent to the center of the distributor cap. The rotor then directs it to the correct plug wire and the the high voltage jumps across the gap in the plug, setting off the compressed gasoline/air in the cylinder. That explolsion then pushes the piston down.

That collar was probably magnetic?
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  #24  
Old July 9th, 2017, 07:04 AM
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Quote:
Originally Posted by rboltz View Post
As I've said before my "new" china coil lasted about 2 miles. Once they cool down, they will usually work again till hot. That being said, no way to test them unless you heat it up. The US NOS coils are now very hard to find.

Going back to points will not change the operation of the coil. I'm sure the electronic system you installed heats the coil just the same. I always thought those electronic systems had their own special coils but I now assume not.
I don't have a Pertronix but read up on them a LOT when I was thinking of putting one in my Fairlane. There was tons of info on them at the Fairlane Club of America... but I've let my membership lapse due to lack of use.

From what I remember the Pertronix works with the stock coil but also has a preferred resistance range where performance is optimized. I think the guts of the Pertronix is the same across all applications but there's a wide range of coil resistance parameters across those applications. So the stock coil for your application may not be at the optimum range for the Pertronix for your application.

Some of the guys were using non stock coils with different resistance for better performance... but I don't remember what those numbers were.

Since you are pretty darned limited on coil options for the stock M715 distributor that information is fairly useless... as long as you want to keep the stock distributor.

But I was also just wondering if the chinese coils might last longer if a ballast resistor was used...?
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  #25  
Old July 9th, 2017, 10:34 AM
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Quote:
But I was also just wondering if the chinese coils might last longer if a ballast resistor was used...?
All the new coils have the ballast resistor built into the coil itself.
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  #26  
Old July 9th, 2017, 10:46 AM
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Quote:
Originally Posted by kwai View Post
All the new coils have the ballast resistor built into the coil itself.
Ahh... gotcha. Forgot that was mentioned earlier. So.. just junk with no workaround then.

I loves me some HEI.
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  #27  
Old July 9th, 2017, 05:15 PM
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I contacted the seller and he is sending a new coil to me, (I have to pay the $8 postage and handling fee). I don't have a problem with that though. I was just happy he took my word that I only got 3 starts on the first coil he sent me. He told me to keep the other coil he originally sent. I was willing to send it back to him, but he didn't want it back. I still need to check for 24 volts at the distributor. I'll drop in the new coil when I get it and hope for the best.
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  #28  
Old July 9th, 2017, 10:55 PM
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I am pretty certain that the coil in my truck is an M-37 coil. I paid $60.00, used, tested.

So, the question is, will any other 6-cylinder coil work? How about from a gasser deuce? 5-ton gasser? All of them were 24-Volt. Any former motor pool guys out there?

Anyone, anyone, anyone, Bueller, Bueller, Bueller?
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  #29  
Old July 9th, 2017, 11:53 PM
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With all the coils out there from other motors, why is the coil for the M715 so specific to the vehicle? I'm a home garage mechanic and know my knowledge is somewhat limited, but I just don't understand the principle behind this M715 coil problem so many of us have. Does the ignitor being fairly close to the exhaust manifold have anything to do with it? Of course, all of this talk and it may not even be the coil.
One thing I forgot to mention early on in this thread was that the coil the guy sent the first time had a date written on it in magic marker. That date said 2008. He assured me it was a display coil and had never been used before. Can a coil go bad sitting on a shelf over the years? I would think that summer heat and humidity might have an adverse effect on it over a period of time. Also, is their any way to tell if your cap and rotor are good or bad? I've inspected mine and truthfully, they look to be in outstanding condition. I'm trying to cover all my bases here, as I'm pretty frustrated at this problem I'm having.
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  #30  
Old July 10th, 2017, 02:57 AM
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Sitting on the shelf should not cause it to go bad. Remember coils on civilian vehicles were out in the weather 24-7.

Since the Chinese coils seem to have a problem, I think it comes down to just plain poor manufacturing. How many brand name batteries have destroyed electronic equipment, remotes, volt meters, flashlights that you own? And before their expiration date. I have had Duracell, Energizer, Ray-O-Vac, you name it, just leak all over. Where were they made? You guessed it, China.

I suspect these coils are just made with inferior insulation on the windings...

Is there some one of us who can answer my question above about other 6-cylinder engines?
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