Ignition shield cover shorting out coil
My '69 L36 lost it's original coil before my time. Since rebuilding the engine, I bought a GM Restoration Parts coil #1115287. I have the correct coil bracket and capacitor. When the coil sits in the bracket, it remains about 1/8" or so above the manifold, but the bottom rear edge does contact the manifold bolt...so it cannot go down further into the bracket. I have 'Lectric Ltd reproduction plug wires and coil wire. When I install the original cover (with inner insulator intact) over the ignition shielding, the ignition is dead. Has anyone else had a similar problem with this reproduction coil? Is it possible that it is physically taller than an original?
-
-
Re: Ignition shield cover shorting out coil
John
Thanks for the tip. I'm going to try a new coil to cap wire and put the cover on, just to see if that is the problem.
DennisComment
-
Re: Ignition shield cover shorting out coil
Your statement that the ignition is dead means what; no spark?
Check the wire before you replace it. Then you will know if that was the problem before replacing.Comment
-
Re: Ignition shield cover shorting out coil
Car starts and runs fine with no ignition shield cover installed. Put the cover on, the engine will not fire. Put a piece of rubber under the cover and it starts, but tends to miss as the RPMs go up. Take the cover off and it runs like a champ. This LL wire set is almost new and has never caused me a problem. The problem began when I changed the coil to this GM repop.Comment
-
Re: Ignition shield cover shorting out coil
Dennis,
Look to see if you have have the coil clocked differently to before. Maybe one of the wires is closer to the shielding than before or even touching.Chip.Comment
-
Re: Ignition shield cover shorting out coil
Paul
Thanks for the suggestion and realize a year has gone by. Problem no longer intermittent and getting worse. Measured 11.33 volts on coil positive at idle. Decided to use a jumper wire from 14.66 system volts on the horn relay and go for a drive. Problem gone. Something must be wrong with the $95 repro coil made in China. Monday I plan on swapping the coil with a known good and run on normal ignition voltage thru the resistor wire. If the problem is no longer there, then I know it is the coil.
DennisComment
-
Re: Ignition shield cover shorting out coil
Two comments for you. I have a '69 with a BB L68 tri-power with TI. The AIM gives a specific clocking for the coil primary terminals which in my case puts them very close to the shielding screw tab and other wire shielding that route over the coil area on the left side. I have a correctly stamped coil and with the factory clocking the number was visible for judging but I couldn't bring myself to run the car that way. I was afraid of shorting the TI electronics. Turning the coil in the bracket a few degrees added some clearance. You can also push the whole box to tweek the brackets left and right as needed.
I also purchased a foreign made coil from Paragon for the correct markings. With the TI it barely ran. I have the original electronics in the TI module. I tried replacing it with my stand-by solid state box but no change. Put the old coil back on and it was fine. I sent the coil back and ordered their Made in America coil and it worked fine.Last edited by Michael B.; February 28, 2011, 11:17 AM.Comment
-
Re: Ignition shield cover shorting out coil
I tend to endorse the LL wires. I have had mine on since early 90's w/o any problems. Still pulls redline using Pertronics II conversion and FT coil. Mine is a 63 and I've had the shielding on and off many times, and the wires are packed in tight, but with extra separaters. I also coated the shield insulator rivets with silcone to be extra cautious.
Stu FoxComment
-
Re: Ignition shield cover shorting out coil
Michael
I probably have 3/8" clearance from coil positive to the shielding screw tab. Really don't think that is or was the problem.
Stuart
Just replaced the repro coil with a borrowed new Pertronix Flamethrower 1.5 ohm coil and the car goes like a bat outa hell, all the way to redline. Even idles better and sounds better. No more popping in the exhaust or jerking at steady low rpm in 1st and 2nd gear. The coil fits the bracket even better than the repro and seems to be a little shorter, which will allow me to lift it slightly and eliminate contact with an intake manifold bolt. After the engine cools, I'm going to put all the shielding back on and check again. Are there any potential problems using this coil with my otherwise stock ignition system?Comment
-
Re: Ignition shield cover shorting out coil
Dennis;
Not knowing what the rest of the specs are for your ignition system, I can only state that the Flamethrower 1.5 ohm coil should work as well as any aftermarket performance coil designed for use with a stock ignition. I should have stated that mine is the Flamethrower II 0.6 ohm coil which I use with their Pertronix II conversion. As such, I use a straight 12 volt input to the coil w/o a ballast resistor. To do that, and make it look like stock, I jumper around/across the existingballast resistor with a black HD wire so it does the trick and is not so obvious.
Hope your car will run well with the shielding in place.
Stu FoxComment
-
Re: Ignition shield cover shorting out coil
Thanks Stuart. That's what I thought, the Pertronix ignition module requires jumpering the resistor wire in the engine harness and probably uses a coil with less impedance. All's well that ends well, at least until the next revelation.
Noticed on the box that Pertronix is made in China too.............Last edited by Dennis S.; February 28, 2011, 05:20 PM.Comment
-
Re: Ignition shield cover shorting out coil
Stuart
The car ran good for a few miles, then started cutting out again at WOT. Found the HD Blue Streak points set with less than 1200 miles was burned. Put a NAPA set in and runs fine again. Time will tell.Comment
-
Re: Ignition shield cover shorting out coil
Dennis;
Are you using a ballast resistor? Sounds like you are running full time 12 volts to your system which will fry any points you use.
Stu FoxComment
-
Re: Ignition shield cover shorting out coil
Stuart
Resistor wire, which hopefully is still good and not getting weird as it heats up. I've put in new LL harnesses in front of the firewall, but not behind. I'm reading just a little over 10 volts with a digital multimeter at coil positive when idling. Plan on checking it both cold and hot after a long drive. Could have burned the points when I jumpered system voltage to the GM repro coil for a quick test run, as previously mentioned. I'm going to run it with this Flamethrower coil for a while, no shielding, and see how it does. When I get tired of buying points (soon) I may just go the Pertronix II route.Comment
Comment