It has a Mallory dual point distributer, it had the stock distributer, and did the same thing. Internal regulated coil, I had an external regulated coil and it did the same thing. They last about 6 months, then it develops a high RPM pop out the tail pipes, It acts like it wants to stall at idle, and sometimes it will backfire through the carb. I changed the coil again tonight, and it seems to be fine again. I've tried all different brands of coils, they all seem to last about 6 months. Thanks, Dean
I like this idea since bad grounds create so many peoblems but I would also call the tech hotline. I had a discussion about this type of thing a while back with one of distributor tech hotlines and we discussed burning up coils but I cannot recall how we left it. I don't recall exactly but one of the discussions ended with "don't do it that way or you'll burn up coils".
Maybe a bad ballast resistor. Check ALL your connections for corrosion, broken or grounded wiring, etc.....
Three possibilities that I can think of... 1) Grounding issues, as Leadsled mentioned. 2) Excessive heat in the area of the coil (or the coil is not able to shed heat because of something) 3) The coil is receiving current for excessive amounts of time without actually running (I've seen people who weren't aware of the "ACC" position on the ignition switch use "ON" to play their stereo for a couple of hours...the coil will get too hot to touch & fail after a number of these kinds of events).
I have found over the years that when a customer says " my car is eating coils" it is always the same thing. HEAT !! Excessive heat is caused by incorrect resistance in the primary ignition system. Typically a primary 12 volt circuit needs 3-4 ohms primary resistance. I like the Bosch "blue" coils because they have 4 ohms resistance and need NO ballast. If a ballast is used then you would need 1.5 ballast and a 1.5 ignition coil. Check the resistance of the coil etc........
Speaking of hot coils, don't leave the key on unless it's running. When I was trying to tune my WCFB i left the key on and my coil got too hot, cracked, and leaked coil oil all down the block.
What the others said. Not enough ballast resistor Heat Vibration The combination of heat and vibrtion Are you sure it's not just something loose in the power wire or connections into it (or ground) getting jiggled when you change it? How does it fail? Does it start arcing strangely? Does the primary open up or change resistance? What about the secondary? These may be things to track and help your diagnosis Good luck!
Ok, I installed a new coil last night, drove it about 4 miles, it seemed good. Left for work today, I drive about 50 miles one way. About 20 miles into the trip it starts cutting out, and dies. It's 4:30 in the morning, and raining. I try starting it as I'm rolling, no luck. Pull over, it just cranks. I pull the air cleaner, and check for fuel, it has fuel. I wiggle the wires on the coil, put the air cleaner back on, and it cranks, and pops. That's good, means I have spark. Crank some more, and it starts, and runs great the rest of the way to work, and all the way home. I checked to see if the coil was hot when it was stopped on the side of the road, and the coil was cool. I'm running an internal resisted coil. I have a 700r4 ****** with a single keyed hot wire for the lockup torque converter, and it's hooked to the coil. I'm going to change that, I need to find a stand alone wire to hook it to. I'm thinking, hopping' that the wire might be pinched where it goes under the firewall, and over the ******. I'm driving the wifes car tomorrow, and will be looking into this over the weekend. If I come up empty, I might put in the HEI I have, if it will clear the firewall. At least that would take all of the other parts out of the equation. I will also be looking at the engine to ch***is ground, body to ch***is ground, and battery to ch***is ground. This stuff really pisses me off. It's hard to fix this kind of thing. If it would just fail, I could find it. I don't have cell service from about the half way point of my commute, and I won't leave the truck on the side of the road. I think I need a blanket and a pillow, because I'll be sleeping in it until someone finds me. Maybe I should get that conceal and carry permit, and bring the gun along. Lots of scary people out there in the country. Thanks, Dean
You need to switch to HEI but if you do, make sure yoiu have the correct coil for the application. Call the tech hotline. These guys see this stuff every day. A fix can be real simple and you know the problem is real aggravating. I did an external coil HEI recently on a new build and when I called to ask how to wire it correctly, he asked about parts and said the coil I had was the wrong one. I had to get a different one. He said it would run for a while and then quit. Beats me, all I want to know about HEI is how to put the wires on.
The Jalopy Journal
